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16 páginas.- 6 figuras.- 1 tabla.- referencias.- Supplementary information The online version contains supplementary material available at https://doi. org/10.1007/s11104-023-06029-z, Purpose Incorporating biosolids into the soil improves plant yield compared with surface application, but it can result in the increased uptake of trace elements. However, there is a lack of knowledge about how different types of biosolids applications affect soil quality. We aimed to determine the effect of the type and rate of biosolids application on soil quality and the mobility of contaminants. Methods Soil quality was determined by soil fertility (inorganic N, exchangeable P, Mg, Ca, K), exchangeable trace and non-essential elements (Al, Mn, Zn, Cu and Cd) and biological activity (dehydrogenase activity). We measured the properties of soil pore water, bulk soil and rhizosphere in a pot and a rhizobox experiment, with increasing concentration of biosolids (equiv. 16 t ha− 1, 48 t ha− 1 and 145 t ha− 1 dry weight), applied on the surface, incorporated to 25 cm, or incorporated into a patch. Results and discussion The incorporation of biosolids into the soil increased the exchangeable Zn, Cu, Cr, Ni and Cd, compared with surface application. The surface application of biosolids increased the inorganic N in the soil compared with biosolids incorporation (680 mg kg− 1 vs. 380 mg kg− 1), and decreased soil pH by 1.1 units. This aligned with solubilisation of Al (43 mg kg− 1 vs. 6 mg kg− 1) and Mn (43 mg kg− 1 vs. 33 mg kg− 1) and explains the decreased microbial activity in the soil compared with the unamended soil. Incorporating biosolids in the soil increased the biological activity, likely due to biosolids-borne microbes. The root systems significantly increased microbial activity, pH, and the concentration of NH4+, NO3−, and exchangeable P, S, Mg, Na, Zn, Cu and Ni, and significantly decreased exchangeable concentration of Mn and Fe., his study was funded by the Centre for Integrated Biowaste Research which was supported by ESR Strategic Science Investment Funding from the Ministry of Business, Innovation and Employment, New Zealand (C03X1701). We acknowledge the staff in the Lincoln University greenhouse facilities and in the laboratories of the Soil Department, where all the experimental work took place. We thank Christchurch City Council for providing the biosolids. During her postdoc position in Lincoln University (New Zealand), MJGG held a fellowship granted by Fundación Ramón Areces (Spain). EM thanks the financial support for her work at Lincoln University from Program Salvador de Madariaga of the Spanish MECD.

Trigonometric polynomials are usually defined on the lattice of integers.We consider the larger class of weight and root lattices with crystallographic symmetry.This article gives a new approach to minimize trigonometric polynomials, which are invariant under the associated reflection group.The invariance assumption allows us to rewrite the objective function in terms of generalized Chebyshev polynomials. The new objective function is defined on a compact basic semi-algebraic set, so that we can benefit from the rich theory of polynomial optimization.We present an algorithm to compute the minimum: Based on the Hol-Scherer Positivstellensatz, we impose matrix-sums of squares conditions on the objective function in the Chebyshev basis.The degree of the sums of squares is weighted, defined by the root system. Increasing the degree yields a converging Lasserre-type hierarchy of lower bounds.This builds a bridge between trigonometric and polynomial optimization, allowing us to compare with existing techniques.The chromatic number of a set avoiding graph in the Euclidean space is defined through an optimal coloring.It can be computed via a spectral bound by minimizing a trigonometric polynomial. If the to be avoided set has crystallographic symmetry, our method has a natural application.Specifically, we compute spectral bounds for the first time for boundaries of symmetric polytopes.For several cases, the problem has such a simplified form that we can give analytical proofs for sharp spectral bounds.In other cases, we certify the sharpness numerically.

The use of vegetation roots as a nature-based solution against landslides and erosion requires the definition of sample preparation protocols and adoption of equipment that allows testing representative elementary volumes of the whole soil-root system. For this purpose, large cell triaxial compression tests were carried out on fallow and vegetated samples at different degrees of saturation. Samples were prepared by static compaction of a silty sand and seeded with Cynodon dactylon. The hydraulic state during plants growth was controlled and reproduced on bare soil samples. After isotropic compressions, the shearing phase was carried out at very low confining stresses (i.e., below 50 kPa). Tests were deemed to be comparable by assessing the normalised volume of roots with respect to soil, after shearing. For a given confining stress, soil samples with higher matric suction exhibited higher shear strength, furtherly increased by roots. The stress-strain behaviour observed in the vegetated soil systematically changed, when comparing tests at low and high matric suction values, due to the different mechanisms of vegetation reinforcement depending on the hydraulic state at the soil-root interface. The results were successfully interpreted within a failure criterion and skeleton stress framework for partially saturated soils, considering soil suction, degree of saturation, soil microstructure and the normalised volume of roots.

Ce mémoire étudie deux familles de fonctions orthogonales, soit les fonctions d'orbite de Weyl et les fonctions d'orbite de Hartley. Chacune de ces familles est associée à une algèbre de Lie simple et cette recherche se limite aux algèbres A₂, C₂ et G₂ de rang 2. Les fonctions d'orbite de Weyl ont été largement étudiées depuis des années en raison de leurs propriétés exceptionnelles. Nouvellement, elles ont été utilisées pour générer des polynômes de Chebyshev généralisés et calculer les fonctions génératrices de ces polynômes pour les algèbres de Lie simples de rang 2. Les fonctions d'orbite de Hartley, quant à elles, ont été récemment introduites par Hrivnák et Juránek et l'étude de ces dernières ne fait que débuter. L'objectif de ce mémoire est de définir des polynômes de Chebyshev généralisés associés aux fonctions de Hartley et de calculer les fonctions génératrices de ceux-ci pour les algèbres A₂, C₂ et G₂. Le premier chapitre introduit les systèmes de racines et le groupe de Weyl, original et affine, ainsi que leurs domaines fondamentaux, afin que le lecteur ait les notations et définitions pour comprendre les chapitres suivants. Le deuxième chapitre présente et étudie les fonctions de Weyl. Il définit également leurs polynômes de Chebyshev généralisés et se termine en présentant les différentes fonctions génératrices de ces polynômes pour les algèbres de Lie simples de rang 2. Finalement, le troisième chapitre contient les résultats originaux; il expose les fonctions de Hartley et certaines de leurs propriétés. Il définit les polynômes de Chebyshev généralisés de celles-ci et énonce également leurs relations d'orthogonalité discrète. Il conclut en calculant les fonctions génératrices de ces polynômes pour les algèbres A₂, C₂ et G₂., This master's thesis studies two families of orthogonal functions, the Weyl orbit functions and the Hartley orbit functions. Each of these families is associated to a simple Lie algebra and the present work is limited to the algebras A₂, C₂ and G₂ of rank 2. Weyl orbit functions have been widely studied for years because of their exceptional properties. Recently, these properties have been used to generate generalized Chebyshev polynomials and to compute the generating functions of these polynomials for the simple Lie algebras of rank 2. Hartley orbit functions, on the other hand, were recently introduced by Hrivnák and Juránek and the study of the latter has only begun. The objective of this thesis is to define the generalized Chebyshev polynomials of Hartley orbit functions and to compute their generating functions for the algebras A₂, C₂ and G₂. The first chapter introduces root systems and the Weyl group, original and affine, and their fundamental domains, so that the reader has the notations and definitions at hand to read the following chapters. The second chapter introduces and studies Weyl orbit functions. It also defines their generalized Chebyshev polynomials and ends by presenting the different generating functions of these polynomials for simple Lie algebras of rank 2. Finally, the third chapter contains the original contribution; it presents the Hartley functions and some of their properties. It defines the generalized Chebyshev polynomials of these and also states their discrete orthogonality relations. It concludes by computing the generating functions of these polynomials for the algebras A₂, C₂ and G₂.

The role and features of the European spruce root systems structure in the conditions of recreational load in the tourist routes area of the Carpathian National Nature Park (NNP) are described. The aim of the study is to establish the ratio of the volume and surface area that interacts with the soil for conductive and physiologically active roots as a prerequisite for anti-erosion resistance of spruce phytocenoses under recreational load conditions. To determine the silvicultural and biometric indicators of tree species at the forest stand 13 circular and semicircular temporary trial areas were laid down according to the method which had become well established and commonly usedin forest measurement and forest management. The studied plantations are mostly pure in composition, less often mixed with the predominance of European spruce and 1-2 units’ participation in the forest composition by beech (Fagus sylvatica L). or single specimens of the genus Salix L. The age structure is dominated by medieval and pre-mature stands. The root systems are the main anti-erosion element of forest phytocenosis on sloping lands, where the leading (skeletal) roots provide consolidation of trees in a vertical position, and physiologically active - provides soil consolidation, participates in the formation of waterproof aggregates, improving soil permeability and activation of soil-forming processes. An important indicator of the roots involvement in the landscapes erosion resistance increasing is their volume and surface area, which interacts with the soil solution. The main role in the absorption of nutrients by the underground part of the tree is played by physiologically active roots. There is a natural competition between the root systems in both pure and mixed stands. A denser interweaving of root systems is observed on nutrient-rich soils. However, the high density of root systems is due to the water limit on limited access to nutrients. The plasticity of the physiological root, its biomass and the density of distribution indicate the level of ability to compete for habitat. 136 samples of root-containing soil layer at a depth of 0-10 cm, 10-20, 20-30 and 30-40 cm were taken from the sample areas of stands growing in clean and with a small participation of medieval beech forest and ripening stands, from which the roots of European spruce were isolated from division into conductive and physiologically active roots. Also volumes and surface areas of these roots have been calculated. Statistical correlations between altitude and the volume of the fraction of physiologically active and conductive roots were established, the correlation coefficients of which are 0.78 and 0.47, respectively. The distribution of the root systems of European spruce depending on the depth of the parent rock showed that in the upper mineral layers of the soil by volume the fraction of the leading root predominates. In some cases, its volume increases with depth, which affects the density of the conductive root. The surface area of the roots is dominated by physiologically active roots at a depth of 0-20 cm, while at a depth of 20-30 there is a predominance of the leading root. In plantations with stronger soil profiles (over 30 cm) in the upper layers (0-20 cm) and at a depth of 30-40 cm the fraction of the leading root predominates, but at a depth of 20-30 cm this tendency changes in favor of physiologically active roots. The main part of the roots is located in the upper mineral layer of the soil at a depth of up to 10 cm on the objects of nature reserves, which are more sensitive to recreational loads in thе mountain conditions. In this soil horizon the share of conducting and physiological roots of the total volume of each fraction is 67.5 and 75.3%, and in places with rock outcrops - 72.7 and 87.5%, respectively.

We develop an algorithm for computing the cohomology of complements of toric arrangements. In the case a finite group $$\Gamma $$ Γ is acting on the arrangement, the algorithm determines the cohomology groups as representations of $$\Gamma $$ Γ . As an important application, we determine the cohomology groups of the complements of the toric arrangements associated with root systems of exceptional type as representations of the corresponding Weyl groups.

The Weyl group of a crystallographic root system has a multiplicative action on the ring of multivariate trigonometric polynomials. We study the problem of minimizing an invariant trigonometric polynomial. This problem can be written as a polynomial optimization problem on a compact basic semi-algebraic set. Lasserre's moment-SOS hierarchy is formulated in the basis of generalized Chebyshev polynomials, leading to a different notion of the polynomial degree and smaller matrices in the arising semi-definite program. Bilevel optimization techniques are applied to solve max-min problems. Optimal values of trigonometric polynomials appear in spectral bounds for chromatic numbers and independence numbers of geometric distance graphs. We study the quality of these bounds for polytope norms and prove sharpness in several cases.

This thesis studies the problem of optimizing a trigonometric polynomial with crystallographic symmetry. Optimization of trigonometric polynomials has been subject to many recent works, but a theory for exploiting symmetries has hardly been developed or generalized. We consider the action of a crystallographic group, also known as a Weyl group, on the exponents. This action admits a definition of generalized Chebyshev polynomials. If a trigonometric polynomial is invariant under the action, then it can be written as a sum of generalized Chebyshev polynomial in fundamental invariants.By rewriting an invariant trigonometric polynomial as a classical polynomial, the region of optimization is transformed into the orbit space of the multiplicative Weyl group action. This orbit space is the image of fundamental invariants and we show that, for the Weyl groups of types A, B, C, D and G, it is a compact basic semi-algebraic set. Furthermore, we give the describing polynomial inequalities through a positive semi-definite Hermite matrix polynomial.Concerning the optimization problem, our rewriting approach transforms the trigonometric optimization problem into a classical polynomial optimization problem on a basic semi-algebraic set. To solve such problems, one can apply Lasserre's hierarchy of moment and sum of squares relaxations. We adapt and implement this hierarchy in the basis of generalized Chebyshev polynomials with a new notion of degree. The optimal value of the original trigonometric optimization problem is then approximated through solutions of semi-definite programs, which are solved numerically.In classical polynomial optimization and other applications, symmetry adaptation has been studied and implemented, but crystallographic symmetries have not been exploited in trigonometric optimization before. With our approach, we provide an alternative to known strategies for trigonometric optimization. Where other techniques utilize sums of Hermitian squares or generalizations of Lasserre's hierarchy to the complex setting, we exploit symmetry first and then apply techniques from classical polynomial optimization. This reduces the size of arising semi-definite relaxations and can also improve the quality of the approximation.As an application, we study the problem of computing lower bounds for the chromatic number of geometric distance graphs. Given a norm and a set of vertices, this problem asks to find the minimal number of colors needed to paint the vertices, so that no two of those of distance 1 between them have the same color. The spectral bound was generalized from finite to infinite graphs to deal with such problems. This bound involves the optimization of a trigonometric polynomial. We focus on norms which are given by polytopes with crystallographic symmetry. Then the problem can be tackled with the techniques developed in this thesis. We give several bounds through analytical and numerical computations., Cette thèse étudie le problème de l'optimisation d'un polynôme trigonométrique avec symétrie cristallographique. L'optimisation des polynômes trigonométriques était l'objet de nombreux travaux récents, mais une théorie permettant d'exploiter les symétries n'a pas été développée ou généralisée. Nous considérons l'action d'un groupe cristallographique, également connu sous le nom de groupe de Weyl, sur les exposants. Cette action admet une définition des polynômes de Chebychev généralisés. Si un polynôme trigonométrique est invariant sous l'action, il peut être écrit comme une somme de polynômes de Chebyshev généralisés dans les invariants fondamentaux.En réécrivant un polynôme trigonométrique invariant comme un polynôme classique, la région d'optimisation est transformée en l'espace d'orbite de l'action du groupe de Weyl multiplicatif. Cet espace d'orbite est l'image des invariants fondamentaux et nous montrons que, pour les groupes de Weyl de types A, B, C, D et G, il s'agit d'un ensemble compact basique semi-algébrique. En plus, nous donnons les inégalités polynomiales descriptives à par un matrix polynomial positif de Hermite.En ce qui concerne l'optimisation, notre approche de réécriture transforme le problème d'optimisation trigonométrique dans un problème d'optimisation polynomiale sur un ensemble basique semi-algébrique. Pour résoudre de tels problèmes, on peut appliquer la hiérarchie des relaxations de moment et de somme de carrés de Lasserre. Nous adaptons et implémentons cette hiérarchie sur la base de polynômes de Chebyshev généralisés avec une nouvelle notion de degré. La valeur optimale du problème d'optimisation trigonométrique original est alors approximée par des solutions de programmes semi-définis, qui sont résolus numériquement.Dans l'optimisation polynomiale classique et d'autres applications, l'adaptation des symétries a été étudiée et implémenté, mais les symétries cristallographiques n'ont pas été exploitées en optimisation trigonométrique auparavant. Avec notre approche, nous fournissons une alternative aux stratégies connues pour l'optimisation trigonométrique. Alors que d'autres techniques utilisent des sommes de carrés Hermitiens ou en généralisant l'hiérarchie de Lasserre au cadre complexe, nous exploitons d'abord la symétrie et appliquons ensuite des techniques d'optimisation polynomiale classique. Cela réduit la taille des relaxations semi-définies qui en découlent et peut également améliorer la qualité de l'approximation.En guise d'application, nous étudions le problème de calcul des bornes inférieurs pour le nombre chromatique des graphes géométriques. Étant donné une norme et un ensemble de sommets, ce problème demande de trouver le nombre minimal de couleurs nécessaires pour peindre les sommets, de sorte que deux de ceux de distance 1 entre eux n'aient pas la même couleur. La borne spectrale a été généralisée des graphes finis aux graphes infinis pour traiter de tels problèmes. Cette limite implique l'optimisation d'un polynôme trigonométrique. Nous nous concentrons sur les normes qui sont données par des polytopes avec une symétrie cristallographique. Le problème peut alors être abordé avec les techniques développées dans cette thèse. Nous donnons plusieurs bornes à travers des calculs analytiques et numériques.

Understanding the relationship between root systems, soil macropore networks, and soil hydraulic properties is important to better assess ecosystem health. In this study, treatments were performed in forested wetland soils with different vegetation densities, i.e., large (LWa) and small communities (LWb) of reed (Phragmites australis (Cav.) Trin. ex Steud.). At each plot, three undisturbed PVC cylinders (10 cm in diameter and 50 cm in height) were obtained, and X-ray microtomography (μCT) scanning was used to determine the root and macropore architectures. Results showed that the values of total root length and total root volume at LWa were significantly larger than those at LWb (p < 0.05). Imaged macroporosity, macropore volume, macropore length density, macropore node density, macropore branch density, mean macropore surface area, mean macropore diameter, and mean macropore volume at LWa were significantly larger than those at LWb (p < 0.05), whereas mean macropore length, mean macropore branch length, and mean macropore tortuosity at LWb were larger than those at LWa. Total root length and total root volume were positively correlated with soil saturated hydraulic conductivity. Imaged macroporosity, macropore volume, macropore length density, macropore node density, macropore branch density, mean macropore surface area, mean macropore diameter, and mean macropore volume were positively correlated with soil saturated hydraulic conductivity, whereas mean macropore length, mean macropore branch length, and mean macropore tortuosity were negatively correlated with soil saturated hydraulic conductivity. In conclusion, root systems and soil macropore networks constitute a complex synthesis inside soil environments, and together affect soil hydrological responses.

The hydrological connectivity below the soil surface can influence the forest structure and function, especially soil and plant productivity. However, few studies have determined the changes in the hydrological connectivity below the soil surface with increasing soil depth and have quantified the effects of root systems on the hydrological connectivity in forest ecosystems. In this study, we evaluated the index of the hydrological connectivity (IHC) below the soil surface using a field dye tracing method and compared the difference in the index of hydrological connectivity in two subtropical forest stands (i.e., pine trees [SS] and bamboo [ZL]). We analyzed the interactions between the parameters of root system architecture and the index of hydrological connectivity. Back propagation (BP) neural networks were used to quantify which parameter can contribute the most relative importance to the changes of the IHC. The results revealed that the maximum value of the index of hydrological connectivity occurs at the soil surface, and it exhibits a non-linear decreasing trend with increasing soil depth. The parameters of root system architecture (root length, root projected area, root surface area, root volume, and root biomass) were rich in the top soil layers (0–20 cm) in the two sites. Those parameters were positively correlated with the IHC and the root length had the largest positive influence on the hydrological connectivity. Furthermore, we found that root system architecture with different root diameters had different degrees of influence on the index of hydrological connectivity. The very fine root systems (0 < D < 1 mm) had the greatest effect on the hydrological connectivity (p < 0.01). The results of this study provide more information for the assessment of the hydrological connectivity below the soil surface and a better understanding of the effects of root systems in soil hydrology within the rhizosphere.

Upland rice is cultivated mostly in Latin America and Africa by small farmers and in areas with risk of dry spells. This study evaluated morphophysiological mechanisms of upland rice associated to drought adaptation. A set of 25 upland rice genotypes were grown in a plant phenotyping platform during 2015 and 2017 under regular irrigation and water restriction. We evaluated morphophysiological traits in shoots (vegetative structures growth, gas exchange, water use efficiency, carboxylation efficiency, water status) and roots (length, surface area, volume and diameter), as well as agronomic traits (grain yield and its components). There was a reduction in grain yield by up to 54 % and 58 % in 2015 and 2017, respectively, under water deficit. Five upland rice genotypes with the best yield performances in both water treatments applied were recommended to the upland rice-breeding program: Bico Ganga, BRS Esmeralda, BRSMG Curinga, Guarani, and Rabo de Burro. In this study, morphophysiological traits associated to drought tolerance concerned the plant high capacity to save water in the leaves, low leaf water potential, high ability to reduce vegetative structures, high water use efficiency, high photosynthetic capacity, and improved capacity to absorb water from drying soil, either by osmotic adjustment or additional investment into the root system. Therefore, we concluded that different secondary traits contributed to drought tolerance and should be evaluated along with grain yield to improve efficiency of breeding selection. Made available in DSpace on 2020-11-10T09:17:25Z (GMT). No. of bitstreams: 1 SciAgric-2021.pdf: 1083892 bytes, checksum: 229f86b1cca0d54b92dab1a2f7b69135 (MD5) Previous issue date: 2021

International audience; Summary Soil aggregates are critical to soil functionality, but there remain many uncertainties with respect to the role of biotic factors in forming aggregates. Understanding the interacting effects of soil, land use type, vegetation and microbial communities is a major challenge that needs assessment in both field and controlled laboratory conditions, as well as in bulk and rhizosphere soils. To address these effects and their feedbacks, we first examined the influence of soil, root and litter characteristics along a land use gradient (ancient woodland, secondary woodland, grassland, pasture and arable land) on microbial community structure (in both bulk and rhizosphere soil), as well as on aggregate stability. Then, we performed an inoculation experiment where we extracted soil columns from the arable and secondary woodland and used a third unstructured loamy soil as a control. We sterilized these three soils to remove microbial communities, and then either inoculated the tops of sterilized soil columns with soil from the secondary woodland or the arable field sites. Control columns of all soil types were not inoculated. In a fully-crossed design, we planted two species possessing distinct root system morphological traits: Brachypodium sylvaticum (fibrous system with many thin and fine roots) and Urtica dioica (taproot system with few fine roots). After four months, microbial communities (in bulk and rhizospheric soil) and aggregate stability were measured, along with root traits. In both the field and laboratory experiments, bacterial (16S) and fungal (ITS) biodiversity was determined using high throughput sequencing. In the field study we found that: i) there were strong relationships between aggregate stability and microbial community composition that were driven by land use, ii) the relationship between aggregate stability along the land use gradient and the trophic nature of bacterial communities was not significant, but that certain soil, root and litter parameters shaped bacterial phyla, with oligotrophic bacteria conditioned by the rhizosphere niche, and copiotrophic phyla more dependent on bulk soil conditions, iii) land use gradient (from woodland to arable), reduced the relative abundance of saprotrophic and ectomycorrhizal fungi with an increase in the relative abundance of Ascomycota and a reduction in the relative abundance of Basidiomycota. In the laboratory experiment we found that: i) the inoculation of sterilized soils with soils from the field significantly increased aggregate stability in control soil that was initially poorly structured, ii) the effects of inoculation on aggregate stability were similar when either secondary woodland or arable soils were used as inoculums and iii) these effects were affected significantly by root length density. Our results show that microbial communities influence soil structure and that bacterial communities are intimately associated to rhizospheric conditions and root traits (of which root length density was the most pertinent).

The Rhizotrons method is an important means of detecting dynamic growth and development phenotypes of plant roots. However, the segmentation of root images is a critical obstacle restricting further development of this method. At present, researchers mostly use direct manual drawings or software-assisted manual drawings to segment root systems for analysis. Root systems can be segmented from root images obtained by the Rhizotrons method, and then, root system lengths and diameters can be obtained with software. This type of image segmentation method is extremely inefficient and very prone to human error. Here, we investigate the effectiveness of an automated image segmentation method based on the DeepLabv3+ convolutional neural network (CNN) architecture to streamline such measurements. We have improved the upsampling portion of the DeepLabv3+ network and validated it using in situ images of cotton roots obtained with a micro root window root system monitoring system. Segmentation performance of the proposed method utilizing WinRHIZO Tron MF analysis was assessed using these images. After 80 epochs of training, the final verification set F1-score, recall, and precision were 0.9773, 0.9847, and 0.9702, respectively. The Spearman rank correlation between the manually obtained Rhizotrons manual segmentation root length and automated root length was 0.9667 (p < 10–8), with r2 = 0.9449. Based on the comparison of our segmentation results with those of traditional manual and U-net segmentation methods, this novel method can more accurately segment root systems in complex soil environments. Thus, using the improved DeepLabv3+ to segment root systems based on micro-root images is an effective method for accurately and quickly segmenting root systems in a homogeneous soil environment and has clear advantages over traditional manual segmentation.

We compute the total cohomology of the complement of the toric arrangement associated to the root system $A_n$ as a representation of the corresponding Weyl group via fixed point theory of a "twisted" action of the group. We also provide several proofs of an explicit formula for the Poincar\'e polynomial of the complement of the toric arrangement associated with $A_n$., Comment: 14 pages. The contents have been extracted from a previous version of arXiv:1601.01857

The identification of genotypes more tolerant to water deficit and more efficient in the use of nutrients little available in the soil is an important low-cost strategy to promote sustainable agriculture in marginalized regions. In this sense, a study was carried out in the SITIS Phenotyping Platform of the Embrapa Arroz e Feijão, with the objective of evaluating the drought tolerance of upland rice genotypes tolerant to phosphorus (P) deficiency. The experimental design was performed in a randomized complete block with split-split plots and two replications. In the plots were established two water regimes (with and without water deficit), in the subplots two soil phosphorus contents (25 and 200 mg dm-3) and in sub-subplots 48 upland rice genotypes. The water deficit had more impact on grain yield than the phosphorus supply. The genotypes AB 062037, AB 062041, AB 062138, Arroz Mato Grosso, BRA 02601, BRA 052045, CNA 4098, CNA 6187, Guapa, Guaporé and Rio Paranaíba were classified in the most productive group under both water regimes. The most productive genotypes under water deficit showed higher root density in the deeper soil layers. The most productive genotypes in the two water regimes were also those that showed the highest transpiration. RESUMO A identificação de genótipos mais tolerantes à deficiência hídrica e mais eficientes no uso de nutrientes pouco disponíveis no solo é uma importante estratégia de baixo custo para promover a agricultura sustentável em regiões marginalizadas. Neste sentido, foi conduzido um estudo na Plataforma SITIS de Fenotipagem da Embrapa Arroz e Feijão, com o objetivo de avaliar a tolerância à deficiência hídrica de genótipos de arroz de terras altas tolerantes à deficiência de fósforo. O delineamento experimental foi blocos ao acaso, com parcelas subsubdivididas, com duas repetições. Nas parcelas foram estabelecidos dois regimes hídricos (com e sem deficiência hídrica), nas subparcelas dois teores de fósforo no solo (25 e 200 mg dm-3) e nas subsubparcelas 48 genótipos de arroz de terras altas. A deficiência hídrica teve mais impacto na produtividade de grãos do que o suprimento de fósforo. Os genótipos AB 062037, AB 062041, AB 062138, Arroz Mato Grosso, BRA 02601, BRA 052045, CNA 4098, CNA 6187, Guapa, Guaporé e Rio Paranaíba foram classificados no grupo mais produtivo sob ambos regimes hídricos. Os genótipos mais produtivos sob deficiência hídrica apresentaram maior densidade do sistema radicular nas camadas mais profundas do solo. Os genótipos mais produtivos nos dois regimes hídricos foram também aqueles que apresentaram maior transpiração.

Cluster structures have been established on numerous algebraic varieties. These lectures focus on the Grassmannian variety and explain the cluster structures on it. The tools include dimer models on surfaces, associated algebras, and the study of associated module categories.

We consider a certain linear combination of zeta-functions of root systems for a root system. Showing two different expressions of this linear combination, we find that a certain signed sum of zeta-functions of root systems is equal to a sum involving Bernoulli functions of root systems. This identity gives a non-trivial functional relation among zeta-functions of root systems, if the signed sum does not identically vanish. This is a generalization of the authors' previous result (Proc. London Math. Soc. 100 (2010), 303–347). We present several explicit examples of such functional relations. We give a criterion of the non-vanishing of the signed sum, in terms of Poincaré polynomials of associated Weyl groups. Moreover we prove a certain converse theorem.

International audience; Sparse interpolation refers to the exact recovery of a function as a short linear combination of basis functions from a limited number of evaluations. For multivariate functions, the case of the monomial basis is well studied, as is now the basis of exponential functions. Beyond the multivariate Chebyshev polynomial obtained as tensor products of univariate Chebyshev polynomials, the theory of root systems allows to define a variety of generalized multivariate Chebyshev polynomials that have connections to topics such as Fourier analysis and representations of Lie algebras. We present a deterministic algorithm to recover a function that is the linear combination of at most r such polynomials from the knowledge of r and an explicitly bounded number of evaluations of this function.

Estimating plant uptake of soil water has been a persistent problem in process-based earth system models (ESMs). Initially ignored altogether, plant access to soil water was long modelled with heuristic approaches at large scales. These formulations are currently being replaced as ESMs begin to incorporate more detailed plant hydraulics schemes based on the soil-plant-atmosphere continuum concept. While the new schemes greatly improve mechanistic description of aboveground plant hydraulics, they have given rise to various issues belowground, from excessive hydraulic redistribution to numerical instability. As detailed 3D descriptions of root systems and water flow equations on the soil-root domain have been established, the key challenge is how to scale them up to relevant scales, reducing computational cost to a trivial level without loss of accuracy. Here, we set out a mathematical framework that incorporates recent advances in this area and allows us to relate them to each other. Comparing and contrasting different models, formulated in a novel matrix form of the water flow problem in the root system, allows us to make inferences about their suitability for use in upscaling. We are able to show how to avoid discretization error in the upscaled root scheme, as well as which upscaling method offers full generality, and which yields the computationally simplest forms. These theoretical results are fully supported by numerical simulations of fully explicit 3D root systems and their upscaled versions. Improved performance of the upscaled models is also demonstrated in an application to field data from the Wind River Crane flux tower site (reduced model bias, root mean squared error, and increased robustness of fitted parameters). Root water uptake equations can now be scaled up without discretization error for arbitrary root systems. The chief remaining source of error is soil moisture heterogeneity within discretized soil elements where it is assumed uniform by any given model (e.g. within each vertical layer). The main task for future work thus becomes to achieve a correspondingly accurate description for soil moisture heterogeneity. Some of the upscaling approaches compared here offer hints at potential next steps in this direction.

Background: The root system plays a major role in plant growth and development and root system architecture is reported to be the main trait related to plant adaptation to drought. However, phenotyping root systems in situ is not suited to high-throughput methods, leading to the development of non-destructive methods for evaluations in more or less controlled root environments. This study used a root phenotyping platform with a panel of 20 japonica rice accessions in order to: (i) assess their genetic diversity for a set of structural and morphological root traits and classify the different types; (ii) analyze the plastic response of their root system to a water deficit at reproductive phase and (iii) explore the ability of the platform for high-throughput phenotyping of root structure and morphology. Results: High variability for the studied root traits was found in the reduced set of accessions. Using eight selected traits under irrigated conditions, five root clusters were found that differed in root thickness, branching index and the pattern of fine and thick root distribution along the profile. When water deficit occurred at reproductive phase, some accessions significantly reduced root growth compared to the irrigated treatment, while others stimulated it. It was found that root cluster, as defined under irrigated conditions, could not predict the plastic response of roots under drought. Conclusions: This study revealed the possibility of reconstructing the structure of root systems from scanned images. It was thus possible to significantly class root systems according to simple structural traits, opening up the way for using such a platform for medium to high-throughput phenotyping. The study also highlighted the uncoupling between root structures under non-limiting water conditions and their response to drought. Made available in DSpace on 2020-11-10T09:17:39Z (GMT). No. of bitstreams: 1 rice-2020.pdf: 1699263 bytes, checksum: 89a34ce1933139dba85364736d3673ce (MD5) Previous issue date: 2020

Coastal areas are at increasing risk from flooding and erosion due to coastal development and climate change. Seagrass meadows, like other coastal ecosystems, can stabilise sediments, indirectly reducing coastal erosion. There is evidence that seagrass can reduce both the erosion of seabeds and lateral erosion of seagrass cliffs. However, these previous studies have only considered seagrass species whose below-ground biomass form dense root mats. This study aimed to investigate whether Enhalus acoroides, a species which does not form root mats, reduces lateral erosion rates of seagrass cliffs. To do this, samples of E. acoroides collected in sandy sediments within Xincun Bay China were transplanted into a wave flume. Lateral erosion rates were measured under exposure to waves for five cliff heights over 1 h. There was an interaction between cliff height and time on the rate of erosion, with higher erosion rates earlier in the experiment for larger cliff heights. The cores with the E. acoroides persisted longer than unvegetated cores, regardless of cliff height, but this result was not assessed statistically due to constraints in the analyses. The below-ground biomass of E. acoroides samples in this study was higher than values previously reported in the literature. Overall, these results suggest that non-dense root-mat forming seagrass species may not provide equivalent sediment stabilisation as dense root-mat-forming species, likely due to the reduced binding structure of the roots in species such as Enhalus.

In most ecosystems, plant roots from different species decompose in mixtures and in the presence of living roots; however much root decomposition research has focused on how roots of individual species or artificial mixtures decompose in the absence of living plants. We thus examined two poorly studied components of root litter decomposition: 1) whether decomposition of root mixtures can be predicted from the sum of the decomposition rates of each component species and 2) how living plants influence rates of root decomposition. Decomposition rates of roots from three perennial herbaceous Mediterranean species grown in monocultures and in two- and three-species mixtures were determined after a one-year incubation period under their living community and in non-vegetated soil (bare soil). Soil respiration in the presence of glucose (substrate induced respiration, SIR) was measured in each plant community and in bare soil. Decomposition rates of root mixtures cannot be predicted from decomposition rates of the component species, both additive and non-additive effects were observed; the presence of low quality roots of Carex humilis in mixtures strongly negatively influenced root decomposition. The presence of living plants stimulated root decomposition in monocultures and two-species communities, likely through an enhanced microbial activity (SIR) under plant communities. This study highlights that root decomposition cannot be predicted from decomposition rates of the component species and is more influenced by endogenous factors or root litter functional composition than by plant community composition.

Made available in DSpace on 2018-12-11T17:30:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-05-01 Agence Nationale de la Recherche Centre de Coopération Internationale en Recherche Agronomique pour le Développement Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Universidade de São Paulo Background and aims: Comparing root functioning under contrasting rainfall regimes can help assessing the capacity of plant species to cope with more intense and frequent drought predicted under climate change context. While the awareness of the need to study the whole root system is growing, most of the studies of root functioning through rhizosphere analyses have been restricted to the topsoil. Our study aimed to assess whether the depth in the soil and the rainfall amount affect root functioning, and notably the fate of nutrients within the rhizosphere. Methods: We compared pH and nutrient availability within the rhizosphere and bulk soil along a 4-m deep soil profile in a 5-year-old eucalypt (Eucalyptus grandis) plantation under undisturbed and reduced rainfall treatments. Results: The exchangeable K concentration and the pH of the bulk soil were not influenced by the reduced rainfall treatment. By contrast, the H3O+ concentration in the rhizosphere was significantly greater than that of the bulk soil, only in the reduced rainfall plot. The concentrations of exchangeable K in the rhizosphere were significantly larger than those of the bulk soil in both treatments but this difference was higher in the reduced rainfall plot, notably below the depth of 2 m. Both exchangeable K and H3O+ concentration significantly increased within the rhizosphere in the reduced rainfall treatment at soil depth down to 4 m. Conclusions: The amount of K brought to the roots by mass flow was estimated and could not explain the observed increase in exchangeable K concentration within the rhizosphere. A more likely explanation was root-induced weathering of K-bearing minerals, partly related to enhanced rhizosphere acidification. Our results demonstrate that root functioning can be considerably altered as a response to drought down to large depths. CIRAD UMR Eco&Sols, 2 Place Viala INRA UMR Eco&Sols, 2 Place Viala FCA UNESP LCF ESALQ CENA ESALQ FCA UNESP Agence Nationale de la Recherche: ANR-13-AGRO-0005 FAPESP: 2013/25998-4

Background and Aims Root anchorage function is crucial for tree survival as most trees are exposed to recurrent wind throughout their lifespan. Trees exhibit a large variability of root system architecture (RSA) due genetic and environmental factors. This study aims to understand the links between RSA and tree stability. Methods A 3D biomechanical model was used to simulate tree overturning. To capture the variability of sinker RSA, fourteen virtual root patterns were created from an ensemble average of measured Pinus pinaster root systems. Root virtual patterns and tree-pulling simulations were verified against experimental data. Results The model predicts realistic tree anchorage strength, root stress, and failure patterns. Only a few root components contribute significantly to anchorage strength. The taproot contributes the most to anchorage rigidity, representing 61 % of the anchorage strength. The windward roots failure drives ultimate anchorage failure, representing 25 % of the anchorage strength. Simulations show that root secondary thickening induces higher anchorage rigidity and increases anchorage strength by 58 %. Conclusions This innovative approach appears promising for describing tree stability and its acclimation to external constraints.

A practical and cost-effective destructive sampling method for estimating above and belowground biomass of Corymbia citriodora subspecies variegata grown in plantations is described. The methodology includes details on selecting sample trees, weighing tree components in the field, excavating root systems and obtaining fresh weights and laboratory analyses of components to determine oven dry weights. The development of these sampling procedures is a basic step towards successful, consistent collection of biomass data in 18-20 years old plantation forests. This methodology was developed for eucalypt hardwood timber plantations in Queensland, Australia. However, these procedures can be applied to plantations elsewhere as well as to trees in native forest environments with minor modifications. The methodology developed for field sampling of the tree components and the derivation of allometric relationships for predicting individual tree biomass (above and belowground) highlighted the following:•Accurate quantification of above and belowground biomass of eucalypts.•Description of measured variables for developing allometric relationships.•Integration of field and laboratory measurements to streamline data collection., Graphical abstract Image, graphical abstract

National audience; Phénotypage haut débit de l'architecture du système racinaire du blé. Journée scientifique de l'Association des Sélectionneurs Français

Sugarcane root systems are poorly studied and understood due to the perennial nature, tall stature, and the long cropping cycle. Whilst some field studies gave insights into sugarcane root traits, there is no detailed description of root and root system traits available. The objectives of our work were to establish a baseline of sugarcane root trait values that will serve for future studies, and to characterise the degree of root system resilience when restricting tiller number. We first conducted an initial screening for root trait diversity on a collection of twenty cultivars representative of sugarcane breeding from 1930 to now. Then we investigated the effect of reduced tillering, via manual de-tillering, on the plant root and root system traits of five varieties grown under optimal conditions in a glasshouse for 1700 °Cd. In addition to establishing baseline means and variation for sugarcane root trait values that could serve as a reference for crop models, we demonstrated that the sugarcane root mass fraction was extremely resilient to drastic reduction in tiller number. Restricted plants were effectively maintaining their root system configuration (opening angle) by dramatically increasing the number of nodal roots produced per tiller as well as maximizing total root length by increasing the specific root length. Using this knowledge of sugarcane root traits in combination with the specific agronomic constraints for sugarcane will now underpin the development of a root system ideotype for sugarcane to enable targeted root trait selection for improving crop productivity.

Le développement du système racinaire résulte de l’équilibre entre les interactions physiques et chimiques avec le sol et la perception de conditions environnementales plus globales comme, par exemple, la gravité terrestre qui permet à la racine de percevoir la verticale. La morphogenèse du système racinaire est en particulier conditionnée par l’apex racinaire qui oriente la croissance longitudinale des racines. L’apex racinaire est connu pour être une zone influencée par les propriétés chimiques et mécaniques de son environnement. Cependant, la rhéologie de l’apex racinaire (lien entre ses déformations et les contraintes auxquelles il est soumis) lors de la progression des racines demeure mal connue. Étudier cette rhéologie nécessite l’observation de la déformation à l’échelle cellulaire de l’apex racinaire dans des conditions in-vivo au sein de milieux aux propriétés mécaniques mesurables et contrôlables. Pour ce faire nous avons développé un microscope à feuillet de lumière (SPIM : Selective Plane Illumination Microscopy) en nous appuyant sur le projet OpenSPIM qui propose des plans sous licence libre pour sa construction. Cette technique d’imagerie par fluorescence connait un gain d’intérêt depuis une dizaine d’années du fait de ses capacités d’imagerie 3D in-vivo permises par une vitesse d’acquisition rapide accompagnée d’une faible phototoxicité. Nous présenterons ici cette technique de microscopie, la construction de cet instrument et ce qu’il apporte pour l’étude de la croissance des racines in-vivo.

EnglishUntil few years ago there were limited options of apple rootstocks commercially available for Brazilian growers; although, new series of Geneva® rootstocks introduced recently present desirable features such as vigor control and wider lateral branch angle. On the main apple producing regions of Brazil, intermittent rainfall eventually occurs and waterlogged condition is frequent especially in high clay oxisols; in addition, little is known about the tolerance of rootstocks M.9, Marubakaido/M.9 interstock, G.202, G.213 and G.814 to waterlogging. Thus, the objective of this experiment was to evaluate the tolerance of these rootstocks to short-term waterlogging on root and aerial parameters. Potted ‘Maxi Gala’ apple plants were kept under 48 hours of waterlogging weekly throughout 19 weeks to be compared with a normal hydric condition control. The evaluated variables were: leaf, stem and root dry matter, number and length of new root emission, and number of leaves, mean leaf size and chlorophyll content. Rootstocks G.202, G.814 and Marubakaido/M.9 interstock presented more tolerance to waterlogging, and the main defense mechanism was the emission of new adventitious roots. Key words: flood; hypoxia; resilience; root system. portuguesAte pouco tempo, haviam poucas opcoes de porta-enxertos de macieira disponiveis comercialmente para produtores brasileiros. Contudo, com a nova serie de porta-enxertos Geneva® introduzidos recentemente, caracteristicas desejaveis foram apresentadas como, controle de vigor e ângulo de ramo aberto. Nas principais regioes produtoras de maca no Brasil, chuvas intermitentes ocorrem eventualmente levando muitas areas ao encharcamento, especialmente em locais com latossolos com elevados teores de argila. Em adicao, pouco se sabe sobre a tolerância dos porta-enxertos M.9, Marubakaido com inter-enxerto de M.9, G.202, G.213 e G.814 ao encharcamento. Assim, o objetivo deste experimento foi avaliar a tolerância destes porta-enxertos ao encharcamento temporario atraves de parâmetros de raiz e parte aerea. Macieiras ‘Maxi Gala’, cultivadas em vasos, foram mantidas sob encharcamento semanalmente durante 48 horas por 19 semanas, para serem comparadas com o controle em condicao hidrica normal. As variaveis analisadas foram: massa seca das folhas, caule e raiz, comprimento e numero de raizes novas, numero de folhas, tamanho de folha e teor de clorofila. Os porta-enxertos G.202, G.814 e Marubakaido com filtro de M.9 apresentaram maior tolerância ao encharcamento, sendo que o principal mecanismo de defesa para isso foi a maior emissao de raizes adventicias novas. Palavras-chave: alagamento; hipoxia; resiliencia; sistema radicular

International audience; Rapid adjustment of plant physiology and development to external fluctuations is critical for sessile organism, giving a singular interest to network signaling controlling these mechanisms. Among many adaptation processes, root plasticity is primordial to optimize nutrient acquisition but relies on a complex network integrating local and systemic (root shoot) signaling. Indeed, locally, plants invest resource in soil area where nutrients are available and systemically they adjust nutrient acquisition to the whole plant demand.Our main goal is to decipher systemic signaling underlying the perception of nitrate heterogeneous provision, in Arabidopsis. Using the split-root system, in which physically isolated root systems of the same plant were challenged with different environments, we previously demonstrated that cytokinin biosynthesis constitutes one critical component of root-shoot-root communication. By combining the use of cytokinin mutants with hormone measurements, transcriptomic analysis, nitrate uptake assays, and root growth measurements, we show that root to shoot trans-zeatin (tZ) translocation is likely crucial for long distance signaling controlling rapid sentinel gene regulation and long-term functional acclimation to heterogeneous nitrate supply. Interestingly, shoot transcriptome profiling revealed that glutamate/glutamine metabolism is likely a target of tZ root-to-shoot translocation, prompting an interesting hypothesis regarding shoot-to-root communication. Finally, this study also highlights tZ-independent pathways triggered by variation into nitrogen supply.

Background Tree allometric equations are critical tools for determining tree volume, biomass and carbon stocks. However, there is a lack of species-specific biomass equations for juvenile trees of many of New Zealand’s indigenous species. The aim of this study was to provide allometric equations for total above- and below-ground biomass and total root biomass and length for eight common evergreen conifer and broadleaved species. Methods In a plot-based field trial, growth metrics of conifers Prumnopitys taxifolia (matai), Agathis australis (kauri), Prumnopitys ferruginea (miro), Podocarpus totara (totara), Dacrycarpus dacrydioides (kahikatea) and Dacrydium cupressinum (rimu) and broadleaved species Alectryon excelsus (titoki) and Vitex lucens (puriri) were measured annually. These species were selected based on their potential role as a long-term solution for mitigating erosion in areas of marginal land proposed for new afforestation/reforestation and as an important carbon (C) sink. Results Root collar diameter (RCD) provided the best fit for tree height, total above-ground biomass (AGB) and total below-ground biomass (BGB), and all regressions were highly significant (P = 0.001). Most species showed significant increases in annual growth and, by year 5, the BGB ranged between 21 and 42% of total biomass and decreased with increasing plant age. Of the conifers, Podocarpus totara had the greatest mean maximum root spread (2.2 m) exceeded only by the broadleaved Vitex lucens (2.5 m). For all species, and in each year of the trial, 100% of the BGB remained confined to within 0.5 m of the ground surface. With the exception of Vitex lucens and Podocarpus totara, > 90% of the total root length remained within a 0.5-m radius of the root bole. The species-specific mean tree biomass of 5-year-old plants ranged from 0.32 to 4.28 kg plant−1. A mixed-species forest established at 1000 stems per hectare (spha), consisting of 200 of each of the best performed of the trialled species, would amass ~ 2.3 t ha−1 of biomass and a forest carbon stock of 3.8 t CO2 ha−1 within 5 years. Conclusions Inter-species differences in the allocation of BGB and AGB appeared to be age dependent. The root-growth metrics of these common indigenous forest species, as candidates for erosion control, have improved our understanding of their potential usefulness for stabilising marginal land. Whole-plant biomass of juvenile trees will greatly improve the accuracy of current estimates of forest carbon stocks for proposed new areas of indigenous afforestation/reforestation.

Description of the subject. The present study focuses on the description of the allelopathic interactions between wild and crop species that may occur in a given ecosystem. Objectives. The objective is the evaluation of the allo- and autoinhibition activity of root exudates of barley (Hordeum vulgare L. subsp. vulgare) and great brome (Bromus diandrus Roth.) seedlings by water-soluble allelochemicals. Method. The allelopathic activities of five Tunisian barley genotypes (modern varieties and landraces), one Saudi Arabian barley landrace and great brome were assessed using a modified laboratory bioassay named "seedling-after-seedling agar method". Results. The barley or the great brome reduced, to a greater extent, the root growth compared to the shoot growth of receiver species. The response of the root system architecture of the great brome towards barley root exudates was studied in detail. All the measured root traits were highly sensitive to the presence of barley. In our conditions, the allelopathic activity of barley root exudates had no apparent relationship with the size of the root and a prominent action of genetic determinants in the allelopathic potential between genotypes is proposed. The alloinhibitory activity of barley or great brome root exudates deferred between the receiver species but was always higher than the autoinhibition potential. The autoinhibition in barley proved to depend on whether the genotypes used as donor and receiver are identical or different, suggesting a specific interaction of allelochemicals with the receiver plant. These molecules seem to be the main actors in the allelopathic barley potential as external factors such variations of pH have no evident relevance in the inhibition process. Conclusions. Barley and great brome exude molecules in their surroundings. This affects the growth of the receiver plants, suggesting that these compounds might contribute to the plant community dynamics.

International audience; This paper shows that for any Lie group G whose Lie algebra L is the split real form of a complex simple Lie algebra, and for any arbitrary root ź, there exists a Cartan decomposition of L, related to ź, which characterizes some controllability properties by using the adjoint orbits of sl(2, ź). For a class of invariant control systems evolving on G, it is proved that the necessary full rank condition for controllability is also sufficient.

The study, characterization, observation, and quantification of plant root growth and root systems (Rhizometrics) has been and remains an important area of research in all disciplines of plant science. In the horticultural industry, a large portion of the crops grown annually are grown in pot culture. Root growth is a critical component in overall plant performance during production in containers, and therefore it is important to understand the factors that influence and/or possible enhance it. Quantifying root growth has varied over the last several decades with each method of quantification changing in its reliability of measurement and variation among the results. Methods such as root drawings, pin boards, rhizotrons, and minirhizotrons initiated the aptitude to measure roots with field crops, and have been expanded to container-grown plants. However, many of the published research methods are monotonous and time-consuming. More recently, computer programs have increased in use as technology advances and measuring characteristics of root growth becomes easier. These programs are instrumental in analyzing various root growth characteristics, from root diameter and length of individual roots to branching angle and topological depth of the root architecture. This review delves into the expanding technologies involved with expertly measuring root growth of plants in containers, and the advantages and disadvantages that remain.

High copper (Cu) soil contents, due to the continuous vineyard application of Cu fungicides throughout the years, may impair the growth of the shoot and modify the structure of the root system. The current study aimed to investigate the threshold levels of available Cu in the soil causing toxicity effects in young grapevine plants of ‘Red Niagara’ cultivated in clay soils. Grapevine plantlets were cultivated in pots containing vineyard devoted soils with increasing contents of available Cu (25, 80, 100 and 165 mg kg?1 ), for 53 days. Photosynthesis and transpiration rates, and the quantum yield of photosystem II (Fv/Fm) were evaluated during the cultivation period. At the end of the experiment, the plant nutrient and leaf chlorophyll were determined, along with the anatomical analysis of the root system structure and plant dry matter determination. Higher levels of available Cu in the soil increased the apoplastic, symplastic and total fraction of the metal in the roots, reducing the other nutrients, especially in the shoots. Photosynthesis, transpiration rates and Fv/Fm were also reduced. Higher levels of Cu led to anatomical changes in the roots, that increased diameter, number of layers in the cortex, vascular cylinder and total root areas. It also resulted in reduced dry matter production by grapevines. Keywords: Available Cu Net photosynthesis Maximum quantum yield Root diameter Vitis labrusca L Made available in DSpace on 2019-01-11T00:04:58Z (GMT). No. of bitstreams: 1 Highcoppercontentinvineyardsoilspromotesmodi64257cationsin.pdf: 1434017 bytes, checksum: 77453d1f9f03c8da1881ad6ee30af116 (MD5) Previous issue date: 2019-01-09

Nutrient fluctuations are more a rule rather than an exception in the life of sessile organisms such as plants. Despite this constraint that adds up to abiotic and biotic stresses, plants are able to accomplish their life cycle thanks to an efficient signaling network that reciprocally controls nutrient acquisition and use with growth and development. The majority of nutrients are acquired by the root system where multiple local signaling pathways that rely on nutrient-sensing systems are implemented to direct root growth toward soil resources. Moreover, long-distance signaling plays an essential role in integrating nutrient availability at the whole-plant level and adjusting nutrient acquisition to plant growth requirements. By studying the signaling network for single mineral nutrients, several long-distance signals traveling between roots and shoots and taking a diversity of forms have been identified and are summarized here. However, the nutritional environment is multifactorial, adding a tremendous complexity for our understanding of the nutrient signaling network as a unique system. For instance, long-distance signals are expected to support this nutrient cross-talk in part, but the mechanisms are still largely unknown. Therefore, the involvement of possible long-distance signals as conveyers of nutrient cross-talk is discussed here together with approaches and strategies that are now considered to build a picture from the nutrient signaling puzzle.

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http://www.heldermann.de/JLT/JLT28/JLT281/jlt28010.htm; International audience; Let G be a split real connected simple Lie group and S a semigroup of G that contains a subgroup G(α) for an arbitrary root α, isomorphic to SL(2,R). We present a Cartan decomposition of the Lie algebra of G, related to α, invariant by the adjoint action of the Lie algebra sl(2,R) that allows to characterize some properties of the Lie saturate of the semigroup S. We give necessary and sufficient conditions for S to be equal to the whole group G.

Orientador: Rafael Vasconcelos Ribeiro Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia Resumo: As plantas cítricas estão sujeitas à variação sazonal da disponibilidade de água em várias áreas de cultivo e uma estratégia eficaz para amenizar os impactos da escassez de água na citricultura é a utilização de porta-enxertos tolerantes à seca. É importante entender quais características fazem alguns porta-enxertos mais tolerantes que outros para que espécies alternativas com características fenotípicas e fisiológicas semelhantes sejam selecionadas. A redistribuição hidráulica é o movimento passivo de água nas raízes seguindo um gradiente de potencial da água, sendo a água absorvida por raízes em solo úmido e liberada em tecidos em contato com solo seco. Outra estratégia fisiológica é o ajuste osmótico, caracterizado pelo acúmulo ativo de solutos na célula em resposta à redução da disponibilidade de água no ambiente. A redução do potencial osmótico facilita a extração da água em solos secos e mantém o turgor das células. Nesse contexto, os objetivos deste trabalho foram avaliar a redistribuição hidráulica em duas espécies de porta-enxerto, bem como verificar se o ajuste osmótico está associado a este fenômeno. Laranjeiras Valência foram enxertadas com limoeiro Cravo e citrumeleiro Swingle de tal forma que as mudas formadas possuíssem dois sistemas radiculares de porta-enxertos diferentes ou de um mesmo porta-enxerto para simular uma situação em que apenas parte das raízes tinha disponibilidade de água enquanto a outra parte estava sob déficit hídrico. Os experimentos permitiram constatar que as duas espécies realizavam redistribuição de água e que o Cravo possui maior capacidade de enviar água para o lado seco da raiz. A maior habilidade de redistribuir água do limoeiro Cravo em relação ao citrumeleiro Swingle foi associada à maior absorção de água pelas raízes úmidas ocasionada pela diminuição do potencial osmótico. As copas de laranjeira Valência enxertadas sobre limoeiro Cravo também apresentaram sensibilidade estomática à variação da disponibilidade de água, sugerindo que as raízes sob seca sinalizaram para que o fechamento estomático ocorresse mesmo havendo suprimento de água pela parte úmida e a folha estando hidratada. As trocas gasosas da copa enxertada sobre o citrumeleiro Swingle não foram significativamente afetadas pela redução da disponibilidade hídrica, permanecendo com os estômatos abertos durante o período experimental. Quando comparados os porta-enxertos, as modificações fisiológicas e mecanismos descritos levaram à maior resistência do limoeiro Cravo à seca Abstract: Citrus plants are subject to a seasonal variation of water availability in many growing areas, an effective strategy to mitigate the impacts of citrus water scarcity is the use of drought tolerant rootstocks. It is important to understand which characteristics make some rootstocks more tolerant than others so that alternative rootstocks with similar phenotypic and physiological characteristics are selected. Hydraulic redistribution is a passive movement of water in roots following a gradient of water potential, in moist soil sites water is uptaken by roots and then released in tissues in contact with drier soil. Osmotic adjustment is another physiological strategy, characterized by an active cell accumulation of solutes in response to a reduction of water availability in the environment. A reduction in osmotic potential facilitates the extraction of water in dry soils and maintains the cells turgor. In this context, the aims of this work were to evaluate the hydraulic redistribution in two rootstock species, as well as to verify if the osmotic adjustment is associated with this phenomenon. Seedlings of Valencia sweet orange were inarched with Rangpur lime and Swingle citrumelo rootstocks, each seedling had two root systems to simulate a situation where only part of the roots had water availability while the other part was under water limiting conditions. The experiments allowed us to verify that both species redistributed water and that Rangpur lime has greater capacity to send water to the roots under drought. The greater ability to redistribute water of Rangpur lime in comparison to Swingle citrumelo was associated to a greater absorption of water by the moist roots caused by a decrease in osmotic potential. Valencia sweet orange canopies grafted on Rangpur lime also showed a stomatal sensitivity to the variation of water availability, suggesting that roots under drought signaled for stomatal closure even though water was supplied by the moist part and leaves were hydrated. The gas exchanges of the canopy grafted on Swingle citrumelo were not significantly affected by the reduction of water availability, keeping the stomata open during the experimental period. When comparing rootstocks, physiological modifications and mechanisms described led to a greater drought tolerance of Rangpur lime Mestrado Biologia Vegetal Mestra em Biologia Vegetal FAPESP 2016/02199-7 CNPQ 131126/2016-4

International audience; One of the most challenging computer vision problems in the plant sciences is the segmentation of roots and soil in X-ray tomography. So far, this has been addressed using classical image analysis methods. In this paper, we address this soil-root segmentation problem in X-ray tomography using a variant of supervised deep learning-based classification called transfer learning where the learning stage is based on simulated data. The robustness of this technique, tested for the first time with this plant science problem, is established using soil-roots with very low contrast in X-ray tomography. We also demonstrate the possibility of efficiently segmenting the root from the soil while learning using purely synthetic soil and roots.

Orientador: Marcelo Menossi Teixeira Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia Resumo: A cana-de-açúcar é uma cultura de importância econômica mundial, atuando como matéria-prima principalmente na produção de açúcar e etanol. A cultura de cana é afetada por vários tipos de estresses bióticos e abióticos, sendo a seca um dos principais fatores que reduzem a sua produtividade. A seca atua sobre as variedades vegetais de diversas formas, provocando alterações na parte aérea e no sistema radicular. As raízes desempenham um papel importante na manutenção das funções da planta em condições de estresse, de modo que suas propriedades exercem grande influência na resposta à escassez hídrica. Entretanto, o conhecimento acerca das alterações da expressão gênica em raízes de cana sujeitas à seca ainda é muito restrito, embora seja uma etapa importante para a identificação de genes com potencial para a produção de plantas mais tolerantes ao deficit hídrico. Deste modo, este projeto objetivou a identificação de genes modulados por seca em raízes de cana para estudos funcionais empregando plantas transgênicas de Arabidosis thaliana e cana-de-açúcar. Utilizando dados de RNA-Seq de dois cultivares de cana (RB92579 e RB72454) foram selecionados 10 genes potencialmente relevantes nas respostas radiculares frente à condições de seca. Testes de estresse severo e moderado utilizando plantas transgênicas de Arabidopsis e cana-de-açúcar superexpressando alguns desses genes apontaram o envolvimento no mecanismo de tolerância à seca Abstract: Sugarcane is a crop of global economic importance, acting as raw material especially in the production of sugar and ethanol. Sugarcane is affected by various types of biotic and abiotic stresses, and drought is one of the main factors reducing sugarcane productivity. Drought acts on the plant varieties of several ways, causing alterations in shoots and roots. Roots play an important role in the maintenance of plant functions under stress conditions, and their properties have great influence on responses to water scarcity. However, the knowledge on gene expression changes in plant roots subject to drought is still very restricted, although it is an important step for the identification of genes with potential for the production of plants more tolerant to water deficit. Therefore, this project aims to identify genes modulated by drought in sugarcane roots for functional studies using Arabidopsis thaliana and sugarcane transgenic plants. Using RNA-Seq data from two sugarcane cultivars (RB92579 and RB72454) we selected 10 potentially relevant genes in root responses in drought conditions. Severe and moderate stress tests using Arabidopsis and sugarcane transgenic plants overexpressing some of these genes indicated the involvement in drought tolerance mechanisms Doutorado Genética Vegetal e Melhoramento Doutora em Genética e Biologia Molecular FAPESP 2014/26521-0

In his affirmative answer to the Edelman-Reiner conjecture, Yoshinaga proved that the logarithmic derivation modules of the cones of the extended Shi arrangements are free modules. However, all we know about the bases is their existence and degrees. In this article, we introduce two distinguished bases for the modules. More specifically, we will define and study the simple-root basis plus (SRB+) and the simple-root basis minus (SRB-) when a primitive derivation is fixed. They have remarkable properties relevant to the simple roots and those properties characterize the bases.

Carbon isotope composition in respired CO2 and organic matter of individual organs were measured on peanut seedlings during early ontogeny in order to compare fractionation during heterotrophic growth and transition to autotrophy in a species with lipid seed reserves with earlier results obtained on beans. Despite a high lipid content in peanut seeds (48 %) compared with bean seeds (1.5 %), the isotope composition of leaf- and root-respired CO2 as well as its changes during ontogeny were similar to already published data on bean seedlings: leaf-respired CO2 became C-13-enriched reaching -21.5 parts per thousand, while root-respired CO2 became C-13-depleted reaching around -31 parts per thousand at the four-leaf stage. The opposite respiratory fractionation in leaves vs. roots already reported for C-3 herbs was thus confirmed for peanuts. However, contrarily to beans, the peanut cotyledon-respired CO2 was markedly C-13-enriched, and its C-13-depletion was noted from the two-leaf stage onwards only. Carbohydrate amounts being very low in peanut seeds, this cannot be attributed solely to their use as respiratory substrate. The potential role of isotope fractionation during glyoxylate cycle and/or gluconeogenesis on the C-13-enriched cotyledon-respired CO2 is discussed.

The objective of this work was to compare the biomass of fine roots in different physiognomies evaluating the influence of seasonality at the Amazon savannas located in Amapá and Pará States. Soil samples were collected in five positions, from 10 to 50 cm deep. Three points were allocated at typical savanna (Cerrado sensu stricto), 4 at open savanna (Campo Cerrado) and 2 at natural grassland (Campo Limpo). At each point 4 replications were performed. The influence of seasonality was verified only in Campo Cerrado in April (rainfall peak), July (end of rainy season) and October (peak of drought) of 2010 and in January of 2011 (beginning of rainy season). The physiognomies were differentiated by root mass when analyzed under different diametric classes of roots and different depths. The largest mass of fine roots occurred at the peak of the dry season. These results suggest different strategies in finest roots allocation in different physiognomies and soil depths and differences of roots dynamics to increase absorption potential during dry season. Este trabalho objetivou comparar a biomassa de raízes finas em diferentes fisionomias e avaliar a influência da sazonalidade sobre a massa de raízes finas em savanas amazônicas localizadas no Amapá e Pará. Amostras de solos foram coletadas em cinco profundidades, de 10 em 10 cm, em três pontos no Cerrado sensu stricto, quatro no Campo Cerrado e dois no Campo Limpo, com 4 repetições em cada posição. A influência da sazonalidade foi verificada apenas no Campo Cerrado, em abril (pico das chuvas), julho (final das chuvas) e outubro (pico da seca) de 2010 e em janeiro de 2011 (inicio das chuvas). As fisionomias foram diferenciadas pela massa de raízes, quando analisadas nas diferentes classes diamétricas de raízes e nas diferentes profundidades. A maior massa de raízes finas ocorreu no pico da estação seca. Esses resultados sugerem estratégias diferentes das fisionomias na alocação das raízes mais finas em diferentes profundidas do solo e na dinâmica das raízes para aumentar o potencial de absorção durante a seca.

В статье представлен многолетний экспериментальный материал, отра- жающий основные аспекты формирования корневых систем главных древесных пород в защитных лесных насаждениях сухой степи. Установлены приспособительные особенности корневых систем, характер распространения в почвенных горизонтах и их структура в зависимости от условий внешней среды, агротехники и других лесохозяйственных мероприятий. В связи с низкой влагообеспеченностью корнеобитаемого слоя почвы корневые системы тянутся в стороны поля на значительные расстояния и оказывают негативное воздействие на прилегающую территорию – депрессионную зону. Исследования показали, что на территории засушливых областей, где питание лесных полос во многом осуществляется за счет прилегающих полей, важнейшим лесоводственным приемом является снижение общей потребности древостоя в запасе почвенной влаги до уровня, при котором существенно уменьшается амплитуда колебания его влаго- обеспеченности по годам, удовлетворительно растут и формируются устойчивые насаждения. Выявлено, что основные технологические приемы заключаются в уменьшении рядности полос, дифференцировании их породного состава в зависимости от рельефа полей, использования преимущественно засухоустойчивых видов, формирования умеренно ажурного ветроломного профиля и содержания насаждений в режиме лесных экосистем, то есть соблюдением базовых принци- пов степного лесоразведения – обеспечение эффективного влагонакопления в почве отведенной под насаждение полосы, сбережение и экономное расходова- ние почвенной влаги. Полученные данные об особенностях строения корневых систем могут значительно увеличить долговечность и устойчивость защитных лесных насаждений и существенно обеспечить дальнейшее совершенствование методов, технических приемов и других элементов лесоводственных уходов за древостоем., The long-term experimental material reflecting the basic aspects of formation of root systems of the main tree species in protective forest plantings of dry steppe is presented in the article. Adaptive features of root systems, the nature of distribution in soil horizons and its structure depending on environmental conditions, agrotechnics and other forest management measures have been established. Because of the low humidity root layer of soil root systems are drawn to the field over significant distances and have a negative impact on the surrounding area – a depression zone. Studies have shown that in the territory of droughty areas, where forest belts are fed by adjacent fields, the most important silvicultural method is lowering of the general need of a forest stand for an inventory of soil moisture to the level in case of which amplitude of oscillations of its moisture security by years significantly decreases, steady plantings grow satisfactorily and are created. It is revealed that the main processing methods consist in reduction of quantity of strips, differentiation of its structure depending on a relief of fields, use of mainly drought-resistant types, formation of moderately openwork profile, protective from wind, and content of plantings in the mode of forest ecosystems, that is respect for the basic principles of steppe afforestation – ensuring effective moisture accumulation in the soil of the strip which is taken away under planting, saving and an economical expenditure of soil moisture. There were obtained about the features of the structure of root systems can greatly increase the durability and stability of protection forests and to significantly further improve the methods, techniques and other elements of silvicultural treatments for the forest., №221 (2017)

Question: Root biomass distribution and below-ground processes are the main drivers of plant community structure and dynamics in arid rangelands. However, despite their relevance, below-ground plant responses to disturbance regimes remain poorly understood. This knowledge is a pressing issue since most of our ideas derive from extrapolating above-ground ecological theory and data. Here, we asked how domestic grazing management changes (intensification and abandonment) impact on both below-ground species co-occurrence at microsite level (point-richness) in relation to above-ground patterns and below-ground biomass distribution of dominant graminoid species across different soil layers. Location: Patagonian steppe, Argentina. Methods: We sampled and compared ungrazed, moderately grazed and intensively grazed steppes. We evaluated below- and above-ground point-richness (microsite level: 6-cm diameter), as well as total and specific root biomass in the top 20 cm of soil along 50-m transects in commercial paddocks. Results: We found independence between fine-scale below- and above-ground responses. Below-ground point-richness was at least three times higher than above-ground point-richness. Besides, below-ground point-richness decreased from 4.2 species in ungrazed sites to 3.4 species in intensively grazed ones. Neither grazing intensification nor abandonment changed total root biomass, although intensification changed the root biomass composition, reducing preferred and increasing non-preferred grass species. Strikingly, below-ground point-richness and total root biomass did not differ between microsites covered and not covered by vegetation. This pattern was not affected by grazing. Conclusions: Our findings showed a higher degree of fine-scale below-ground species co-occurrence than above-ground in this Patagonian steppe. The intensification of grazing slightly decreased below-ground species co-occurrence and changed root composition (species abundance), although grazing management did not modify the high degree of independence between below- and above-ground structure. Even though intensive grazing markedly decreases above-ground biomass, total below-ground biomass does not vary along a wide range of grazing conditions. In general, most of our knowledge about vegetation responses to grazing is based on above-ground information, assuming that below-ground patterns and processes are analogous to those above-ground. This study suggests that below- and above-ground community structure at fine-scale are not strongly correlated and they can be differentially affected by grazing. Fil: Oñatibia, Gastón Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Reyes, María Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía; Argentina Fil: Aguiar, Martin Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía; Argentina

Cilj ovog rada je implementacija Freudenthalove formule za sve proste Liejeve algebre. Opisane su osnovne definicije i svojstva potrebna za razumijevanje Liejevih algebri. Također je opisan i način reprezentacije Lijeve algebre te različitosti između istih. Rad je zaključen Freudenthalovom formulom te kratkim primjerom računanja multipliciteta. The main goal of this final thesis is implementation of Freudenthal’s formula for simple Lie algebra. The basic definitions and features needed to understand Lie algebra, representation of Lie algebra and differences between them are described. Thesis is concluded with Freudenthal’s formula itself and short example of multiplicity calculation.

We classify all non-abelian groups G such that there exists a pair (V,W) of absolutely simple Yetter-Drinfeld modules over G such that the Nichols algebra of the direct sum of V and W is finite-dimensional under two assumptions: the square of the braiding between V and W is not the identity, and G is generated by the support of V and W. As a corollary, we prove that the dimensions of such V and W are at most six. As a tool we use the Weyl groupoid of (V,W)., Comment: 21 pages. Final version. Accepted for publication in Journal of Group Theory

28 pags.- 4 Tabls.- 4 Figs. The definitive version is available at: https://www.sciencedirect.com/science/journal/03418162, The accurate measurement of soil infiltration rates is a challenging task in hydrological studies, as they are governed by complex interactions between the plant and soil components. To explore the effects of plant roots and soil moisture (SM) on infiltration process, an automatic measurement system based on a point source device was used to determine infiltration rates at different cultivated grasslands (leguminous, gramineous and mixed) in an arid region of China. The results showed that SM and plant roots significantly affected the infiltration process at different stages in the three grasslands. The soil infiltration rates were negatively correlated to SM, but a positive correlation was observed with the below-ground biomass (BGB). SM was the main factor influencing the infiltration rates in the initial stage of infiltration, whereas both SM and BGB determined the steady-state infiltration rates. The influence of the combined effects of SM and plant roots decreased over infiltration time. The decreased rate of determining coefficient showed that SM was more influent than plant roots. These results may contribute to interpret the observed higher soil infiltration capacity in the leguminous grasslands than in the gramineous and the mixed grasslands, and were conducive to better understand the effects of plant and soil properties on infiltration processes in arid areas., This research was funded by the Projects of the National Natural Science Foundation of China (NSFC 41722107), the Light of West China Program of the Chinese Academy of Sciences (XAB2015A04; XAB2018B09), the Fundamental Research Funds for the Central Universities (2452018086; 2452019187), and the Youth Talent Plan Foundation of the Northwest A&F University (2452018025).

Moringa oleifera Lam. (Moringa), Jatropha curcas L. (Jatropha), and Ricinus communis L. (Ricinus) are oily species known by their capability to grow in tropical and subtropical lands. However, there are no studies comparing their growth and recovery capabilities after root pruning and transplant. The purpose of this research was to compare and analyze propagation, growth, and recovery performance of these species after root pruning and transplant. We sowed 100 seeds per species and monitored their survival and growth during a 63-day period, after this, we uprooted the plants and pruned their roots 4.0 cm from their base and transplanted them. We monitored their recovery over 83 days, and then uprooted plants and measured above- and belowground data, digitized their roots in three dimensions, and calculated biomass fractions. With this information, we established allometric equations to estimate biomass fractions and root distribution models. Results indicated that Ricinus had the highest propagation capabilities. Jatropha and Ricinus had similar recovery after root pruning and transplant. Moringa had the lowest propagation and recovery from transplant. Concerning belowground data, root pruning increased root density more than three times in Moringa, four times in Ricinus, and six times in Jatropha. Nevertheless, the three species maintained natural root trays. Ricinus had the longest and thinnest roots and the highest number of branches, followed by Jatropha, and finally Moringa, with the smallest quantity and the shortest and thickest roots. We concluded that the three species recovered well from root pruning and transplant, with improved root structure upon applying these practices.