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Tablegrape (Vitis vinifera L.) yield is lower in the subtropics than in Mediterranean production systems. To explain this difference, the development of inflorescence primordia of ?Menindee Seedless? grape in Emerald, Australia, one of the hottest grape-growing regions in Australia, was described using dissecting and scanning electron microscopy. Inflorescence initiation and branching occurred 42 and 70 days after budburst (Growth Stages 23 and 33 of a modified Eichhorn-Lorenz system, respectively). This period is 1?2 weeks earlier than under temperate conditions. From 70 to 268 days after budburst (leaf fall), only 44% of sample buds from nodes 4 to 6 of potential canes showed inflorescence primordia. It is concluded that the lower yield in the subtropics is due to low bud fertility, with disrupted inflorescence development associated to high summer temperatures.

In plant tissue culture, callus forms from detached explants in response to a high-auxin-to-low-cytokinin ratio on callus-inducing medium. Callus is a group of pluripotent cells because it can regenerate either roots or shoots in response to a low level of auxin on root-inducing medium or a high-cytokinin-to-low-auxin ratio on shoot-inducing medium, respectively1. However, our knowledge of the mechanism of pluripotency acquisition during callus formation is limited. On the basis of analyses at the single-cell level, we show that the tissue structure of Arabidopsis thaliana callus on callus-inducing medium is similar to that of the root primordium or root apical meristem, and the middle cell layer with quiescent centre-like transcriptional identity exhibits the ability to regenerate organs. In the middle cell layer, WUSCHEL-RELATED HOMEOBOX5 (WOX5) directly interacts with PLETHORA1 and 2 to promote TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS1 expression for endogenous auxin production. WOX5 also interacts with the B-type ARABIDOPSIS RESPONSE REGULATOR12 (ARR12) and represses A-type ARRs to break the negative feedback loop in cytokinin signalling. Overall, the promotion of auxin production and the enhancement of cytokinin sensitivity are both required for pluripotency acquisition in the middle cell layer of callus for organ regeneration.

Several structural attributes associated with the buds of shoot apices of angiosperms have been related to protection both at the mechanical and chemical defense levels. Although several characteristics related to the protection of shoot buds are known in different taxa of Sapindales, their occurrence in the neotropical genus Homalolepis (Simaroubaceae) are still unknown. Homalolepis includes 28 species mostly with extra-Amazonian distribution, occurring mainly in the Brazilian domains of the “Cerrado” and the Atlantic Forest. Its species vary widely in terms of habit, many of which are considered adaptations to the environments in which they occur. In this study, usual light and scanning electron microscopy techniques were applied in order to analyze the morphoanatomical and histochemical characteristics associated with the protection of apical and lateral shoot buds in phanerophyte (H. arenaria Devecchi & Pirani (Devecchi & Pirani), H. glabra (Engl.) Devecchi & Pirani and H. insignis (A.St.-Hil. & Tul.) Devecchi & Pirani) and geophyte (H. pumila Devecchi & Pirani, H. salubris (Engl.) Devecchi & Pirani and H. suffruticosa (Engl.) Devecchi & Pirani) species. Glandular prophylls, cataphylls, suberized layer on the leaf primordium, colleters, non-glandular trichomes, as well as a secretory canal with precocious development in the leaf primordium are among the characteristics that can be considered strategies for the protection of shoot buds in the studied species. Such structures are related to physical (cataphyll and suberized layer) and chemical (prophylls and secretory canal) protection or both (trichomes), against desiccation or attack by herbivores.

Secondary root emergence is a crucial trait that shapes the plant’s underground system. Virtually every developmental step of root primordium morphogenesis is controlled by auxin. However, how the hormone controls cell separation in primordium-overlaying tissues through wall loosening is poorly understood. Here, we took advantage of white lupin and its spectacular cluster root development to assess the contribution of auxin to this process. We show that auxin’s positive role on rootlet emergence is associated with an upregulation of cell wall pectin modifying and degrading genes. Downregulation of a pectinolytic enzyme gene expressed in cells surrounding the primordium resulted in delayed emergence. Pectins were demethylesterified in the emergence zone and auxin treatment further enhanced this effect. Additionally, we report specific rhamnogalacturonan-I modifications during cortical cell separation. In conclusion, we propose a model in which auxin has a dual role during rootlet emergence: Firstly, through active pectin demethylesterification and secondly by regulating the expression of cell wall remodeling enzymes.

The distribution of essential nutrients such as potassium (K), phosphorous (P), calcium (Ca), sulfur (S) and chlorine (Cl) within root tissues is crucial aspect of plant growth but nothing is known regarding this subject in seedlings of dicotyledons such as peanut (Arachis hypogaea). We used scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) and inductively coupled plasma optical emission spectrometry (ICP-OES) to analyze element distributions in developing root tissues. Distribution patterns and concentrations of endogenous K, P, S and exogenous Ca from seeds grown in water varied along the length of peanut radicle and were tissue specific. Semi-quantitative SEM/EDS data indicated 24 mM K in the cortex and 46 mM K in the stele at a distance of 5 mm from the root tip. The P concentration in the same region was 15 mM in cortex and 22 mM in stele. The concentration of K and P decreased in the more mature parts of the root. SEM–EDS element concentrations values were lower for K and higher for P when compared with the ICP-OES data of root segments. Peanut roots grown in 10 mM Ca(NO3)2 solution for hours showed tissue-specific Ca distribution at 25 mm from the root tip with the highest levels detected in portions of the cortex. The parent root cortex centrifugal to the tip of developing lateral root primordia had lower levels of calcium than could be detected by SEM/EDS.

Embryonic development of reproductive organs in rediae of the digenean Bunocotyle progenetica was studied using transmission electron microscopy. The germinal primordium becomes morphologically distinct in early embryos as a weakly separated cell mass with a forming cavity. It consists of undifferentiated, differentiating, and supporting cells. As embryos develop, the supporting cells form a wall around the enlarging cavity. Other cells of the germinal primordium are incorporated into the wall as solitary cells or as small cell aggregations. Those situated posteriorly give rise to an incipient germinal mass functioning during postembryonic development. Undifferentiated and differentiating cells in the middle and the anterior part of the primordium ensure a considerable growth of the cavity wall, which incorporates solitary germinal cells. In advanced embryonic rediae, these cells mature, cleave, and give rise to germinal balls, which enter the forming brood cavity. In the most mature embryonic rediae, all these early cercarial embryos reside in a brood cavity, which is lined by that time with a syncytium continuous with the supporting tissue of the incipient germinal mass. Based on our results and the literature data, we suggest that the morphogenesis of the reproductive apparatus of the daughter parthenitae in hemiuroid digeneans may be characterized by (1) emergence of an incipient brood cavity within the germinal primordium, (2) formation of the cavity lining from the cells of the germinal primordium, (3) fragmentation and uneven distribution of the germinal material of the germinal primordium around the cavity, and (4) an anticipatory development of some of this germinal material.

Bud endodormancy is accompanied by transport channel apertures blockage through callose deposition, and its resume to growth requires evoking β-1,3-glucanases (BGs) to unchoke the conduit. To understand out its working manner, the statuses of the transport channels were evaluated and candidate BGs were identified during chilling and gibberellin acids (GA) induced dormancy release in tree peony. Calcein reflects plasmodesmata permeability, and no calcein was observed in the bud together with density aniline blue fluorescent around the stem phloem at 0 d chilling. With the increase of chilling accumulation, the contents of glucan declined and the activities of gulcanase increased gradually in buds, and the calcein reached the top of flower primordia at 21 d chilled bud. Both GA3 and GA4 feedings promoted bud sprouting and growth along with rapidly unchoking the transport channels, and GA3 was more effective. Several candidate β-1,3-glucanase genes were detected, combining transcriptional profiling and quantitative PCR analysis. PsBG1, PsBG3, PsBG6, PsBG8 and PsBG9 were inducible by chilling accumulation and presented laminarin hydrolyzing activities after prokaryotically expression, while PsBG1, PsBG3, PsBG8 and PsBG9 responded to GAs application. Subcellular localizations revealed that PsBG6 and PsBG9 were plasmodesmata residents. It was concluded that PsBG6 played a vital role in chilling accumulation response and PsBG9 was central in GAs-induced dormancy release, and they could be used as marker genes for dormancy release in tree peony. These results were of great value to understand the mechanism of dormancy regulation and as an important fundamental for forcing culture technology in tree peony.

The shoot organ boundaries have important roles in plant growth and morphogenesis. It has been reported that a gene encoding a cysteine-rich secreted peptide of the EPIDERMAL PATTERNING FACTOR-LIKE (EPFL) family, EPFL2, is expressed in the boundary domain between the two cotyledon primordia of Arabidopsis thaliana embryo. However, its developmental functions remain unknown. This study aimed to analyze the role of EPFL2 during embryogenesis. We found that cotyledon growth was reduced in its loss-of-function mutants, and this phenotype was associated with the reduction of auxin response peaks at the tips of the primordia. The reduced cotyledon size of the mutant embryo recovered in germinating seedlings, indicating the presence of a factor that acted redundantly with EPFL2 to promote cotyledon growth in late embryogenesis. Our analysis suggests that the boundary domain between the cotyledon primordia acts as a signaling center that organizes auxin response peaks and promotes cotyledon growth.

Most legumes can establish a symbiotic association with soil rhizobia that trigger the development of root nodules. These nodules host the rhizobia and allow them to fix nitrogen efficiently. The perception of bacterial lipo-chitooligosaccharides (LCOs) in the epidermis initiates a signaling cascade that allows rhizobial intracellular infection in the root and de-differentiation and activation of cell division that gives rise to the nodule. Thus, nodule organogenesis and rhizobial infection need to be coupled in space and time for successful nodulation. The plant hormone cytokinin (CK) contributes to the coordination of this process, acting as an essential positive regulator of nodule organogenesis. However, the temporal regulation of tissue-specific CK signaling and biosynthesis in response to LCOs or Sinorhizobium meliloti inoculation in Medicago truncatula remains poorly understood. In this study, using a fluorescence-based CK sensor (pTCSn::nls:tGFP), we performed a high-resolution tissue-specific temporal characterization of the sequential activation of CK response during root infection and nodule development in M. truncatula after inoculation with S. meliloti. Loss-of-function mutants of the CK-biosynthetic gene ISOPENTENYLTRANSFERASE 3 (IPT3) showed impairment of nodulation, suggesting that IPT3 is required for nodule development in M. truncatula. Simultaneous live imaging of pIPT3::nls:tdTOMATO and the CK sensor showed that IPT3 induction in the pericycle at the base of nodule primordium contributes to CK biosynthesis, which in turn promotes expression of positive regulators of nodule organogenesis in M. truncatula., Precise spatial and temporal characterization of cytokinin (CK) responses reveals the function of the CK biosynthesis gene ISOPENTENYLTRANSFERASE 3 during nodule development in Medicago truncatula.

Successful plant organ development depends on well-coordinated intercellular communication between the cells of the organ itself, as well as with surrounding cells. Intercellular signals often move via the symplasmic pathway using plasmodesmata. Intriguingly, brief periods of symplasmic isolation may also be necessary to promote organ differentiation and functionality. Recent findings suggest that symplasmic isolation of a subset of parental root cells and newly forming lateral root primordia (LRPs) plays a vital role in modulating lateral root development and emergence. In this opinion article we discuss how two symplasmic domains may be simultaneously established within an LRP and its overlying cells, and the significance of plasmodesmata in this process.

In high-latitude regions, the cold hardiness of buds and canes of grapevine is important for budburst time and yield in the next season. The freezing resistance of buds and canes sampled from six wine grapes currently cultivated in Hokkaido, Japan, all of them grown from autumn to winter, was investigated. A significant difference between the cultivars in their freezing resistance was detected in the buds harvested in winter. In addition, outstanding differences in the lower temperature exotherms (LTE) related to the supercooling ability of tissue cells happened in the winter buds, and there is a close relationship between freezing resistance and LTE detected in the winter buds. This suggests that the supercooling ability of tissue cells in winter buds is strongly related to the freezing resistance. However, detailed electron microscopy exposed that the differences in freezing resistance among cultivars appeared in freezing behavior of leaf primordium rather than apical meristem. This indicated that as the water mobility from the bud apical meristem to the spaces around the cane phloem progressed, the slightly dehydrated cells improved the supercooling ability and increased the freezing resistance.

Summary Single‐cell RNA‐seq (scRNA‐seq) has been highlighted as a powerful tool for the description of human cell transcriptome, but the technology has not been broadly applied in plant cells. Herein, we describe the successful development of a robust protoplast cell isolation system in the peanut leaf. A total of 6,815 single cells were divided into eight cell clusters based on reported marker genes by applying scRNA‐seq. Further, a pseudo‐time analysis was used to describe the developmental trajectory and interaction network of transcription factors (TFs) of distinct cell types during leaf growth. The trajectory enabled re‐investigation of the primordium‐driven development processes of the mesophyll and epidermis. These results suggest that palisade cells likely differentiate into spongy cells, while the epidermal cells originated earlier than the primordium. Subsequently, the developed method integrated multiple technologies to efficiently validate the scRNA‐seq result in a homogenous cell population. The expression levels of several TFs were strongly correlated with epidermal ontogeny in accordance with obtained scRNA‐seq values. Additionally, peanut AHL23 (AT‐HOOK MOTIF NUCLEAR LOCALIZED PROTEIN 23), which is localized in nucleus, promoted leaf growth when ectopically expressed in Arabidopsis by modulating the phytohormone pathway. Together, our study displays that application of scRNA‐seq can provide new hypotheses regarding cell differentiation in the leaf blade of Arachis hypogaea. We believe that this approach will enable significant advances in the functional study of leaf blade cells in the allotetraploid peanut and other plant species.

Primordia formation is the first and most critical step in the development of fruiting bodies of edible fungi. In this study, the effects of exogenous ascorbic acid (ASA) on the Pleurotus ostreatus mycelia growth and primordia formation were researched and the results showed that the growth rate of P. ostreatus mycelia was accelerated and the time of primordia formation was advanced. The protein content and ascorbate oxidase (AAO) activity analysis showed that with the increase of ASA concentration, the protein content of mycelia first decreased and then increased, and in a certain concentration range, exogenous ASA could significantly promote the activity of AAO. Further expression analysis of the development regulating genes (Pofst3 and Pofst4) as well as blue light receptor coding genes (PoWC-1 and PoWC-2) showed the expression levels of those four genes all changed after the exogenous ASA addition, which indicated that the expression changes of PoWC-1 and PoWC-2, two key genes in the light morphogenesis, might affect the expression levels of development regulating genes Pofst3 and Pofst4, so as to lead to the formation of primordia in advance.

To overcome nitrogen deficiency, legume roots establish symbiotic interactions with nitrogen-fixing rhizobia that are fostered in specialized organs (nodules). Similar to other organs, nodule formation is determined by a local maximum of the phytohormone auxin at the primordium site. However, how auxin regulates nodule development remains poorly understood. Here, we found that in soybean, (Glycine max), dynamic auxin transport driven by PIN-FORMED (PIN) transporter GmPIN1 is involved in nodule primordium formation. GmPIN1 was specifically expressed in nodule primordium cells and GmPIN1 was polarly localized in these cells. Two nodulation regulators, (iso)flavonoids trigger expanded distribution of GmPIN1b to root cortical cells, and cytokinin rearranges GmPIN1b polarity. Gmpin1abc triple mutants generated with CRISPR-Cas9 showed the impaired establishment of auxin maxima in nodule meristems and aberrant divisions in the nodule primordium cells. Moreover, overexpression of GmPIN1 suppressed nodule primordium initiation. GmPIN9d, an ortholog of Arabidopsis thaliana PIN2, acts together with GmPIN1 later in nodule development to acropetally transport auxin in vascular bundles, fine-tuning the auxin supply for nodule enlargement. Our findings reveal how PIN-dependent auxin transport modulates different aspects of soybean nodule development and suggest that the establishment of auxin gradient is a prerequisite for the proper interaction between legumes and rhizobia., In soybean, nodule primordium formation involves GmPIN1-mediated polar auxin transport within primordium cells, and nodule enlargement involves the collaboration of GmPIN9d and GmPIN1-dependent auxin transport within nodule vasculature.

The developmental patterns of many organisms are orchestrated by the diffusion of factors. Here, we report a novel pattern on plant stems that appears to be controlled by inhibitor diffusion. Prickles on rose stems appear to be randomly distributed, but we deciphered spatial patterns of prickles on Rosa hybrida cv. ‘Red Queen’ stem. The prickles primarily emerged at 90 to 135 degrees from the spiral phyllotaxis that connected leaf primordia. We proposed a simple mathematical model that explained the emergence of the spatial patterns and reproduced the prickle density distribution on rose stems. We confirmed the model can reproduce the observed prickle patterning on stems of other plant species using other model parameters. These results indicated that the spatial patterns of prickles on stems of different plant species are organized by similar systems. Rose cultivation by humans has a long history. However, prickle development is still unclear and this is the first report of prickle spatial pattern with a mathematical model. Comprehensive analysis of the spatial pattern, genome, and metabolomics of other plant species may lead to novel insights for prickle development.

Plant leaves display considerable variation in shape. Here, we introduce key aspects of leaf development, focusing on the morphogenetic basis of leaf shape diversity. We discuss the importance of the genetic control of the amount, duration, and direction of cellular growth for the emergence of leaf form. We highlight how the combined use of live imaging and computational frameworks can help conceptualize how regulated cellular growth is translated into different leaf shapes. In particular, we focus on the morphogenetic differences between simple and complex leaves and how carnivorous plants form three-dimensional insect traps. We discuss how evolution has shaped leaf diversity in the case of complex leaves, by tinkering with organ-wide growth and local growth repression, and in carnivorous plants, by modifying the relative growth of the lower and upper sides of the leaf primordium to create insect-digesting traps.

The aluminum in acid soils is very rhizotoxic to most plant species, but it is essential for root growth and development in Camellia sinensis. However, the molecular basis of Al-mediated signaling pathways in root regeneration of tea plants is largely unclear. In this study, we profiled the physiological phenotype, transcriptome, and phytohormones in the process using stems treated with Al (0.3 mM) and control (0.02 mM). The anatomical analysis showed that the 0.3 mM Al-treated stem began to develop adventitious root (AR) primordia within 7 days, ARs occurred after 21 days, while the control showed a significant delay. We further found that the expression patterns of many genes involved in the biosynthesis of ZT, ACC, and JA were stimulated by Al on day 3; also, the expression profiles of auxin transporter-related genes were markedly increased under Al during the whole rooting process. Moreover, the expression of these genes was strongly correlated with the accumulation of ZT, ACC, JA, and IAA. CsERFs, CsMYBs, and CsWRKYs transcription factor genes with possible crucial roles in regulating AR regeneration were also uncovered. Our findings suggest that multiple phytohormones and genes related to their biosynthesis form a hierarchical transcriptional cascade during Al-induced de novo root regeneration in tea nodal cuttings.

The molecular basis of the competence of the pericycle cell to initiate lateral root primordium formation is totally unknown. Here, we report that in Arabidopsis, two types of basic helix-loop-helix (bHLH) transcription factors, named PERICYCLE FACTOR TYPE-A (PFA) proteins and PERICYCLE FACTOR TYPE-B (PFB) proteins, govern the competence of pericycle cells to initiate lateral root primordium formation. Overexpression of PFA genes confers hallmark pericycle characteristics, including specific marker gene expression and auxin-induced cell division, and multiple loss-of-function mutations in PFA genes or the repression of PFB target genes results in the loss of this specific pericycle function. PFA and PFB proteins physically interact and are under mutual- and self-regulation, forming a positive feedback loop. This study unveils the transcriptional regulatory system that determines pericycle participation in lateral root initiation. In Arabidopsis, xylem pole pericycle cells produce lateral roots. Here, two subfamilies of bHLH transcription factors are characterized. They confer to these pericycle cells the ability to re-activate cell division and initiate lateral roots.

Legume biological nitrogen fixation (BNF) is the most important N source in agricultural ecosystems. Nodule organogenesis from the primordia to the development of mature nodules with the ability to fix N2 largely determines BNF capacity. However, nodule growth is often limited by low phosphorus (P) availability, while the mechanisms underlying nodule development responses to P deficiency remain largely unknown. In this study, we found that nodule enlargement is severely inhibited by P deficiency, as reflected by the smaller individual nodule size from a soybean core collection in the field. Wide-ranging natural diversity in nodule size was further identified in soybeans reared in low P soils, with the FC-1 genotype outperforming FC-2 in assessments of nodulation under low P conditions. Among β-expansin members, GmINS1 expression is most abundantly enhanced by P deficiency in FC-1 nodules, and its transcript level is further displayed to be tightly associated with nodule enlargement. Four single nucleotide polymorphisms discovered in the GmINS1 promoter distinguished the FC-1 and FC-2 genotypes and accounted for the differential expression levels of GmINS1 responses to P deficiency. GmINS1 overexpression led to increases in nodule size, infected cell abundance, and N2 fixation capacity and subsequently promoted increases in N and P content, soybean biomass, and yield. Our findings provide a candidate gene for optimizing BNF capacity responses to low P stress in soybean molecular breeding programs.

The life cycle of the nematode Cosmocerca ornata (Dujardin, 1845)—a parasite of amphibians—was studied for the first time. The experimental infection of yearlings of the marsh frog Pelophylax ridibundus infected by larvae of C. ornata was performed. The development stages of parasites in the host were studied. It has been revealed that amphibians are infected with infectious larvae (J3) of nematodes in the surface-water layer by the penetration of parasites through eyes onto the conjunctiva under the lower eyelid, where the larvae undergo the third and fourth molting. Then the parasites migrate into the oropharyngeal cavity and through the digestive tract to the place of constant localization: the posterior part of the intestine. Morphological descriptions and original drawings of J3 and J4 juveniles, molting juveniles, and adults of C. ornata are given. The development stages of the juveniles are diagnosed by the body size, location of the genital primordium, and forming copulative structure. The sex of the nematodes can be identified at the third molt stage. Mature nematodes differ from juveniles by the presence of copulative organs: the vulva in adult females and spicules in adult males. The time of the development stages of C. ornata and the total life span of the parasite in the host is determined. The effect of ambient temperature on the period of development of nematodes in amphibians is established.

Arabidopsis ANT and AIL6 directly regulate genes involved in different aspects of early flower development including genes that specify floral organ identity and those that regulate growth and vascular development., Arabidopsis flower primordia give rise to organ primordia in stereotypical positions within four concentric whorls. Floral organ primordia in each whorl undergo distinct developmental programs to become one of four organ types (sepals, petals, stamens, and carpels). The Arabidopsis transcription factors AINTEGUMENTA (ANT) and AINTEGUMENTA-LIKE6 (AIL6) are required for correct positioning of floral organ initiation, contribute to the specification of floral organ identity, and regulate the growth and morphogenesis of developing floral organs. To gain insight into the molecular mechanisms by which ANT and AIL6 contribute to floral organogenesis, we identified the genome-wide binding sites of both ANT and AIL6 in stage 3 flower primordia, the developmental stage at which sepal primordia become visible and class B and C floral homeotic genes are first expressed. AIL6 binds to a subset of ANT sites, suggesting that AIL6 regulates some but not all of the same target genes as ANT. ANT- and AIL6-binding sites are associated with genes involved in many biological processes related to meristem and flower organ development. Comparison of genes associated with both ANT and AIL6 ChIP-Seq peaks and those differentially expressed after perturbation of ANT and/or AIL6 activity identified likely direct targets of ANT and AIL6 regulation. These include class B and C floral homeotic genes, growth regulatory genes, and genes involved in vascular development.

Phyllotactic diversity and developmental transitions between phyllotactic patterns are not fully understood. The plants studied so far, such as Magnolia, Torreya or Abies, are not suitable for experimental work, and the most popular model plant, Arabidopsis thaliana, does not show sufficient phyllotactic variability. It has been found that in common verbena (Verbena officinalis L.), a perennial, cosmopolitan plant, phyllotaxis differs not only between growth phases in primary transitions but also along the indeterminate inflorescence axis in a series of multiple secondary transitions. The latter are no longer associated with the change in lateral organ identity, and the sequence of phyllotactic patterns is puzzling from a theoretical point of view. Data from the experiments in silico, confronted with empirical observations, suggest that secondary transitions might be triggered by the cumulative effect of fluctuations in the continuously decreasing bract primordia size. The most important finding is that the changes in the primary vascular system, associated with phyllotactic transitions, precede those taking place at the apical meristem. This raises the question of the role of the vascular system in determining primordia initiation sites, and possibly challenges the autonomy of the apex. The results of this study highlight the complex relationships between various systems that have to coordinate their growth and differentiation in the developing plant shoot. Common verbena emerges from this research as a plant that may become a new model suitable for further studies on the causes of phyllotactic transitions.

Premise As a leaf expands, its shape dynamically changes. Previously, we documented an allometric relationship between vein and blade area in grapevine leaves. Larger leaves have a smaller ratio of primary and secondary vein area relative to blade area compared to smaller leaves. We sought to use allometry as an indicator of leaf size and plasticity. Methods We measured the ratio of vein-to-blade area from the same 208 vines across four growing seasons (2013, 2015, 2016, and 2017). Matching leaves by vine and node, we analyzed the correlation between the size and shape of grapevine leaves as repeated measures with climate variables across years. Results The proportion of leaf area occupied by vein and blade exponentially decreased and increased, respectively, during leaf expansion making their ratio a stronger indicator of leaf size than area itself. Total precipitation and leaf wetness hours of the previous year but not the current showed strong negative correlations with vein-to-blade ratio, whereas maximum air temperature from the previous year was positively correlated. Conclusions Our results demonstrate that vein-to-blade ratio is a strong allometric indicator of leaf size and plasticity in grapevines measured across years. Grapevine leaf primordia are initiated in buds the year before they emerge, and we found that total precipitation and maximum air temperature of the previous growing season exerted the largest statistically significant effects on leaf morphology. Vein-to-blade ratio is a promising allometric indicator of relationships between leaf morphology and climate, the robustness of which should be explored further.

Phytohormones participate in various processes over the course of a plant's lifecycle. In addition to the five classical phytohormones (auxins, cytokinins, gibberellins, abscisic acid, and ethylene), phytohormones such as brassinosteroids, jasmonic acid, salicylic acid, strigolactones, and peptides also play important roles in plant growth and stress responses. Given the highly interconnected nature of phytohormones during plant development and stress responses, it is challenging to study the biological function of a single phytohormone in isolation. In the current Review, we describe the combined functions and signaling cascades (especially the shared points and pathways) of various phytohormones in leaf development, in particular, during leaf primordium initiation and the establishment of leaf polarity and leaf morphology as well as leaf development under various stress conditions. We propose a model incorporating the roles of multiple phytohormones in leaf development and stress responses to illustrate the underlying combinatorial signaling pathways. This model provides a reference for breeding stress-resistant crops.

StCDPK2 is an early player in the salt stress response in potato plants; its overexpression promoted ROS scavenging, chlorophyll stability, and the induction of stress-responsive genes conferring tolerance to salinity. The salinity of soils affects plant development and is responsible for great losses in crop yields. Calcium-dependent protein kinases (CDPKs) are sensor–transducers that decode Ca2+ signatures triggered by abiotic stimuli and translate them into physiological responses. Histochemical analyses of potato plants harboring StCDPK2 promoter fused to the reporter gene β-glucuronidase (ProStCDPK2:GUS) revealed that GUS activity was high in the leaf blade and veins, it was restricted to root tips and lateral root primordia, and was observed upon stolon swelling. Comparison with ProStCDPK1:GUS and ProStCDPK3:GUS plants revealed their differential activities in the plant tissues. ProStCDPK2:GUS plants exposed to high salt presented enhanced GUS activity in roots which correlated with the numerous stress-responsive sites predicted in its promoter sequence. Moreover, StCDPK2 expression increased in in vitro potato plants after 2 h of high salt exposure and in greenhouse plants exposed to a dynamic stress condition. As inferred from biometric data and chlorophyll content, plants that overexpress StCDPK2 were more tolerant than wild-type plants when exposed to high salt. Overexpressing plants have a more efficient antioxidant system; they showed reduced accumulation of peroxide and higher catalase activity under salt conditions, and enhanced expression of WRKY6 and ERF5 transcription factors under control conditions. Our results indicate that StCDPK2 is an early player in the salt stress response and support a positive correlation between StCDPK2 overexpression and tolerance towards salt stress.

The initiation pattern of the floral organs of the Astragalus species displays uniqueness at the initial stages of ontogeny. However, its most common way is unidirectional initiation, which occurs from the abaxial to the adaxial sides. The overlapping of organs and the emergence of common primordia shortens the time of development and is of an evolutionary advantage to the genus. Astragalus species are constantly evolving, and they are bestowed with unique floral ontogeny that offers various advantages to these plants to survive and adapt to changing environmental conditions. The morphological features of the floral organ production of four Astragalus species were identical in the early and middle stages of development. During the middle and the late stages, some unique features such as rolled petals, sticky keel tips, diadelphous androecium were observed. Semi-circular receptacular nectaries were found in Astragalus henryi. Comparison of the inflorescence development between A. henryi and A. membranaceus revealed that A. membranaceus formed one terminal inflorescence, which developed into a raceme while A. henryi formed a variety of terminal inflorescences, branched by racemes to form panicles. Development of common primordia and organ overlap was also observed in both Oxytropis ochrocephala and Astragalus species. However, the most significant difference was observed in the keel petals of O. ochrocephala, which developed a beak at the later stages of development. The study unravels interesting relationships between four species of Astragalus and one species of Oxytropis. Study of floral ontogeny through series of sections using various microscopic techniques provided insights into the understudied floral traits of the genera. Such studies also need to be corroborated with other empirical evidence and analyses.

A common morphological feature of typical angiosperms is the patterning of lateral organs along primary axes of asymmetry—a proximodistal, a mediolateral, and an adaxial–abaxial axis. Angiosperm leaves usually have distinct adaxial–abaxial identity, which is required for the development of a flat shape. By contrast, many unifacial leaves, consisting of only the abaxial side, show a flattened morphology. This implicates a unique mechanism that allows leaf flattening independent of adaxial–abaxial identity. In this study, we report a role for auxin in outgrowth of unifacial leaves. In two closely related unifacial-leaved species of Juncaceae, Juncus prismatocarpus with flattened leaves, and Juncus wallichianus with transversally radialized leaves, the auxin-responsive gene GLYCOSIDE HYDROLASE3 displayed spatially different expression patterns within leaf primordia. Treatment of J. prismatocarpus seedlings with exogenous auxin or auxin transport inhibitors, which disturb endogenous auxin distribution, eliminated leaf flatness, resulting in a transversally radialized morphology. These treatments did not affect the radialized morphology of leaves of J. wallichianus. Moreover, elimination of leaf flatness by these treatments accompanied dysregulated expression of genetic factors needed to specify the leaf central-marginal polarity in J. prismatocarpus. The findings imply that lamina outgrowth of unifacial leaves relies on proper placement of auxin, which might induce initial leaf flattening and subsequently act to specify leaf polarity, promoting further flattening growth of leaves.

K, P, Cl, and Ca are distributed in tissue-specific patterns in Zea mays seedlings. These elements were mapped and analyzed using a relatively simple semi-quantitative technique, i.e., fast freezing, followed by freeze fracturing, then freeze drying, and finally scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS). In the radicle, endogenously derived (i.e., from seed) K and P transition from being homogenous in the apical meristem to tissue-specific in older regions. At 3 mm from the radicle apex, K concentration is approximately 40 mM in mid-cortex and decreases by approximately 50% at 15 mm. From 3 to 55 mm, P concentration in pericycle is approximately twice that found in adjacent regions. Ca is not detectable in younger portions of the radicle by SEM/EDS, but in older regions, it is present at 13 mM in mid-cortex. K concentration values of entire radicles analyzed with inductively coupled plasma optical emission spectrometry (ICP-OES) exceeded the SEM/EDS values. For Ca, the reverse was true. But, SEM/EDS analysis did not include several vascular tissues that contained high concentrations of K and low concentrations of Ca. The inception of lateral root primordia was accompanied by a localized decrease in Ca in cortical regions that were centrifugal to the primordium tip. A region of O-rich cells in endosperm was identified centripetal to the aleurone. These results indicate that (1) outer, mid-, and inner cortical regions, as well as the adjacent tissues, have distinct ion accumulation properties, and (2) ions are concentrated in some radicle tissues prior to development of Casparian strips.

Free-living filamentous thalli derived from an Analipus japonicus erect thallus were established in laboratory culture. The filamentous thalli were composed of slender filaments and densely pigmented oval or sub-oval cell masses. Temperature (5–20 °C) and irradiance (25–200 μmol photons m−2 s−1) effects on formation and growth of the thalli from three explant groups (isolated filaments, small cell masses, and large cell masses) were investigated for 15 days. These explants survived over the examined range. The isolated filaments had a high ability to form the thalli, and the isolated and new filaments formed filaments and cell masses. Meanwhile, the isolated and new cell masses formed only filaments, and their ability to grow and form the thalli decreased as they grew in size. Optimum culture conditions for formation and growth of the thalli from the isolated filaments, and the two cell mass growths were 15–20 °C and 100–200 μmol photons m−2 s−1. To produce erect thalli, the filamentous thalli were cultured on seedling threads for 6 weeks at 15 °C, 60 μmol photons m−2 s−1 and 20 cm s−1 water flow velocity. Erect axis density increased with increasing coverage of the filamentous thalli, and their cell masses (primordia of erect thallus holdfast) with mean area of about 140 × 103 μm2 began to produce erect axes. After 4 months of field cultivation, they grew into full-grown erect thalli of about 20 cm long. These findings show that the free-living filamentous thalli were applicable for stable seedling production of A. japonicus to be used in aquaculture.

The current study was designed to describe the prenatal developmental stages of the rabbit tongue. Thirty-five embryos of prenatal ages (E16, E19, E23, E25, E28, and Postnatal) were obtained from New Zealand white (NZW) rabbit. The primordia of the tongue were observed on the foundation as early as day 16 prenatal age (E16). The first primordia of lingual papillae were observed that including the primordia of circumvallate papillae at day 19 prenatal (E19). Thickenings of lingual epithelium developed at 19 day prenatal of embryo. At day 23-25 pc, the presence of primordia of foliate papillae was shown in addition to primordia of the fungiform and filiform papillae were found. The development of the final shape of the tongue is a longstanding process that occurs during the prenatal and postnatal life. The first primordia of gustatory papillae appear, and only later primordia of mechanical papillae are formed. In conclusion, the morphogenesis of the tongue and its lingual papillae discussed its herbivorous nature of feeding.

We identified a RING-type E3 ligase (TaBAH1) protein in winter wheat that targets TaSAHH1 for degradation and might be involved in primordia development by regulating targeted protein degradation. Grain yield per spike in wheat (Triticum aestivum), is mainly determined prior to flowering during mature primordia development; however, the genes involved in primordia development have yet to be characterized. In this study, we demonstrated that, after vernalization for 50 days at 4 °C, there was a rapid acceleration in primordia development to the mature stages in the winter wheat cultivars Keumgang and Yeongkwang compared with the Chinese Spring cultivar. Although Yeongkwang flowers later than Keumgang under normal condition, it has the same heading time and reaches the WS9 stage of floral development after vernalization for 50 days. Using RNA sequencing, we identified candidate genes associated with primordia development in cvs. Keumgang and Yeongkwang, that are differentially expressed during wheat reproductive stages. Among these, the RING-type E3 ligase TaBAH1 (TraesCS5B01G373000) was transcriptionally upregulated between the double-ridge (WS2.5) stage and later stages of floret primordia development (WS10) after vernalization. Transient expression analysis indicated that TaBAH1 was localized to the plasma membrane and nucleus and was characterized by self-ubiquitination activity. Furthermore, we found that TaBAH1 interacts with TaSAHH1 to mediate its polyubiquitination and degradation through a 26S proteasomal pathway. Collectively, the findings of this study indicate that TaBAH1 might play a prominent role in post-vernalization floret primordia development.

Objective The aim: The paper was aimed at the study of the processes of mineralization of the enamel of the permanent tooth after its eruption. Patients and methods Materials and methods: To study the structure of the enamel of permanent teeth has been carried out using light and electron microscopy. The study of the process of the development of the primordia of the permanent teeth involved 10 culled puppies of 30-40 days of age. Microscopic, electron microscopic, immunohistochemical methods of research have been used to study the processes of histogenesis. Results Results: The studies show that in the postnatal period, the formation of the crown, externally covered with cuticular epithelium, marks the formation of the primordium of the permanent tooth at the follicle stage. After eruption of a tooth, different parts of its crown have three individual structural and functional barriers to enamel biomineralization. The first one is provided by the cuticular epithelium of the pitted areas of the crown, which ensures filtering of the salivary fluid from the protein deposit in the form of a pellicle. The second barrier is defined on the lateral and cuspidate surfaces of the enamel, where the cuticle is erased or poorly expressed. The third structural and functional barrier of enamel biomineralization is located in the cervical portion of teeth of different classes. Conclusion Conclusions: Different areas of the enamel in the tooth crown have specific filtration barriers, which can be distinguished as follows: pit-and-fissure-and-groove, cuspidateand-approximal, and cervical barriers. The cuticle is poorly expressed or totally absent on the cusps of the tooth crowns in contrast to pitted areas.

Due to the increase in consumption and the possibilities of exportation and industrialization, blueberry cultivation has been expanding in Brazil. Since Rabbiteye is one of the more cultivated groups of blueberries in Brazil, this study aimed to assess the productive characterization of the blueberry cultivar Bluegem, group Rabbiteye. Assessments were conducted with plants in full production during two harvest seasons. We collected data on the following variables: flower and vegetative bud distribution, open flowers and formed fruit in two different shoot lengths, and number of floral primordia. The results showed a greater number of vegetative buds and the intercalation between flower and vegetative buds in a proportion of 78% and 48% in long and short shoots, respectively. The number of total buds and the number of flower and vegetative buds were influenced by the harvest season and the shoot length. The number of floral primordia was influenced by the bud position on the shoot, but not by the harvest season. The number of flowers and fruits, in general, was greater in apical buds and in long shoots.