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The influence of the plant density to the photosynthesis process was studied during the ontogenesis in the sorts Sevinj and Amiri-600 of the potato. So the plant density influence significantly to the leaf surface size, chlorophyll content and photosynthesis potential. The leaf surface area, the increase of the photosynthesis potential and in the amount of the chlorophyll in the leaf were researched during the growth and development of the plant. It was determined that the photosynthetic indicators are higher during the flowering period. [ABSTRACT FROM AUTHOR]

The effects of grazing and mowing on the ontogenetic structure of cereal population of Dactylis glomerata L., Festuca pratensis Huds., Phleum pratense L., Deschampsia cespitosa (L.) P. Beauv., Alopecurus pratensis L., Elytrigia repens (L.) Nevski., Bromopsis inermis (Leyss.) Holub. were studied in the floodplains meadows of Psel River and Sula River (Forest-Steppe zone of the North-Eastern Ukraine). It was established with the decrease in the abundance (projective cover) of cereal grasses significant changes in the ontogenetic structure of populations occurred simultaneously on the pasture and mowing gradients. Grazing caused deeper transformation of the population structure of meadow grass than moving. The experimental results confirmed that the systematic implementation of geobotanical and population monitoring of meadow lands can be the advisable tool for organizing their optimal use and successful management. This will allow making corrections to the technology of using pastures and hayfields in order to prevent their degradation. [ABSTRACT FROM AUTHOR]

The architecture of plants responds to endogenous processes and to the influence of environmental factors. The allometric study of architecture has been a challenge for biology. We define a new finite (Hausdorff) dimension of plants, that considers both the aerial part and the roots, and compute examples. This new finite dimension was introduced recently and, in contrast to the classical Hausdorff dimension, is not zero on finite sets. We propose the finite dimension, as a function of time, as a "signature" of the plant or root. Our first results suggest that the signature is specific to each plant species and its growth period, and constitutes an objective metric that allows to study its ontogenesis in detail. [ABSTRACT FROM AUTHOR]

Stomata play a critical ecological role as an interface between the plant and its environment. Although the guard‐cell pair is highly conserved in land plants, the development and patterning of surrounding epidermal cells follow predictable pathways in different taxa that are increasingly well understood following recent advances in the developmental genetics of the plant epidermis in model taxa. Similarly, other aspects of leaf development and evolution are benefiting from a molecular–genetic approach. Applying this understanding to extinct taxa known only from fossils requires use of extensive comparative morphological data to infer 'fossil fingerprints' of developmental evolution (a 'palaeo‐evo‐devo' perspective). The seed‐plant order Bennettitales, which flourished through the Mesozoic but became extinct in the Late Cretaceous, displayed a consistent and highly unusual combination of epidermal traits, despite their diverse leaf morphology. Based on morphological evidence (including possession of flower‐like structures), bennettites are widely inferred to be closely related to angiosperms and hence inform our understanding of early angiosperm evolution. Fossil bennettites – even purely vegetative material – can be readily identified by a combination of epidermal features, including distinctive cuticular guard‐cell thickenings, lobed abaxial epidermal cells ('puzzle cells'), transverse orientation of stomata perpendicular to the leaf axis, and a pair of lateral subsidiary cells adjacent to each guard‐cell pair (termed paracytic stomata). Here, we review these traits and compare them with analogous features in living taxa, aiming to identify homologous – and hence phylogenetically informative – character states and to increase understanding of developmental mechanisms in land plants. We propose a range of models addressing different aspects of the bennettite epidermis. The lobed abaxial epidermal cells indicate adaxial–abaxial leaf polarity and associated differentiated mesophyll that could have optimised photosynthesis. The typical transverse orientation of the stomata probably resulted from leaf expansion similar to that of a broad‐leaved monocot such as Lapageria, but radically different from that of broad‐leafed eudicots such as Arabidopsis. Finally, the developmental origin of the paired lateral subsidiary cells – whether they are mesogene cells derived from the same cell lineage as the guard‐mother cell, as in some eudicots, or perigene cells derived from an adjacent cell lineage, as in grasses – represents an unusually lineage‐specific and well‐characterised developmental trait. We identify a close similarity between the paracytic stomata of Bennettitales and the 'living fossil' Gnetum, strongly indicating that (as in Gnetum) the pair of lateral subsidiary cells of bennettites are both mesogene cells. Together, these features allow us to infer development in this diverse and relatively derived lineage that co‐existed with the earliest recognisable angiosperms, and suggest that the use of these characters in phylogeny reconstruction requires revision. [ABSTRACT FROM AUTHOR]

Weaning marine fish larvae from live prey to a dry microdiet is an important step towards optimizing the commercial production, but early weaning is constrained by the lack of sufficient digestive enzymes at first feeding. This study quantified the activity of five digestive enzymes throughout the larval period of pigfish (Orthopristis chrysoptera [L.]) to assess ontogenetic changes in digestive abilities, and then trials were conducted that determined the optimal time for weaning. The activity of all digestive enzymes was low or undetectable at first feeding (3 days post hatching, dph; 2.5 mm standard length, SL). A substantial increase in activity occurred at 5.7 mm SL (17 dph), 6.9 mm SL (21 dph), 7.7 mm SL (23 dph), 8.4 mm SL (25 dph) and 11.2 mm SL (30 dph) for bile salt‐dependent lipase, trypsin, chymotrypsin, amylase and acid protease respectively. During the weaning experiment, larvae were co‐fed live prey and microdiet beginning 15 dph (4.8 mm SL). Live prey was withdrawn from the diet at 24, 28, 32 or 36 dph, with the control receiving live prey and microdiet throughout (to 43 dph). There were no significant differences in mean final SL among treatments, but survival was significantly lower when larvae were weaned at 24 dph compared to 32–43 dph. Based on the digestive enzyme activity and survival, weaning larval pigfish at 32 dph (11.7 mm SL) when reared at 24°C is recommended. [ABSTRACT FROM AUTHOR]

We quantified seasonal CO2 assimilation capacities for seven dominant vascular species in a wet boreal forest peatland then applied data to a land surface model parametrized to the site (ELM-SPRUCE) to test if seasonality in photosynthetic parameters results in differences in simulated plant responses to elevated CO2 and temperature. We collected seasonal leaf-level gas exchange, nutrient content and stand allometric data from the field-layer community (i.e. Maianthemum trifolium (L.) Sloboda), understory shrubs (Rhododendron groenlandicum (Oeder) Kron and Judd, Chamaedaphne calyculata (L.) Moench. Kalmia polifolia Wangenh. and Vaccinium angustifolium Alton.) and overstory trees (Picea mariana (Mill.) B.S.P. and Larix laricina (Du Roi) K. Koch). We found significant interspecific seasonal differences in specific leaf area, nitrogen content (by area; Na) and photosynthetic parameters (i.e. maximum rates of Rubisco carboxylation (V cmax25°C), electron transport (J max25°C) and dark respiration (R d25°C)), but minimal correlation between foliar Na and V cmax25°C, J max25°C or R d25°C, which illustrates that nitrogen alone is not a good correlate for physiological processes such as Rubisco activity that can change seasonally in this system. ELM-SPRUCE was sensitive to the introduction of observed interspecific seasonality in V cmax25°C, J max25°C and R d25°C, leading to simulated enhancement of net primary production (NPP) using seasonally dynamic parameters as compared with use of static parameters. This pattern was particularly pronounced under simulations with higher temperature and elevated CO2, suggesting a key hypothesis to address with future empirical or observational studies as climate changes. Inclusion of species-specific seasonal photosynthetic parameters should improve estimates of boreal ecosystem-level NPP, especially if impacts of seasonal physiological ontogeny can be separated from seasonal thermal acclimation. [ABSTRACT FROM AUTHOR]

Highlights • The ontogenetic analysis of the root epidermis revealed the presence of a uniseriate epidermis in all taxa. • The protodermis presents exclusively anticlinal divisions. Epidermal cells also undergo solely anticlinal divisions. • The ontogenetic study of the root epidermis shows a new insight into it was believed to be velamen. Abstract The anatomy of Bromeliaceae roots has attracted the attention of researchers for a long time. Several authors have described them by highlighting characters associated with mechanisms of water uptake, water retention and adaptation to the environment. In this context, the dermal tissue is frequently mentioned, being described by different authors as uniseriate or pluriestratified epidermis, or even as velamen. In the present study we analyzed the apical meristem region of adventitious roots of nine species belonging to the Pitcairnioideae, Bromelioideae and Tillandsioideae subfamilies. The goal of this study was to elucidate the ontogenetic origin of the tissue referred by several authors as velamen. The root anatomy of analyzed species showed characteristics shared by all taxa, such as the presence of uniseriate epidermis, parenchymal cortex, idioblasts and air channels, as well as a polyarch vascular cylinder. The ontogenetic analysis of the root epidermis carried out in this study enabled us to clarify issues related to the anatomy of this organ that were previously unknown. Our analysis revealed the presence of a uniseriate epidermis in all analyzed taxa in this study, thus increasing the knowledge about the root anatomy of the family. [ABSTRACT FROM AUTHOR]

Background and Aims Fleshy structures that promote biotic dispersal by ingestion have evolved many times in seed plants. Within the yew family Taxaceae sensu lato (six genera, including Cephalotaxus), it remains controversial whether the characteristic fleshy structure surrounding the seed is interpreted as a novel outgrowth of the base of the ovule (i.e. an aril) or a fleshy seed coat that is entirely derived from the integument (i.e. a sarcotesta). This paper presents a detailed study of both wild-type and teratological seed cones of Pseudotaxus chienii, including morphology, anatomy and ontogeny. Methods Wild-type and teratological seed cones were investigated with the classical paraffin technique and subsequent astrablue/safranin staining and scanning electron microscopy. Key Results The wild-type seed cone of Pseudotaxus possesses a fleshy white aril that is cup-like and not entirely fused to the seed. In the teratological seed cones investigated, the aril was bilobed and consisted of two free halves. In both wild-type and teratological cones, the aril was initiated as two lateral primordia in a transverse plane, but in wild-type cones the two primordia became extended into a ring primordium, which grew apically, leading to the cup-like shape. The teratological seed cones lacked a ring primordium and the two lateral aril lobes remained free throughout their entire ontogeny, alternating with the scale-like leaves inserted below them on the same branch; in some cases, these leaves also became fleshy. Conclusions Based on the ontogeny and arrangement of the two fleshy aril lobes in the teratological seed cones of Pseudotaxus, we suggest that the typical aril of Taxaceae could be readily interpreted as a fused pair of strongly swollen leaves rather than a modified integument. Our investigations of the cup-like aril of Pseudotaxus demonstrate a similarity not only with other Taxaceae but also with relatively distantly related conifers such as Phyllocladus (Podocarpaceae). [ABSTRACT FROM AUTHOR]

Background and Aims Intraspecific trait variation (ITV) is an important dimension of plant ecological diversity, particularly in agroecosystems, where phenotypic ITV (within crop genotypes) is an important correlate of key agroecosystem processes including yield. There are few studies that have evaluated whether plants of the same genotype vary along well-defined axes of biological variation, such as the leaf economics spectrum (LES). There is even less information disentangling environmental and ontogenetic determinants of crop ITV along an intraspecific LES, and whether or not a plant's position along an intraspecific LES is correlated with reproductive output. Methods We sought to capture the extent of phenotypic ITV within a single cultivar of soy (Glycine max) – the world's most commonly cultivated legume – using a data set of nine leaf traits measured on 402 leaves, sampled from 134 plants in both agroforestry and monoculture management systems, across three distinct whole-plant ontogenetic stages (while holding leaf age and canopy position stable). Key Results Leaf traits covaried strongly along an intraspecific LES, in patterns that were largely statistically indistinguishable from the 'universal LES' observed across non-domesticated plants. Whole-plant ontogenetic stage explained the highest proportion of phenotypic ITV in LES traits, with plants progressively expressing more 'resource-conservative' LES syndromes throughout development. Within ontogenetic stages, leaf traits differed systematically across management systems, with plants growing in monoculture expressing more 'resource-conservative' trait syndromes: trends largely owing to an approximately ≥50% increases in leaf mass per area (LMA) in high-light monoculture vs. shaded agroforestry systems. Certain traits, particularly LMA, leaf area and maximum photosynthetic rates, correlated closely with plant-level reproductive output. Conclusions Phenotypic ITV in soy is governed by constraints in trait trade-offs along an intraspecific LES, which in turn (1) underpins plant responses to managed environmental gradients, and (2) reflects shifts in plant functional biology and resource allocation that occur throughout whole-plant ontogeny. [ABSTRACT FROM AUTHOR]

Understanding developmental processes is foundational to clarifying the mechanisms by which convergent evolution occurs. Here, we show how a key convergently evolving trait is slowly 'acquired' in growing turtles. Many functionally relevant traits emerge late in turtle ontogeny, owing to design constraints imposed by the shell. We investigated this trend by examining derived patterns of shell formation associated with the multiple (at least 8) origins of shell kinesis in small-bodied turtles. Using box turtles as a model, we demonstrate that the flexible hinge joint required for shell kinesis differentiates gradually and via extensive repatterning of shell tissue. Disproportionate changes in shell shape and size substantiate that this transformation is a delayed ontogenetic response (3-5 years post-hatching) to structural alterations that arise in embryogenesis. These findings exemplify that the translation of genotype to phenotype may reach far beyond embryonic life stages. Thus, the temporal scope for developmental origins of adaptive morphological change might be broader than generally understood. We propose that delayed trait differentiation via tissue repatterning might facilitate phenotypic diversification and innovation that otherwise would not arise due to developmental constraints. [ABSTRACT FROM AUTHOR]

The family Cactaceae exhibits an assortment of fleshy and dry fruit types with various shapes dictated by the gynoecium outline and surrounding pericarpel. Consequently, conflicting terminology exists regarding cactus fruit classification because the fruit is a complex structure in which various floral parts participate in development. We examined fruit morphogenesis in four epiphytic cacti and provided a description of developmental events from post-anthesis to fruit maturation, which unveiled new structures valuable in fruit characterisation and taxonomy of the Hylocereeae and Rhipsalideae. Succinctly, the cactus fruit is a carpellar ovary embedded in a long-shoot (pericarpel). The pericarp originates from five components: internal ovarian epidermis that delimits the fruit locule, ovary (proper), collateral vascular bundles, pericarpel (receptacular origin), and external pericarpel epidermis. In addition, cell expansion and stored mucilage, a sticky substance involved in seed dispersal, occurs during fruit development. We propose the term cactidium, a complex fruit with accessory structures of pericarpellar origin surrounding the gynoecial boundary, to describe the cactus fruit. This term is appropriate because members of the Cactaceae bear unique traits, such as areoles in the reproductive structures (pericarpel), which may produce scale-leaves, bristles, and spines. [ABSTRACT FROM AUTHOR]

Article presents the results of research on the effect of chronic γ-irradiation in small doses on A. thaliana seedlings and seeds growth and development. Exposure rate for the seeds was 0,45 mGy/h (total absorbed dose 30 cSv) and 0,18 mGy/h for seedlings (total absorbed dose 3 cSv). Statistically significant differences in the ger-mination capacity, in the time of primary leaf rosette formation, in the hypocotyl length were revealed between irradiated and control seedlings. Plants from irradiated seeds differed by the higher growth rate of stem, they flowered and fruited earlier, but they also characterized on average shorter vegetative cycle in comparison with control plants. In our experiments it is shown еру significant impact of chronic low doses of γ-irradiation of seeds and seedlings on the ontogeny in A. thaliana and on the parameters that reflect the growth and development of the irradiated plants.

Abstract: Successive cambia in Vitaceae have been reported solely for Tetrastigma, a diverse genus of lianas found primarily in tropical Asia, extending into Australia. However, the structure and origin of these successive cambia have never been fully studied. Here we report the presence of this cambial variant in Tetrastigma retinervum and T. voinierianum, and describe its ontogeny in detail in the latter. New cambia appear successively in stems of Tetrastigma differentiating from the innermost parenchyma cells of the primary phloem, which are located interior to the pericyclic fiber strands. This study constitutes the first report of successive cambia being derived from primary phloem parenchyma in woody plants as a whole. Both species are members of Tetrastigma clade VI, the most species‐rich lineage within the genus. The examination of mature stems of additional species of Tetrastigma should determine the distribution of this unique type of cambial variant in the genus and enhance our understanding of the adaptive significance of this unusual character. [ABSTRACT FROM AUTHOR]

The article discusses the role of quantifying insect damage in identifying resistance mechanisms in plants. It mentions the information on the pest resistance screening. It also mentions the how the plant's ontogenetic stage affects the level of thrips resistance along with the impacts of thrips feeding on deformation of the leaves, short internodes, and chlorosis.

Ontogeny has been identified as a main source of variation in the expression of plant phenotypes. However, there is limited information on the mechanisms behind the evolution of ontogenetic trajectories in plant defense. We explored if risk of attack, herbivore damage, heritability, and phenotypic plasticity can promote or constrain the evolutionary potential of ontogenetic trajectories in three defensive traits. We exposed 20 genotypes of Turnera velutina to contrasting environments (shadehouse and field plots), and measured the cyanogenic potential, trichome density, and sugar content in extrafloral nectar in seedlings, juveniles and reproductive plants. We also assessed risk of attack through oviposition preferences, and quantified herbivore damage in the field. We estimated genetic variance, broad sense heritability, and evolvability of the defensive traits at each ontogenetic stage, and of the ontogenetic trajectories themselves. For plants growing in the shadehouse, we found genetic variation and broad sense heritability for cyanogenic potential in seedlings, and for trichome density at all ontogenetic stages. Genetic variation and heritability of ontogenetic trajectories was detected for trichome density only. These genetic pre-requisites for evolution, however, were not detected in the field, suggesting that environmental variation and phenotypic plastic responses mask any heritable variation. Finally, ontogenetic trajectories were found to be plastic, differing between shadehouse and field conditions for the same genetic families. Overall, we provide support for the idea that changes in herbivore pressure can be a mechanism behind the evolution of ontogenetic trajectories. This evolutionary potential, however, can be constrained by phenotypic plasticity expressed in heterogeneous environments. [ABSTRACT FROM AUTHOR]

Flourensia (Asteraceae, Heliantheae, Enceliinae) is an amphitropical genus of resinous subshrubs, shrubs and small trees with 13 North American and 20 South American species among which disagreement on the species limits of some members still exists. To resolve the taxonomy of the South American taxa, we carried out a combination of clustering (Ward's method with Gower distance coefficient) and ordination analyses (Principal Coordinate Analyses) based on 34 vegetative and reproductive characters scored from herbarium material, including types. Based on the results, we recognize 12 South American species: F. angustifolia, F. cajabambensis, F. fiebrigii, F. heterolepis, F. hirtissima, F. macrophylla, F. niederleinii; F. peruviana, F. polycephala, F. thurifera, F. tortuosa and F. suffrutescens. A number of species are placed in synonymy: Flourensia blakeana and F. hirta are synonymized under the name F. fiebrigii; Flourensia campestris, F. leptopoda, F. oolepis and F. riparia are synonymized under F. thurifera; Flourensia macroligulata is synonymized under F. tortuosa, and Flourensia polyclada is synonymized under F. suffrutescens. A taxonomic treatment of four redefined species as well as a key and distribution maps to all South American Flourensia species are provided. [ABSTRACT FROM AUTHOR]

Abstract: First‐year overwinter survival is a frequent bottleneck to the recruitment of Largemouth Bass Micropterus salmoides. Early ontogeny to piscivory provides increased overwinter survival through increased growth and the accumulation of lipids. This ontogeny is thought to be slowed by dense and complex vegetative habitats, but this hypothesis has not been directly tested. To address this question, we conducted enclosure experiments for 5 weeks during the typical time that juvenile Largemouth Bass would transition to piscivory (i.e., midsummer). Thirty‐two enclosures were constructed across two 0.10‐ha ponds and given one of four stem densities of simulated vegetation (0, 50, 250, and 500 stems/m2). Three juvenile Largemouth Bass and 30 juvenile Bluegills Lepomis macrochirus were added to each enclosure. All fish were sampled twice per week. Largemouth Bass growth was measured on all sample dates, and stomach samples were collected to determine diets on one date each week. Bluegill sizes and densities were manipulated to maintain the number of fish at 30 fish that were 25–35% of Largemouth Bass TL after each sampling event. Largemouth Bass stomach contents (percent by weight) were initially dominated by insects, and the bass transitioned to mostly fish prey by the end of the experiment. The use of fish prey, as measured by the presence of surviving Bluegills in the enclosures, significantly increased at the beginning of the second week at all stem densities, but fewer fish prey were eaten by bass in the 250‐stems/m2 treatment than in all other treatments throughout the experiment. Largemouth Bass also grew less in the 250‐stems/m2 treatment. We concluded that vegetation density does affect the foraging rate of piscivorous juvenile Largemouth Bass, but not necessarily the timing of the ontogeny to piscivory. However, differing results between this experiment and other previously published studies suggests vegetation may have an interactive effect with available prey types. [ABSTRACT FROM AUTHOR]

Most representatives of the third largest angiosperm family, Leguminosae, share monosymmetric flowers with a precisely defined number and morphology of all parts especially the corolla. However, in some lineages monosymmetry is lost. This alteration is usually associated with an increase of variation in number of floral organs. This paper reports the results of a survey on floral ontogeny in African basal papilionoid legume Cordyla pinnata . The flowers of this tree are polysymmetric (except for the carpel, if single), having a completely closed calyx which typically initiates as three lobes, no corolla, a polymerous androecium, and a gynoecium which is sporadically multicarpellate. Cordyla exhibits some similarity of floral traits with swartzioid legumes ( Swartzia p.p., Bocoa ) rather than with its nearest phylogenetic surrounding. Some features of convergence between Cordyla and mimosoid legumes are also remarkable, such as a showy polymerous androecium and anther glands. This species is an example of an evolutionary trend towards destabilization of the flower structure. Supernumerary carpels seemingly lack any adaptive value and represent a kind of ontogenetic overexpression. [ABSTRACT FROM AUTHOR]

Resource sharing is universal among connected ramets of clonal plants and is driven both by the developmental status of the ramets and the resource gradients. Above-ground competition forms spatial light gradients, but the role of resource sharing in such competition is unclear. We examined translocation of resources between mother and daughter ramets of Agrostis stolonifera under light heterogeneity throughout ramet ontogeny. We labelled ramets with 13C and 15N to estimate the bidirectional translocation of resources at three developmental stages of the daughters. In addition, we compared the final biomass of integrated and severed ramets in order to estimate the effect of integration on growth. Young developing daughters were supported by carbon, whereas nitrogen was only translocated towards daughters at the beginning of rooting, regardless of the light conditions. Shading of mothers was a major determinant of resource translocation between developed ramets, with carbon being preferentially moved to daughters from shaded mothers while nitrogen translocation was limited from daughters to shaded mothers. Surprisingly, the absolute amounts of translocated resources did not decline during development. Growth of daughters was enhanced by integration regardless of the shading. Overall, A. stolonifera maximizes the resource translocation pattern in order to enable it to spread from unfavourable habitats, rather than compensating for light heterogeneity among ramets. [ABSTRACT FROM AUTHOR]

The cuticular wax layer covers the aerial surface of plants and acts as a barrier between plants and the environment. The cuticle plays a key role in the protection of plants from pathogens, UV light, and transpiration. Variation in the wax quality and quantity is influenced by factors like the solvent used for extraction, species, ontogeny, and season. Compounds isolated from the cuticle layer have been studied by various methods and were found to play an important role from the ecological and physiological points of view. These compounds include esters, alcohols, ether, alkane, and aldehydes. Nonpolar compounds help reduce water loss in plants. The wax can be explored for its potential applications in developing sustainable green packaging material. This review article will facilitate biologists and nonbiologists to get comprehensive and updated knowledge about various aspects of cuticular wax including its chemical composition and variations among different species and seasons. Further studies of the wax composition will pave the way for classification of plant species and an understanding of plant protection from biotic and abiotic stresses. [ABSTRACT FROM AUTHOR]

Plants of buckwheat Fagopyrum esculentum possessing diploid and tetraploid genotypes were studied at the initial ontogenetic stages. They were compared in their morphophysiological characteristics, accumulation of phenolic compounds (including their main classes—phenylpropanoids and flavonoids), and activity of L-phenylalanine ammonia-lyase. An apparent resemblance in morphophysiological characteristics of seedlings was found between the two specimens, but diploid plants tended to faster linear growth than tetraploid ones. Differences in the accumulation of phenolic compounds in the hypocotyl and cotyledonous leaves were revealed. In most cases, in the course of seedling growth, the changes in phenylalanine ammonialyase activity did not correlate with the changes in the levels of these secondary metabolites. The effects of gene dosage were established towards accumulation of phenylpropanoids and anthocyanins in hypocotyls of seedlings and flavonoid accumulation in cotyledonous leaves. It is concluded that buckwheat seedlings with a tetraploid genotype have higher capacity than diploid seedlings for biosynthesis of phenolics. [ABSTRACT FROM AUTHOR]

We describe Sinoperonia gen. nov. for freshwater diatoms from mountainous regions of south-central China and northern Vietnam, whose single species, S. polyraphiamorpha sp. nov., develops monoraphid, biraphid and araphid frustules in the general proportions of 4:2:1 (China) or 2:1:1 (Vietnam), respectively, in different populations. Light and scanning electron microscope observations of this species show that raphe-bearing valves also have rimoportulae, and thus it is assigned to the Eunotiales. The raphe-bearing valves have the raphe at or near the middle of the valves, suggesting a placement in the Peroniaceae, and this new diatom is compared with the two other genera, Peronia and Actinellopsis, in this small but phylogenetically important group. We discuss the extreme morphological variation in this new taxon, and the growing body of evidence that the freshwater diatom flora of Southeast Asia may harbour many endemic genera as well as species. [ABSTRACT FROM AUTHOR]

Abstract: Senescence is the final stage of plant ontogeny before death. Senescence may occur naturally because of age or may be induced by various endogenous and exogenous factors. Despite its destructive character, senescence is a precisely controlled process that follows a well‐defined order. It is often inseparable from programmed cell death (PCD), and a correlation between these processes has been confirmed during the senescence of leaves and petals. Despite suggestions that senescence and PCD are two separate processes, with PCD occurring after senescence, cell death responsible for senescence is accompanied by numerous changes at the cytological, physiological and molecular levels, similar to other types of PCD. Independent of the plant organ analysed, these changes are focused on initiating the processes of cellular structural degradation via fluctuations in phytohormone levels and the activation of specific genes. Cellular structural degradation is genetically programmed and dependent on autophagy. Phytohormones/plant regulators are heavily involved in regulating the senescence of plant organs and can either promote [ethylene, abscisic acid (ABA), jasmonic acid (JA), and polyamines (PAs)] or inhibit [cytokinins (CKs)] this process. Auxins and carbohydrates have been assigned a dual role in the regulation of senescence, and can both inhibit and stimulate the senescence process. In this review, we introduce the basic pathways that regulate senescence in plants and identify mechanisms involved in controlling senescence in ephemeral plant organs. Moreover, we demonstrate a universal nature of this process in different plant organs; despite this process occurring in organs that have completely different functions, it is very similar. Progress in this area is providing opportunities to revisit how, when and which way senescence is coordinated or decoupled by plant regulators in different organs and will provide a powerful tool for plant physiology research. [ABSTRACT FROM AUTHOR]

Shading highbush blueberry plants generally leads to a delayed fruit development. Experiments have been performed to study the effects of light on fruit growth independently from the rest of the canopy. Clusters were shaded during different fruit growth periods. The equatorial diameter of the fruits as a function of days after full bloom followed a double-sigmoidal growth pattern, being fitted using a Gompertz II nonlinear mixed model, and absolute growth rates were obtained from each fitted model. Both whole-cycle shaded and second-stage shaded fruits showed a delayed peak in absolute growth curves with respect to both first-stage shaded and whole-cycle unshaded controls. Our results suggest that deficiency of light during the last stage of highbush blueberry fruits may lead to a substantial delay (of about 10–16 days) in harvest as compared with well-illuminated fruits. In order to estimate the contribution of intrinsic fruit photosynthesis to its own growth at different stages, clusters were subjected to girdling on their peduncles at different times. Girdling just before the second-stage resulted in fruits gaining between 35 and 40% of dry weight in comparison with the controls. This suggests that fruit photosynthesis may play a relevant role in fruit growth during the second sigmoidal stage, which in turn may contribute to explain the delayed growth observed in shaded fruits. [ABSTRACT FROM AUTHOR]

By a detailed ontogenetic study of Polemonium caeruleum pollen, tracing each stage of development at high TEM resolution, we aim to understand the establishment of the pollen wall and to unravel the mechanisms underlying sporoderm development. The main steps of exine ontogeny in Polemonium caeruleum, observed in the microspore periplasmic space, are spherical units, gradually transforming into columns, then to rod-like units (procolumellae), the appearance of the initial tectum, growth of columellae in height and tectum in thickness and initial sporopollenin accumulation on them, the appearance of the endexine lamellae and of dark-contrasted particles on the tectum, the appearance of a sponge-like layer and of the intine in aperture sites, the appearance of the foot layer on the base of the sponge-like layer and of spinules on the tectum, and massive sporopollenin accumulation. This sequence of developmental events fits well to the sequence of self-assembling micellar mesophases. This gives (together with earlier findings and experimental exine simulations) strong evidence that genome and self-assembly probably share control of exine formation. It is highly probable that self-assembly is an intrinsic instrument of evolution. [ABSTRACT FROM AUTHOR]

Not all plant traits from all regions have been standardized or databased. Some ecosystems, such as tropical grasslands, are under-represented in such databases owing to the difficulty in assessing bud banks and evaluating clonal growth. This study aimed to (i) determine whether Brazilian morphological traits of belowground organs can be translated into categories used in the CLO-PLA database and (ii) assess the applicability of clonal and bud bank traits standardized in the CLO-PLA database for Brazilian Aldama species, which have specialized belowground organs and are able to resprout. In all, 165 species, including herbs, subshrubs and shrubs, of 37 genera from different Brazilian ecosystems, were evaluated. Not all the traditional Brazilian morphological categories could be translated into CLO-PLA traits, resulting in a lower number of categories and loss of information regarding plant morphology. Furthermore, clonal and bud bank traits could be only partially evaluated for Aldama, since some traits showed seasonal variation. The CLO-PLA classification focused on the organs in relation to the soil surface, the connection between mother and daughter shoots, and the origin of buds from which daughter shoots sprout. In the Brazilian classification, by contrast, anatomical features or early ontogeny of the organ are very important. Nevertheless, our results might form the basis for future comparative studies across ecosystems and biomes, for which common trait standardization is necessary. However, further research is needed to assess the functional morphology of clonal and bud bank traits in tropical regions. [ABSTRACT FROM AUTHOR]

For practical reasons, all ramets of a clonal plant are considered to be independent individuals in demographical studies, but there are reports that ramet ontogeny is affected by their position in a clone. This means that ramets growing from buds located in certain parts of the rhizome system differ in size and probability of flowering from ramets emerging from buds at various positions. We studied the growth characteristics and ontogeny of tillers (ramets) of a rhizomatous grass in relation to their position in a clone and examined whether it is affected by the disturbance regime. We assessed the position of tillers in a clone, the developmental stage of their apical meristem and growth characteristics in mown and unmown stands of the rhizomatous grass Phalaris arundinacea at two sites, one representing optimal (lowland) and the other suboptimal (highland) environmental conditions. We found that tiller characteristics and the probability of a tiller to start flowering are related to the tiller position in a clone. Tiller differences were preserved even in suboptimal environmental conditions but disappeared after mowing, which equalized size and ontogeny. Our results imply that ramets of clonal plants are not independent demographical units, thus their position in a clone should be taken into account. [ABSTRACT FROM AUTHOR]

The production of shoots from roots (adventitious bud and shoot formation, root sprouting) first attracted attention in the 19th century as a morphological rarity. At that time, the first checklists of plants capable of root sprouting were compiled. Since then, experiments have proven that the ability to produce buds on roots serves the purpose of bud bank formation or represents a mode of clonal growth. The former enables resprouting after injury whereas the latter facilitates foraging for nutrients and vegetative multiplication. However, only a small proportion of root-sprouters have been studied so far, and for most of them we lack detailed data on the anatomy, morphology, ecology and physiology of adventitious shoot formation. These knowledge gaps hinder further understanding of their ecology and evolution. To support researchers interested in adventitious bud and shoot formation in any field of plant science, we compiled a list of plants considered capable of root sprouting based on the literature and the CLO-PLA database for the flora of the Czech Republic. Here we provide basic comparisons concerning the distribution of root sprouting ability among life history types, plants differing in rarity and invasive status, and taxonomic groups. Altogether 342 plant species are reported to be root-sprouters, i.e. 10% of the Czech flora. Root-sprouters are most commonly found among woody plants, less so among non-clonal perennial herbs, biennials and clonal herbs, and least commonly among annuals. Root-sprouters are more common among alien plants (especially woody ones) than among red-listed plants. Root sprouting usually plays a supplementary (facultative) or regenerative role in the plant life cycle. Root-sprouters occur in 64 families, mostly of dicots. The greatest number of root-sprouters belong to the Asteraceae and Rosaceae families (41). We have only rudimentary information on 145 species out of the 342 (42%) species that are regarded as root-sprouters. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Observations of floral ontogeny indicated that floral organ initiation in pentapetalous flowers most commonly results in a median-abaxial (MAB) petal during early development, a median-adaxial (MAD) petal being less common. Such different patterns of floral organ initiation might be linked with different morphologies of floral zygomorphy that have evolved in Asteridae. Here, we provide the first study of zygomorphy in pentapetalous angiosperms placed in a phylogenetic framework, the goal being to find if the different patterns of floral organ initiation are connected with particular patterns of zygomorphy. METHODS: We analyzed patterns of floral organ initiation and displays of zygomorphy, extracted from floral diagrams representing 405 taxa in 330 genera, covering 83% of orders (30 out of 36) and 37% of families (116 out of 313) in core eudicots in the context of a phylogeny using ancestral state reconstructions. KEY RESULTS: The MAB petal initiation is the ancestral state of the pattern of floral organ initiation in pentapetalous angiosperms. Taxa with MAD petal initiation represent ∼30 independent origins from the ancestral MAB initiation. There are distinct developmental processes that give rise to zygomorphy in different lineages of pentapetalous angiosperms, closely related lineages being likely to share similar developmental processes. CONCLUSIONS: We have demonstrated that development indeed constrains the processes that give rise to floral zygomorphy, while phylogenetic distance allows relaxation of these constraints, which provides novel insights on the role that development plays in the evolution of floral zygomorphy. [ABSTRACT FROM AUTHOR]

Premise of research. The flower of Leandra melastomoides (Melastomataceae) exhibits a singular condition that is the presence of two distinct and opposite portions in the sepals forming what is known as a double calyx. These portions may correspond to individual sepals, explaining the recognition of two calyx whorls. No studies resolving this structure are available in the literature. Thus, we aimed to elucidate the nature of the double calyx of L. melastomoides by analyzing its ontogeny. This approach allowed us to test hypotheses about how this structure developed. Methodology. Flowers and buds were preserved and prepared for observation in LM and SEM. Pivotal results. The sepals originate in the margin of the floral apex as six spherical primordia in a single outer whorl. The growth is unidirectional until a basal protuberance arises on the ventral surface of each primordium, which allows us to distinguish an upper and a lower part of this structure. The upper portion later takes on a dorsal position. The lower portion shows laminar growth, various vascular traces, and nonglandular emergences. The dorsal portion becomes conical, is lined with nonglandular emergences, and is supplied by a single vascular trace. The vascularization of each part of a sepal has a common origin from the radial divergence of the same trace that emerges from the vascular ring of the hypanthium. Conclusions. The calyx of L. melastomoides actually consists of only one whorl, because both dorsal and laminar parts of a sepal originate from a single primordiumin a peripheral region of the floral meristem. The dorsal projection is similar to that described in the literature under the term Vorläuferspitze. The understanding of the existence of two distinct ontogenetic modules for the same organ allows us to compare it with other organs and taxonomic groups and to search for a better descriptive terminology for the structure in this group. [ABSTRACT FROM AUTHOR]

We examined the morphology of the cauline domatia of the semi-myrmecophyte Humboldtia brunonis at different stages of ontogeny. We observed that the hollow chamber in H. brunonis is spontaneously formed by the plant, and suggest this to be a collective effect of both schizogeny and lysogeny, following acropetal lignification of the pith cells as the domatium internode swells up. Unlike some other cauline domatia, there is a self-opening slit that provides access to the domatium chamber. We investigated the micro-structure of the inner wall of the domatia using scanning electron microscopy, and observed that cells that form the inner lining of the domatia cavity have canaliculated, lignified sclerenchyma with numerous plasmodesmata, as reported for the true myrmecophyte Leonardoxa africana , which could explain the observed nutrient flux from domatia-dwelling invertebrates into the host plant. We also observed fungal mycelia in ant-occupied domatia, though the role of fungi in this ant–plant system awaits further investigation. [ABSTRACT FROM AUTHOR]

Background and Aims The functional relevance of heteroblasty, an abrupt morphological change in the ontogeny of a considerable number of angiosperm species, is still largely unresolved. During the ontogeny of many epiphytic Tillandsioids (Bromeliaceae), such a change occurs when small individuals transform into larger, tank-forming individuals that are capable of external water storage. Apart from its fundamental effect on plant water relations, the associated transition from narrow to broader leaves also affects plant architecture. The morphological changes and their effect on light interception may be especially relevant for heteroblastic species in the moist understorey, which are expected to be limited primarily by light. Methods A functional structural plant model (Yplant) was used to construct digital replicas of atmospheric and tank-forming individuals of four species, two of them naturally growing in exposed conditions and two occurring in understorey sites. This allowed the determination of leaf display efficiencies as well as a systematic analysis of leaf architectural traits and their effect on light interception. Key Results Modifying existing plant morphologies showed that broader leaves cause more self-shading within the plant. This supports the hypothesis that species from the light-limited understorey benefit from the early atmospheric life form through increased light capture. Modelling plant morphology that continuously followed the ontogenetic trajectories of the leaf architectural traits revealed that the rising total leaf number in atmospheric individuals constantly increased self-shading. Therefore, at a certain ontogenetic stage, a tipping point was reached when the tank form was even favourable in terms of light capture as it was associated with fewer leaves. Conclusions The effects of changes in leaf morphology and leaf architecture on plant light capture may explain the common occurrence of heteroblastic species in the understorey of Neotropical forests, which does not negate a simultaneous positive effect of heteroblasty on plant water relations. [ABSTRACT FROM AUTHOR]

Plant-herbivore interactions can be mediated by plant apparency, defensive and nutritional quality traits that change through plant ontogeny, resulting in age-specific herbivory. In dioecious species, opposing allocation patterns in defense may lead to sex-biased herbivory. Here, we examine how onto stage and plant sex determine levels of herbivore damage in understory herb Mercurialis perennis under field conditions. We analyzed variation in plant size (height, total leaf area), physical (specific leaf area) and chemical (total phenolic and condensed tannins contents) defense, and nutritional quality (total water, soluble protein and nonstructural carbohydrate contents) during the shift from reproductive to post-reproductive stage. Furthermore, we explored correlations between the analyzed traits and levels of foliar damage. Post-reproductive plants had lower levels of chemical defense, and larger leaf area removed, in spite of having lower nutritive quality. Opposing patterns of intersexual differences were detected in protein and phenolic contents during reproductive stage, while in post-reproductive stage total leaf area was sexually dimorphic. Female-biased herbivory was apparent only after reproduction. Plant size parameters combined with condensed tannins content determined levels of foliar damage during post-reproductive stage, while the only trait covarying with herbivory in reproductive stage was total nonstructural carbohydrate content. Our results support claims of optimal defense theory – sensitive stage of reproduction was better defended. We conclude that different combinations of plant traits mediated interactions with herbivores in mature stages. Differences in reproductive allocation between the sexes may not immediately translate into different levels of damage, stressing the need for considering different ontogenetic stages when exploring sex bias in herbivory. [ABSTRACT FROM AUTHOR]

Previous works show the development of thicker leaves on tolerant plants growing under cadmium (Cd) contamination. The aim of this study was to evaluate the Cd effects on the leaf meristems of the tolerant species Schinus molle. Plants were grown in nutrient solution containing 0, 10, and 50 μM of Cd. Anatomical analysis was performed on leaf primordia sampled at regular time intervals. Under the lowest Cd level (10 μM), increased ground meristem thickness, diameter of the cells, cell elongation rate, and leaf dry mass were found. However, 50 μM of Cd reduced all these variables. In addition, the ground meristem cells became larger when exposed to any Cd level. The epidermis, palisade parenchyma, and vascular tissues developed earlier in Cd-exposed leaves. The modifications found on the ground meristem may be related to the development of thicker leaves on S. molle plants exposed to low Cd levels. Furthermore, older leaves showed higher Cd content when compared to the younger ones, preventing the Cd toxicity to these leaves. Thus, low Cd concentrations change the ground meristem structure and function reflecting on the development of thicker and enhanced leaves. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the ontogenesis and structural and morphological features of various life forms of Nepeta pulchella Pojark. (Lamiaceae). The environmental and coenotic features of the species habitats within the Aksu-Zhabagly State Nature Reserve have been described. It is found that N. pulchella inhabits areas from the middle part of the mountains to the subalpine belt. The status of coenopopulations in two types of plant communities has been examined. Depending on various ecological and coenotic conditions, N. pulchella individuals develop two life forms: taprooted caudex and short-rhizomatous-taprooted ones. Individuals belonging to these biomorphs go through complete sophisticated ontogenesis. The following morphogenetic phases have been described for the first biomorph: primary shoot → main axis → primary bush → clone; for the second one: primary shoot → main axis → primary bush → tillering particle → nontillering particle. The studied coenopopulations were normal, transitional to mature, resistant, and incomplete. The ecocoenotic and structural-morphological analyses made it possible to identify in the N. pulchella morphogenesis a number of features determined by phylogenetic ties with closely related taxa. [ABSTRACT FROM AUTHOR]

Dicranophyllum gallicum Grand'Eury is described by means of a morphometric analysis of eighty two samples from various old and new localities in western and central Europe. Stem, leaf cushions, leaf scars, leaves, axillary structures and potential seeds are described in detail, and discussed in comparison to earlier studies. The encountered variability in size and structure is shown to be higher than what was described earlier. The organisation of the leaf cushion and scar density vary gradually with the stem width, while stratigraphic position and ecology do not relate to it. It is concluded that the described variability represents an ontogenetic feature rather than a phylogenetic or ecologic one. The juvenile plants are characterised by small stems, a high leaf scar density and elongated leaf cushions with a dominant apical field, while mature specimens are characterized by a wide stem, a relatively low leaf scar density and relatively wide leaf cushions with a pronounced basal field. Axillary shoots and potential seeds of D. gallicum are described and illustrated in detail for the first time. A reconstruction based on the studied material is presented. [ABSTRACT FROM AUTHOR]

A single plant can interact both positively and negatively with its neighbors through the processes of facilitation and competition, respectively. Much of the variation in the balance of facilitation and competition that individuals experience can be explained by the degree of physical stress and the sizes or ages of plants during the interaction. Germination phenology partly controls both of these factors, but its role in defining the facilitation-competition balance has not been explicitly considered. I performed an experiment in a population of the winter annual Arabidopsis thaliana (Brassicaceae) to test whether germinating during physically stressful periods leads to facilitation while germinating during periods that promote growth and reproduction leads to competition. I manipulated germination and neighbor presence across two years in order to quantify the effects of the local plant community on survival, fecundity, and total fitness as a function of germination phenology. Neighbors increased survival when germination occurred under conditions that were unsuitable for survival, but they reduced fecundity in germinants that were otherwise the most fecund. Later germination was associated with facilitation in the first year but competition in the second year. These episodes of facilitation and competition opposed each other, leading to no net effect of neighbors when averaged over all cohorts. These results indicate that variation in germination timing can explain some of the variation in the facilitation-competition balance in plant communities. [ABSTRACT FROM AUTHOR]

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This study examined changes in sweet cherry buds of ‘Summit’ cultivar in four seasons (2011/12–2014/15) with respect to the nitrogen (N) content and the profile of eight free amino acids (asparagine (Asn), aspartic acid (Asp), isoleucine (Ile), glutamine (Gln), glutamic acid (Glu), arginine (Arg), alanine (Ala), histidine (His)). The presented results are to our knowledge the first under natural conditions in fruit tree orchards with a high temporal resolution from the dormant stage until cluster development. The N content in the buds from October, during endo- and ecodormancy until the beginning of ontogenetic development was a relatively stable parameter in each of the four seasons. The N accumulation into the buds began after ‘swollen bud’ and significant differences were visible at ‘green tip’ with an N content of 3.24, 3.12, 3.08, 2.40 which increased markedly to the mean of ‘tight’ and ‘open cluster’ by 3.77%, 3.78%, 3.44% and 3.10% in 2012–2015, respectively. In the buds, levels of asparagine were higher (up to 44 mg g −1 DW −1 ) than aspartic acid (up to 2 mg g −1 DW −1 ) and aspartic acid higher than isoleucine (up to 0.83 mg g −1 DW −1 ). Levels of glutamine were higher (up to 25 mg g −1 DW −1 ) than glutamic acid (up to 20 mg g −1 DW −1 ). The course of the arginine content was higher in 2011/12 compared to 2012/13, 2013/14 and 2014/15 which showed only slight differences. The alanine content in the buds was denoted in the four seasons only by relatively minor changes. The histidine content was higher in 2011/12 and 2012/13 compared to 2013/14 and 2014/15 which showed a comparable pattern. For 6 amino acids (Asn, Asp, Ile, Glu, Arg, Ala), the highest content was observed in 2012/13, the warmest period between swollen bud and open cluster. However in 2014/15, the season with the lowest mean temperature of 8.8 °C, only the content of Gln was the lowest. It was not possible to explain any seasonal differences in the amino acid content by environmental factors (air temperature) on the basis of few seasons. From none of the measured free amino acids could a clear determination of the date of endodormancy release (t 1 ) or the beginning of the ontogenetic development (t 1 * ) be derived. Therefore, these amino acids are no suitable markers to improve phenological models for the beginning of cherry blossom. [ABSTRACT FROM AUTHOR]

We use the molecular data available for the plant genera currently distributed in the Canaries to propose a hypothetical framework that updates the Surfing Syngameon Hypothesis (SSH) to explain the origins of the high genetic diversity of this flora in connection with the General Dynamic Model of Island Ontogeny and the available knowledge on the geology of the islands. Based on our review, we propose that (i) secondary contact and subsequent gene flow among genotypes previously confined to the mainland or to other insular regions generated syngameons across the archipelago, whose temporal extent and distribution were influenced by the ontogenetic stages of each island; and (ii) the resulting high levels of genetic variation were critical to the successful colonization of many other regions in the Canaries, especially those where more complex geographical and ecological features promoted gene flow cessation, drift, and/or eventual selection processes leading to species radiations. Under the updated SSH, the colonizing contingents of the islands would not necessarily have low genetic variation, because multiple colonizations followed by secondary contact among different genotypes would enhance genetic diversity through introgressive hybridization. As with other theories, the SSH contends that the monophyly detected in a large proportion of its lineages is artifactual. However, the SSH further differs from past hypotheses in (i) suggesting a spatio-temporal sequence of events giving rise to syngameons in different islands and island regions, (ii) showing that the ontogenetic mismatch among the Canarian islands should be largely responsible for similar levels of population genetic diversity in many congeneric endemics distributed in several islands, (iii) hypothesizing a substantial role for both allopolyploid and homoploid hybridization in the origins of the Canarian flora, and (iv) positing that, in many cases, the admixture processes in the syngameons formed at different stages of the islands’ ontogeny made possible the rapid colonization of multiple environments, and the generation of the current floristic diversity. [ABSTRACT FROM AUTHOR]

The transition between ontogenetic stages, from juvenile to reproductive adult, is an important moment in the life history of individuals in a plant population, since the persistence of their genes depends on it. The size of an individual is recognized as a predictor for this transition, but little is known about what determines the minimum size to become a reproductive adult, or if a higher growth rate can anticipate or not that transition. In addition, the relationship between size and ontogeny have not yet been studied for woody species. To verify whether the change in ontogenetic stage in woody plants is dependent on plant size, we followed the development of even-aged cultivated seedlings of 53 native species of the Brazilian savanna, Assis State Forest, State of São Paulo, up to their first reproductive event. In 83% of the species the tallest individual - the fastest growing in height - was the first to bloom. Our results support previous studies that consider plant size as one of the most important factors driving certain demographic processes, and allow inferences about the importance of size and growth rate on plant fitness and community assembly. Individuals with higher growth rates during the juvenile stage are the first to reach maturity. Consequently, among individuals of the same cohort, those growing faster will take ecological and evolutionary advantage since they can reproduce precociously and leave descendants prior to their smaller conspecifics, increasing the expression of their genes in the community. It is therefore expected that, along the evolutionary scale, growth rate of Brazilian savanna woody species should continuously increase. [ABSTRACT FROM AUTHOR]

One of central goal in ecology is to understand how plants respond to environment and what kind of attributes that can be obtained with an easy way to interpret the complexity of nature, especially on vegetation response. Ecologists use functional traits to understand how plants respond to environmental changes. Plant species may have experienced different environmental conditions during their ontogeny. Thus, they may show different patterns of ontogenetic trait variation (OTV) as their response to different environmental condition. In this study, the relationship between trait variation on different habitat and across ontogenetic stages both on community and population levels were investigated. Five selected leaves traits (leaf area, specific leaf area, leaf thickness, leaf dry matter content and leaf succulence) were examined to look at plant response along soil water content and light gap interception gradient in Kenting forest dynamics plot (KFDP), Southern Taiwan. Leaf area was the most varied trait across habitat and ontogeny. Leaf thickness reveals an opposite pattern compare to leaf area. Leaf dry matter content (LDMC) showed less variation either between or within species and across ontogeny. Shift of community responses on environmental gradient by trait through ontogeny showed that intraspecific variation is important to be considered in ecological study. The other important finding in this study was by only using mean species we can misleading in understanding of plant responses to the environmental gradient in order to their adaptation both across different habitat and ontogenetic stages. [ABSTRACT FROM AUTHOR]

Pronounced strategy shifts along ontogeny have been observed in several tree species, mainly because of the trend to maximize growth during the seedling stage, which constitutes the most vulnerable part of the tree's life cycle. Our aim here was to analyze the ontogenetic changes in crown characteristics and light capture patterns in three Quercus species: the evergreens Quercus ilex and Quercus suber and the deciduous Quercus faginea co-occurring in a Mediterranean open woodland. The seedlings were distributed in the large clearings among the adults and received full sunlight. We constructed three-dimensional models of the aerial parts of seedlings and mature trees of the three species, using the YplantQMC program. Large differences between growth stages were observed for all variables. The seedlings exhibited smaller branch sizes and crown densities than those observed in the adult trees. Leaf angles to horizontal also tended to increase during ontogeny, whereas leaf dispersion and the observed distances between leaves tended to decrease. The amount of photosynthetic radiation absorbed per unit leaf area throughout the growing season was lower in adult specimens than in young specimens. Changes in absorption efficiency during ontogeny were more intense for the species with longer leaf life span at maturity. We conclude that more intense ontogenetic shifts in species with longer leaf life span reflect the priority change from the maximization of short-term productivity at the seedling stage to maximizing leaf longevity during the adult stage. [ABSTRACT FROM AUTHOR]

Water plays an important role in augmenting the growth and development of crop plants in their different stages of ontogeny. Since water is the life line for accruing desired yield levels, its time of application and method of application plays an important role in increasing the yield levels besides saving water. Further, water is the prime natural resource, which is often costly and limiting input particularly in arid and semi arid regions, hence needs judicious use to reap the maximum benefit from this limiting resource. Off late, among irrigation methods, drip irrigation is receiving better appreciation, acceptance, adaption and plays an important role in saving the water in water scarce areas. It enables the efficient use of limited water with higher water use efficiency. Optimum irrigation levels with suitable method would help in enhancing the economic yield as well as water use efficiency in many field crops including sunflower crop in line with the high value commercial and horticultural crops. [ABSTRACT FROM AUTHOR]

In this study, effects of lead on ultracellular structure and pigment contents of Brassica napus were examined. Pb(II) was added in soluble form to soil prior to sowing. Pb contents were measured in plant organs at the ontogenetic stages of flowering (FL) and physiological maturity (PM). Pigment contents were evaluated through reflectance measurements. Pb content in organs was found to decrease in the order; roots>stems>leaves. Lead content in senescent leaves at FL stage was significantly higher than harvested leaves, strongly suggesting a detoxification mechanism. Leaves and stems harvested at the PM stage showed damage at subcellular level, namely chloroplast disorganization, cell wall damage and presence of osmiophilic bodies. Chlorophyll content increased in the presence of Pb at the FL stage, compared with control; at the PM stage, chlorophyll contents decreased with low Pb concentration but showed no significant differences with control at high Pb soil concentration. The results suggest an increase in antioxidants at low Pb concentration and cell damage at higher lead concentration. [ABSTRACT FROM AUTHOR]

Root-knot nematodes (RKNs; Meloidogyne spp.) induce feeding cells (giant cells; GCs) inside a pseudo-organ (gall) from still unknown root cells. Understanding GCs ontogeny is essential to the basic knowledge of RKN--plant interaction and to discover novel and effective control strategies. Hence, we report for the first time in a model plant, Arabidopsis, molecular, and cellular features concerning ectopic de novo organogenesis of RKNs GCs in leaves. RKNs induce GCs in leaves with irregular shape, a reticulated cytosol, and fragmented vacuoles as GCs from roots. Leaf cells around the nematode enter G2-M shown by ProCycB1;1:CycB1;1(NT)-GUS expression, consistent to multinucleated GCs. In addition, GCs nuclei present irregular and varied sizes. All these characteristics mentioned, being equivalent to GCs in root-galls. RKNs complete their life cycle forming a gall/callus-like structure in the leaf vascular tissues resembling auxin-induced callus with an auxin-response maxima, indicated by high expression of DR5::GUS that is dependent on leaf auxin-transport. Notably, induction of leaves calli/GCs requires molecular components from roots crucial for lateral roots (LRs), auxin-induced callus and root-gall formation, i.e., LBD16. Hence, LBD16 is a xylem pole pericycle specific and local marker in LR primordia unexpectedly induced locally in the vascular tissue of leaves after RKN infection. LBD16 is also fundamental for feeding site formation as RKNs could not stablish in 35S::LBD16-SRDX leaves, and likely it is also a conserved molecular hub between biotic and developmental signals in Arabidopsis either in roots or leaves. Moreover, RKNs induce the ectopic development of roots from leaf and root-galls, also formed in mutants compromised in LR formation, arf7/arf19, slr, and alf4. Therefore, nematodes must target molecular signatures to induce post- embryogenic de novo organogenesis through the LBD16 callus formation pathway partially different from those prevalent during normal LR development. [ABSTRACT FROM AUTHOR]

Domestication might affect plant size. We investigated whether herbaceous crops are larger than their wild progenitors, and the traits that influence size variation., We grew six crop plants and their wild progenitors under common garden conditions. We measured the aboveground biomass gain by individual plants during the vegetative stage. We then tested whether photosynthesis rate, biomass allocation to leaves, leaf size and specific leaf area ( SLA) accounted for variations in whole-plant photosynthesis, and ultimately in aboveground biomass., Despite variations among crops, domestication generally increased the aboveground biomass (average effect +1.38, Cohen's d effect size). Domesticated plants invested less in leaves and more in stems than their wild progenitors. Photosynthesis rates remained similar after domestication. Variations in whole-plant C gains could not be explained by changes in leaf photosynthesis. Leaves were larger after domestication, which provided the main contribution to increases in leaf area per plant and plant-level C gain, and ultimately to larger aboveground biomass., In general, cultivated plants have become larger since domestication. In our six crops, this occurred despite lower investment in leaves, comparable leaf-level photosynthesis and similar biomass costs of leaf area ( i.e. SLA) than their wild progenitors. Increased leaf size was the main driver of increases in aboveground size. Thus, we suggest that large seeds, which are also typical of crops, might produce individuals with larger organs ( i.e. leaves) via cascading effects throughout ontogeny. Larger leaves would then scale into larger whole plants, which might partly explain the increases in size that accompanied domestication. [ABSTRACT FROM AUTHOR]

The Iris flower is a complex morphological structure composed of two trimerous whorls of functionally distinct petaloid organs (the falls and the standards), one whorl of the stamens and one tricarpellary gynoecium. The petal-like style arms of the carpels are banded over the basal part of the falls, forming three pollination tunnels, each of which is perceived by the Iris pollinators as a single bilaterally symmetrical flower. Apart from the stamens, all petaloid floral organs are preferentially involved in advertising rewards to potential pollinators. Here we used the methods of geometric morphometrics to explore the shape variation in falls, standards and style arms of the Iris pumila flowers and to disentangle the symmetric and the asymmetric component of the total shape variance. Our results show that symmetric variation contributes mostly to the total shape variance in each of the three floral organs. Fluctuating asymmetry (FA) was the dominant component of the asymmetric shape variation in the falls and the standards, but appeared to be marginally significant in the style arms. The values of FA indexes for the shape of falls (insects' landing platforms) and for the shape of standards (long-distance reward signals) were found to be two orders of magnitude greater compared to that of the style arms. Directional asymmetry appeared to be very low, but highly statistically significant for all analyzed floral organs. Because floral symmetry can reliably indicate the presence of floral rewards, an almost perfect symmetry recorded for the style arm shape might be the outcome of pollinator preferences for symmetrical pollination units. [ABSTRACT FROM AUTHOR]

Magonia pubescens is a common native tree species of the Cerrado biome (neotropical savanna) with potential for biofuel production. We describe the ontogenesis of the oleaginous seed of this species and development of its wing and unusual mucilaginous layer. Ovaries and seeds were accompanied throughout their development using standard methods of plant anatomy; the cotyledons were examined using transmission electron microscopy. The wing consists of two juxtaposed layers formed by lateral expansion of the testa. The seed core is composed of three layers, with the outer layer being highly hygroscopic. A conspicuous raphe surrounds the embryo in the median longitudinal plane, and the nucellus is proliferative and secretory. The embryo is oleaginous and late-maturing. Seed development requires approximately 350 days and takes place in seven phases: (1) ovule fertilization; (2) raphe differentiation; (3) wing expansion; (4) differentiation of the seed coat layers; (5) embryo expansion; (6) maturation of the wing and the mucilaginous layer; and, (7) accumulation of mucilage in the core and oil in the embryo. The winged seeds of M. pubescens have complex structures and important adaptive features such as the mucilaginous core and raphe, which contribute to hydration during germination, as well as abundant oil reserves in the embryo that aid seedling establishment. These seeds structure contribute to the reproductive success of this species and its adaptation to the highly seasonal Cerrado biome. [ABSTRACT FROM AUTHOR]