Number Of Vascular Bundles Research Articles

Anatomía del pecíolo de 16 especies de Polypodiaceae presentes en México

Background and aims: Several works have shown that the petiole possesses useful anatomical characteristics for differentiating groups. Therefore, we carried out a descriptive and comparative anatomical study of the basal, middle, and apical regions of the petiole of 16 species belonging to 8 genera of Polypodioideae growing in Mexico, to identify anatomical characters that can contribute to their delimitation and identification M&M: Samples were collected from the basal, middle, and apical regions of the petiole and processed according to the paraffin embedding technique to obtain permanent preparations. The generated information was evaluated through a clustering analysis and a principal component analysis. Results: All petioles showed an unistratified epidermis, a cortex differentiated into external and internal, and vascular bundles with Polypodium-type distribution. Differences were registered in the petiole diameter, indument type, circumendodermal band, and number of vascular bundles. Four types of external cortex are recognized and the presence of nectaries in Campyloneurum amphostenon and C. costatum is reported for the first time, as well as the glandular hairs inserted at the base of the scales in Microgramma percussa. Identification keys were elaborated. Conclusions: The anatomical characteristics of the petiole allow us to differentiate taxonomically the genera and most of the species analyzed, the most important traits being the petiole diameter, the characteristics of the circumendodermal band, and the presence of aerophores and/or wings

Unraveling developmental patterns and differentiation trajectories in a single developing internode of Moso Bamboo (Phyllostachys edulis)

Bamboo, a significant carbon sink and eco-friendly resource, possesses substantial economic value and ecological benefits. A single internode represents the fundamental unit of bamboo culm, yet research focusing on the pivotal cellular destinies and molecular mechanisms underpinning the growth and development of a single internode remains comparatively scarce. In the study, we pioneered the establishment of a high-resolution single-cell transcriptomic atlas for a single internode of Moso bamboo. Utilizing known marker genes, we identified six major cell clusters (meristem, epidermis, phloem, xylem, pre-xylem/phloem, and vascular bundle sheath) and found many potential marker genes in the internode of Moso bamboo. Subsequently, we reconstructed the developmental trajectories of the epidermis and vascular tissues and further unveiled the key regulatory factors determining cell fates. Moreover, ectopic expression of PheIAA15 in Arabidopsis thaliana resulted in a marked reduction in the number of vascular bundles within the stems, as well as a significant decrease in their cross-sectional areas, diverging from existing research in Arabidopsis. The interaction between PheIAA15 and PheWOX4c suggested a potential novel auxin response mechanism in Moso bamboo. We subsequently elucidated that PheIAA15 bound to the promoter region of PheCLE25, thereby down-regulating the expression of PheCLE25, whereas PheWOX4c can activate the transcription of PheCLE25, which suggested that these two factors regulated the expression of PheCLE25 through an antagonistic mechanism. This finding highlighted the critical role of the complex regulatory network established among these elements in the differentiation of vascular tissues in the internodes of Moso bamboo. Overall, the study fills a critical research void concerning internodal development in bamboo plants at the single-cell level, laying a foundation for future studies to unravel the origin and differentiation of vascular bundle cells during internode development in perennial Gramineous plants.

Biosystematic studies of genus Withania Pauquy in Egypt

Withania (Solanaceae, Solanoideae) is a widespread genus. Comparative macro-, micro-morphological, anatomical, and molecular features of this genus in Egypt were examined using light and scanning electron microscopy to reassess the conflicted taxonomic relationships between the two studied species. The most significant morphological differences that have been found were: the shape of the lamina, apex, anther, and stigma, and the ratio of calyx tube/lobe; anatomical examination of taxonomic interest are as follows: number of vascular bundles, presence of ears and distribution of accessory vascular bundles in petiole and shape of spongy cells, and number of lower parenchyma in the midrib region of the leaf; trichomes of both species showed no significant differences; pollen, and seed characters are of taxonomic significance in differentiation and characterization between them. Protein profiling revealed that W. somnifera has only conserved proteins, while W. obtusifolia possessed both conserved and additional proteins in their SDS-PAGE banding patterns. Eleven starts codon-targeted (ScoT) primers were applied and produced 96 amplicons with an average of 70.83% polymorphism/primer. W. obtusifolia generated more polymorphic bands and maintained monomorphic ones. SDS-PAGE disclosed that both Withania species were 50% related. While Scot-Dendrogram revealed that both Withania species were poorly related. So, protein and molecular analyses showed considerable genetic variations between these two species.

Biogas slurry: A potential substance that synergistically enhances rapeseed yield and lodging resistance

Biogas slurry (BS) plays a vital role in improving the efficiency of crop production. On the flip side, the impact of BS on plant lodging factors and yield related traits is still obscure. Hence, we aimed to study the effects of pig and cow BS applications on yield formation, morpho-anatomical, mechanical, physiological properties and transcript expression patterns. The results showed that the yield and lodging resistance of rapeseed were synergistically improved via applying full BS dosage versus nitrogen fertilizer (CK). In addition, the seed yield was significantly increased by 23.9 % by promoting the dry matter accumulation and transport-ability, increasing number of pods by 8.4 % and 1000-seed weight by 5.1 %, respectively. Moreover, BS developed the stem mechanical strength by decreasing lodging index by 34.2 %, which was manifested by an increase in stem thickness and stiffness and a reduction in plant height. Besides, it enhanced the photosynthesis through promoting chlorophyll synthesis, delaying plant senescence, and accumulating N and K concentration. Anatomical observations revealed that BS increased greater number and area of stem vascular bundles, vessels, and maintained a dense microstructure than CK. Also, it boosted pectin, Ca2+ and K+ contents, which were significantly positively correlated with stem mechanical strength and reduced cellulose, lignin and hemicellulose contents. Meanwhile, correlation and structural equation modeling analysis validated the above results. Additionally, the differentially expressed genes were enriched in cell wall formation pathway, especially about the biosynthesis of pectin (PME, PG and PL), cellulose (CesA and CSL), lignin (PAL, POD, CCR, LAC and COMT) and hemicellulose (XTH and Xyl) were identified under BS. The above-mentioned results indicated that BS simultaneously affected lodging behavior by altering structural carbohydrates and modified yield composition by regulating dry-matter accumulation and allocation. This is the first comprehensive strategy on synchronizing rapeseed yield increase and lodging resistance under optimized BS management.

Biogenic zinc oxide nanoregulator determines the quantitative analysis of morpho‐anatomical and antioxidant capacity in Lactuca sativa L.

AbstractZinc oxide nanoparticles (ZnO NPs) can possibly serve as a pervasive source of essential nutrient zinc in agricultural crops in the future. The major environmental concerns with ZnO NPs might be their toxicity and incorrect dosage, which might lead to crop damage and environmental pollution. Interplay between ZnO NPs and Lactuca sativa (L. sativa) will be of interest, yet little is known about apropos interaction of these two, which will assist in optimizing the dose of ZnO NPs for their commercial use in agriculture. The current study aimed to investigate the growth, anatomical, and antioxidative responses of L. sativa against ZnO NPs and zinc acetate. ZnO NPs were foliar sprayed with concentrations of 0, 25, 50, and 100 ppm. ZnO NPs remarkably promoted L. sativa growth, leaf water content, and biomass accumulation; however, they declined root growth. The foliar spray of ZnO NPs improved the thickness of the stem hypodermis, cortex, pericycle, and phloem, while decreasing the stem diameter, thickness of the epidermis, and number of vascular bundles. ZnO NPs rigorously declined the cell area of xylem but slightly improved it in phloem. Unlike stem cells’ anatomical responses to ZnO NPs, the root cells behaved otherwise. Overall, the antioxidative activity of L. sativa considerably improved at 25 ppm concentration and decreased at 100 ppm. Generally, low and medium concentrations of ZnO NPs promoted plant morphological, anatomical, and antioxidant traits, while higher doses inhibited the same traits. Contrary to this, Zn acetate displayed severe toxic effects on almost all studied anatomical traits.

The REPLUMLESS Transcription Factor Controls the Expression of the RECEPTOR-LIKE CYTOPLASMIC KINASE VI_A2 Gene Involved in Shoot and Fruit Patterning of Arabidopsis thaliana.

The promoter of the RECEPTOR-LIKE CYTOPLASMIC KINASE VI_A2 (RLCK VI_A2) gene contains nine binding sites for the REPLUMLESS (RPL) transcription factor. In agreement, the expression of the kinase gene was strongly downregulated in the rpl-4 mutant. Comparing phenotypes of loss-of-function mutants, it was revealed that both genes are involved in stem growth, phyllotaxis, organization of the vascular tissues, and the replum, highlighting potential functional interactions. The expression of the RLCKVI_A2 gene from the constitutive 35S promoter could not complement the rpl-4 phenotypes but exhibited a dominant positive effect on stem growth and affected vascular differentiation and organization. The results also indicated that the number of vascular bundles is regulated independently from stem thickness. Although our study cannot demonstrate a direct link between the RPL and RLVKVI_A2 genes, it highlights the significance of the proper developmental regulation of the RLCKVI_A2 promoter for balanced stem development.

A transcriptional repressor HVA regulates vascular bundle formation through auxin transport in Arabidopsis stem.

Vascular bundles transport water and photosynthate to all organs, and increased bundle number contributes to crop lodging resistance. However, the regulation of vascular bundle formation is poorly understood in the Arabidopsis stem. We report a novel semi-dominant mutant with high vascular activity, hva-d, showing increased vascular bundle number and enhanced cambium proliferation in the stem. The activation of a C2H2 zinc finger transcription factor, AT5G27880/HVA, is responsible for the hva-d phenotype. Genetic, biochemical, and fluorescent microscopic analyses were used to dissect the functions of HVA. HVA functions as a repressor and interacts with TOPLESS via the conserved Ethylene-responsive element binding factor-associated Amphiphilic Repression motif. In contrast to the HVA activation line, knockout of HVA function with a CRISPR-Cas9 approach or expression of HVA fused with an activation domain VP16 (HVA-VP16) resulted in fewer vascular bundles. Further, HVA directly regulates the expression of the auxin transport efflux facilitator PIN1, as a result affecting auxin accumulation. Genetics analysis demonstrated that PIN1 is epistatic to HVA in controlling bundle number. This research identifies HVA as a positive regulator of vascular initiation through negatively modulating auxin transport and sheds new light on the mechanism of bundle formation in the stem.

The effect of an anatomical structure of a stem on pea lodging

Currently, in our country there is growing interest in the cultivation of high-tech pea varieties, which are characterized by uniform maturity, high productivity, and lodging resistance. Thus, breeding for lodging resistance is one of the most important criteria in pea breeding programs. The purpose of the current study was to search for anatomical indicators that could serve as a criterion when selecting pea samples for lodging resistance. The field trials were carried out in the fields of the laboratory for legumes breeding and seed production, the laboratory study was conducted in the laboratory for cell breeding of the FSBSI “ARC “Donskoy” in 2022–2023. The estimation of lodging resistance was carried out on 22 pea samples of the regional and foreign breeding. The studied samples differed in plant height, morpho-anatomical features of a stem structure, and lodging resistance. Based on the results of estimating an anatomical structure of a pea stem, there were identified such samples with a complex of traits (number of bundles, ratio of a number of bundles to stem tissues) as ‘Lu-153-06’, ‘G-1234’, ‘G-1193’, ‘G-1288’, ‘AKM’, ‘G-1313’, ‘Flagman 10’, ‘G-1313’. The analysis of correlations between anatomical indicators and field resistance to lodging has shown a high positive correlation with a stem height (r = 0.78±0.14), a mean negative correlation with a plant height (r = -0.66±0.17), and a mean positive correlation with a number of vascular bundles (r = 0.69±0.16). The experimental results allow concluding that the estimation of lodging resistance based on an anatomical structure of a pea stem is effective and can serve as a tester for lodging resistance.

A Modeling Approach to Studying the Influence of Grafting on the Anatomical Features and SAUR Gene Expression in Watermelons

Grafting alters the genetic and anatomical features of plants. Although grafting has been widely applied in plant propagation, the underlying processes that govern the effects of the procedure are not fully understood. Samples were collected to study the long-term influence of grafting on the leaf-shoot morphology, leaf-shoot anatomy, and genetic signature of the grafted plants. Citrulus lanatus (Thunb.) Matsum. & Nakai (cv. Lady) was used as the scion, and Lagenaria siceraria (Molina) Standl (cv. Argentario) as a rootstock. In grafted plants, leaf blades and petioles were 20.92% and 12.82% longer, respectively, while the midrib collenchyma was 35.68% thicker, and the diameter of the vessel member was 11.17% larger than in ungrafted plants. In the stem, grafting affected the arrangement and number of vascular bundles (from 1 to 2 rings). The thickness of the epidermis decreased by 69.79%, and the size of the external fascicular phloem decreased by 23.56%. The diameter of the vessel member of the grafted plants increased by 28.94%. Eight out of ten evaluated primers met the requirements (stability in both watermelons and bottle gourd, tissue-specific). In the genetic tests, we examined whether this change in the gene expression pattern is due to the grafting and, if so, to what extent. Seven out of eight tested Small Auxin Up-Regulated RNA (SAUR) genes were expressed in the ungrafted and grafted C. lanatus lines in four cases; the expression increased by more than 10% after grafting. The morpho-anatomical changes and genetic variation reported in this study for grafted lines of C. lanatus contribute to the understanding of the underlying mechanisms of plant growth observations resulting from grafting.

Histological Variations in Cucumber Grafted Plants and Their Effect on Yield

Cucumber is a vegetable crop of economic importance in Mexico. In 2023, fresh or frozen cucumber and pickle international sales reached USD 783M, placing Mexico in second rank among countries with the highest currency inflow in the world. This crop is mostly grown under protected environments with new production technologies, including rootstocks that are tolerant to biotic and abiotic factors that limit the yield and quality of the harvest. Therefore, the goal of this work was to assess three cucurbits as rootstocks (Cucurbita maxima, Cucurbita moschata and Citrullus lanatus), as well as studying the response of cucumber crop to the tested rootstocks. The following treatments were assessed: T1:PSP = cucumber Cv. Paraizo F1 without rootstock; T2:P/MA = cucumber grafted over Cucurbita maxima; T3:P/MO = cucumber grafted over Cucurbita moschata; T4:P/CL = cucumber grafted over Citrullus lanatus Citroides Var. The assessed variables included the number of fruits per plant (NFPP), fruit weight per plant (PFPP), average fruit weight (PPF), plant dry weight (PSP), xylem vessel area (AVX), number of xylem vessels (NVX), vascular bundle area (AHV) and number of vascular bundles (NHV) in roots (R), basal stalk (TB) and apical stalk (AT). Significant differences among treatments were found in the results for variables: NFPP, highlighting that T2:P/MA was superior by 46.15% versus T1:PSP and by 67.69% versus T3:P/MO. Regarding PFPP, T2:P/MA achieved the highest weight (5445 g), as it proved superior by 99.45% than the cucumber without rootstock (T1:PSP). Regarding PSP, T2:P/MA achieved the highest weight (196.65 g), significantly exceeding T1 by 137.5%. Regarding AVXR, T4:P/CL had the highest value (30,063 µm2). Regarding NHVR, watermelon had (T4:P/CL) 39.33% more vascular bundles than the root system of cucumber (T1:PSP). Treatments T2:P/MA and T4:P/CL had the highest values at AVXTB, while for variable NVXTB, treatments T3:P/MO and T2:P/MA were almost equal, surpassing non-grafted cucumber by 175.47%. However, T2:P/MA showed the greatest AHVTB, and T1:PSP was significantly superior to T3:P/MO, by 34.93%, for NHVTB. Furthermore, positive and significant correlations were found among PFPP, AHVR, and AVXTB, as well as among PSP, AVXTB, and AHVTB. Therefore, we may say that having a larger area of vascular vessels in the roots and a larger area of xylem vessels in the basal stalk leads to higher fruit yields per plant. In the same vein, the use of rootstocks is a sustainable alternative to increase fruit yield.

Characterization of an Excellent Hybrid Rice Restorer Line R382 with Enhanced Lodging Resistance

Hybrid rice needs to prevent lodging due to excessive grain weight during maturity, which can lead to yield loss, grain quality deterioration and difficulty in harvesting. Breeding excellent parents (restorer and male-sterile lines) is the foundation for cultivating lodging-resistant hybrid rice. However, there is still limited information about restorers with improved lodging resistance. To identify a new restorer with significantly enhanced resistance to lodging, the restorer line Huazhan, which has been used for many years in hybrid rice breeding in China, was used as the control, to evaluate the lodging resistance of the new restorer R382. A two-year field experiment was executed to investigate the difference on lodging-related traits of the basal two internodes above-ground, such as out diameters of stems with or without leaf sheath (DWS, DWOS), culm thickness (CT), the section modulus (SM), bending stress (BS), and bending moment at break (M). The results indicated that DWS, CT, BS, M of R382 was at least 19.9%, 13.3%, 36.5% and 52.6% higher than that of Huazhan. However, the negative indicator lodging index of R382 was over 17.5% lower. The number and area of vascular bundles, and the contents of the chemical components of the cell wall including cellulose, lignin, and hemicellulose, together with the accumulation of starch granules, were significantly greater in R382. Furthermore, in the basal stems during the jointing stage, a series of genes that promote cell wall formation exhibited significantly higher expression levels in R382. Meanwhile, there was no significant difference in the yield of R382 and Huazhan. Thus, this new restorer could be a valuable donor in the future hybrid rice breeding programs for improving lodging resistance.

Contributions of lignification, tissue arrangement patterns, and cross-sectional area to whole-stem mechanical properties in Arabidopsis thaliana.

Plant cells withstand mechanical stress originating from turgor pressure by robustly maintaining the mechanical properties of the cell wall. This applies at the organ scale as well; many plant stems act as pressurized cylinders, where the epidermis is under tension and inner tissues are under compression. The clavata3 de-etiolated3 (clv3-8 det3-1) double mutant of Arabidopsis thaliana displays cracks in its stems because of a conflict between the mechanical properties of the weak epidermis and over-proliferation of inner stem tissues. In this work, we conducted three-point bending tests on various Arabidopsis thaliana mutants, including those displaying the stem cracking phenotype, to examine the differences in their mechanical properties. The clv3-8 det3-1 double mutant exhibited reduced stem stiffness, consistent with reduced differentiation due to the clv3-8 mutation. Yet, in clv3-8, stem cross-sectionalarea was increased associating with the increase in vascular bundle number, and stem cross-sections displayed various shapes. To uncouple the contribution of geometry and cell-wall differentiation to the mechanical properties of the whole stems, we tested the contribution of lignified fibers to stem stiffness. In order to suppress lignin deposition in stems genetically, we generated multiple higher-order mutants by crossing clv3-8 and/or det3-1 with nst1-1 nst3-1, in which lignin deposition is suppressed. Stem stiffness was reduced markedly in all nst1-1 nst3-1 mutant backgrounds. Overall, our results suggest that stem stiffness relies on the presence of differentiated, lignified, fiber tissue as well as on the alignment or spatial distribution of vascular bundles within the stem organ.

SOME PHYSICAL AND MECHANICAL PROPERTIES OF COCONUT PALM (COCOS NUCIFERA) STEM IN HAINAN ISLAND, CHINA

The physical and mechanical properties of 40-year-old coconut stem were investigated in different radial directions and height positions. The results showed that in the radial direction, the properties of the number of vascular bundles (NVB), density, shrinkage, compressive strength parallel to the grain (CS), modulus of rupture (MOR), and modulus of elasticity (MOE) decreased continuously from the outer area to the inner area, except for the water absorption (WA) value which increased from the outer area to the inner area. The density and MOE decreased from the bottom to the top in the height direction while NVB and WA increased. The shrinkage, CS, and MOE first increased and then decreased from the bottom to the top. NVB in coconut stem affects the density and determines the main mechanical properties of CS, MOR, and MOE. The analysis of variance (two-way ANOVA) showed a significant difference in density, NVB, WA, CS, MOR, and MOE in radial direction and height position. These findings can be useful for the development of new applications for coconut stems, such as in construction, landscaping, or furniture manufacturing, as well as for improving our understanding of their structural characteristics.

Vascular system of rice leaves depending on ploidy level

The current paper has provided data on the study of the vascular system of flag leaves of rice plants grown in a greenhouse in the period 2022–2023. The objects of the study were 24 rice samples developed at the FSBSI “ARC “Donskoy” using the method of androgenesis and cell culture. The purpose of the work was to determine the degree of development of the vascular system of flag leaves of regenerated rice plants with different ploidy levels (1n, 2n, 4n). When studying the vascular system of plant leaves (the number and area of bundles), it was found that haploid plants had smaller vascular bundles compared to diand tetraploid samples. The average beam diameter had dimensions of 59.5, 69.3 and 75.3 µm, the area of one beam was 2815.6, 3827.2 and 4540.5 µm², respectively. In the leaves of rice samples, a larger number of small and large vascular bundles have been formed with increasing ploidy level. Their number was 36–44 in haploids, 40–52in diploids, 52–60 in tetraploids. The average number of bundles was 40.3, 46.6 and 55.2, respectively. The venation pattern was individual for each sample. Between single large bundles there are from one to seven small veins, most often 4–6 pieces. Thus, samples with different ploidy levels differ in the anatomical structure of the leaves, which ultimately affects their morphology and productivity.

WALL-ASSOCIATED KINASE Like 14 regulates vascular tissue development in Arabidopsis and tomato

Initiation of plant vascular tissue is regulated by transcriptional networks during development and in response to environmental stimuli. The WALL-ASSOCIATED KINASES (WAKs) and WAK-likes (WAKLs) are cell surface receptors involved in cell expansion and defence in cells with primary walls, yet their roles in regulation of vascular tissue development that contain secondary walls remains unclear. In this study, we showed tomato (Solanum lycopersicum) SlWAKL2 and the orthologous gene in Arabidopsis thaliana, AtWAKL14, were specifically expressed in vascular tissues. SlWAKL2-RNAi tomato plants displayed smaller fruit size with fewer seeds and vascular bundles compared to wild-type (WT) and over-expression (OE) lines. RNA-seq data showed that SlWAKL2-RNAi fruits down-regulated transcript levels of genes related to vascular tissue development compared to WT. Histological analysis showed T-DNA insertion mutant wakl14–1 had reduced plant stem length with fewer number of xylem vessels and interfascicular fibres compared to WT, with no significant differences in cellulose and lignin content. Mutant wakl14–1 also showed reduced number of vascular bundles in fruit. A proWAKL14::mCherry-WAKL14 fusion protein was able to complement wakl14–1 phenotypes and showed mCherry-WAKL14 associated with the plasma membrane. In vitro binding assays showed both SlWAKL2 and AtWAKL14 can interact with pectin and oligogalacturonides. Our results reveal novel roles of WAKLs in regulating vascular tissue development.

Biochar application improves the yield, lodging resistance, and lignin synthesis mechanism in rice

AbstractBiochar application elicits positive environmental and agricultural impacts owing to its physicochemical properties; however, the mechanism of biochar in regulating the lodging resistance in rice remains unclear. The present study was conducted to investigate the effects of biochar application on rice yield, lodging‐related traits, and enzymes activity and gene expression related to lignin biosynthesis in two rice (Oryza sativa L.) cultivars, that is, Shennong 265 and Akihikari. The biochar treatments were: 0 (B1), 5 (B2), 10 (B3), 20 (B4), and 40 (B5) t/ha. Results depicted that compared with B1, the B2 and B3 treatments improved the rice yield by 8.36%–27.62% and decreased the lodging index by 7.72%–24.14% for both rice cultivars, respectively. The increase in rice yield was mainly due to an increase in chlorophyll content, net photosynthesis, and dry matter at the heading stage. The reduced lodging index in B2 and B3 was mainly owing to an increase in stem lignin and silicon content by 28.55%–62.80% and 16.27%–50.09%, respectively, that was possibly linked to an increase in lignin synthase activity and its gene expression, that is, phenylalanine ammonia lyase, caffeic acid 3‐O‐methyltransferase, 4CL3 (where 4CL is 4‐coumarate: CoA ligase), and CCR20 (where CCR is cinnamyl coenzyme A reductase). Furthermore, the numbers of large and small vascular bundles were the highest in B2 and B3 treatment for both rice cultivars. However, excess biochar applications had an inhibitory effect on rice yield. Overall, biochar application at 5–10 t/ha is an appropriate dosage to improve lodging resistance and rice yield.

Morphological features and anatomical structure of the leaves of Dagestan endemic species of <i>Allium</i>

Aim. To conduct a comparative analysis and assessment of the taxon specificity of the morphological and anatomical features of the leaves of endemic species of the genus Allium in Dagestan. Material and Methods. The research materials were samples of endemic species of the genus Allium from the natural populations of mountainous Dagestan: A. daghestanicum; A. gunibicum; A. charadzeae; A. mirzojevii and A. samurense. For the analysis of morphometric features, 10 generative individuals were collected in the full flowering phase. Processing of the collected material was carried out at the Laboratory of Introduction and Genetic Resources of the Mountain Botanical Garden, Dagestan Federal Research Centre, Russian Academy of Sciences. Fixation of the material and preparation of temporary micropreparations were carried out according to the generally accepted methods of anatomical studies. Anatomical studies were carried out on leaves of medium formation from the middle part of the leaf. Morphometric parameters of tissues and cells were measured using a Levenhuk D870T optical microscope with an eyepiece micrometer. Micropreparations were photographed using a Lomo‐AT 054 optical microscope and a DCM 510 SCOP video eyepiece. Results. A grouping of species according to leaf size was carried out: large‐leaved (A. daghestanicum, A. gunibicum, A charadze section Dagestanica. Tscholok. Friesen) and small‐leaved (A. mirzojevii, A. samurense section Oreiprason F. Herm.), according to the shape of the leaf cross section: grooved with smooth edges (A. daghestanicum), grooved with ribbed edges (A. gunibicum and A charadze) and rounded ribbed (A. mirzojevii and A. samurense), according to the number and size of vascular bundles. Descriptions of the anatomical structure of the leaves and an assessment of the species specificity of the studied traits of five species of Allium were carried out. Conclusions. It was determined that some features of the morphology and anatomy of the leaves of five endemic species of the genus Allium are species‐specific or due to environmental conditions of growth in the arid conditions of Inner Mountain Dagestan.

Analyzing the structure of bamboo culms using computer vision and mechanical simulation

Abstract Bamboo culm is a natural material characterized by a graded structure of vascular bundles in the radial direction and a regular distribution of bamboo nodes in the axial direction. To investigate the adaptation of bamboo culm structure to its natural environment, the bamboo culm structure was analyzed using a vascular bundle identification model, complemented by mechanical simulations. The results showed a certain pattern in the macroscopic dimensional characteristics of bamboo from the base to the top: the outer diameter decreased linearly; the internode length initially increased before decreasing; the length-to-diameter ratio gradually increased; and the wall-to-cavity ratio initially decreased before increasing. In response to external forces, bamboo exhibited strong stability, which was attributed to the thin and hollow wall as well as parabolic distribution of bamboo nodes. Along the axial direction, vascular bundle numbers linearly decreased, while the ratio of fiber sheath tissue and the distribution frequency of vascular bundles increased from the base to the top. In the radial direction, the length and area of vascular bundles tended to increase before decreasing, while the width tended to increase, leading to a decreasing length-to-width ratio. Overall, the radial variation pattern of vascular bundles showed nonsignificant variations at different heights.

Modified TAL expression in rice plant regulates yield components and grain quality in a N-rate dependent manner

Context or problemHigher-yield and superior-quality rice are the major goals in rice breeding and nitrogen management. Genetic modification combined with optimal nitrogen (N) fertilization is expected to realize it. Objective or research questionModification in transaldolase (TAL) expression alters both the number and pattern of vascular bundles in rice plants, but its interactions with N rate remains unknown. MethodsWe employed three representative lines with different expression levels of TAL in the same genetic background (Wuyunjing 7, WT), and analyzed their responses in dry matter accumulation (DMA), carbohydrate transport, grain filling, yield, yield components, and grain quality under a wide range of N rate. ResultsIncreased expression of TAL (OE) promoted rice yield by producing more spikelets per panicle and higher 1000-grain weight, while decreased expression of TAL lowered the seed setting rate and grain weight significantly. Under a fixed N rate, when TAL expression was altered, the direct path coefficients of the seed setting rate and 1000-grain weight to the yield were higher than other yield components, especially at a high N rate. Decreased expression of TAL (RNAi) significantly reduced the starch and non-structural carbohydrates (NSC) contents in the stems, but enhanced the soluble sugar retention, whereas increased expression of TAL enhanced the translocation of NSC. The grain weight at maturity and mean grain-filling rate (mg d−1) increased significantly along with the TAL expression, but their differences among RNAi, WT and OE narrowed at higher N rate. Decreased expression of TAL enhanced the apparent amylose content (ACC) and protein (PC), reduced the starch granule size, and caused a loose starch arrangement and elevated chalkiness, as a consequence, significantly reduced the peak viscosity, hot viscosity, final viscosity, and taste value in a N rate dependent manner. The taste values of OE and WT were similar and the highest value was attained under a moderate N rate. ConclusionsTAL expression plays an important role in the regulation of assimilate supply, grain filling, yield formation, and grain quality. Increased expression of TAL alleviates competition effect among the yield components and enhances the yield potential, especially under moderate to high N rate. Higher TAL expression combined with a moderate N rate improves ECQ. Implications or significanceTAL expression and N rate interacts to regulate yield components and quality. This finding provides meaningful knowledge to administering N rate and genetically modifying TAL expression in a rice variety.

Drought priming at seedling stage improves photosynthetic performance and yield of potato exposed to a short-term drought stress

Potato (Solanum tuberosum L.) is an important food and vegetable crop worldwide. In recent years, the arid environment resulting from climate change has caused a sharp decline in potato yield. To clarify the effect of drought priming at the seedling stage on the tolerance of potato plants to drought stress during tuber expansion, we conducted a pot experiment to investigate the physiological response of the plants generated from seed potatoes of the variety ‘Favorita’ to varied water supply conditions: normal water supply at the seedling stage (control), normal water supply at the seedling stage and drought stress at the mid-tuber-expansion stage (non-primed), and drought priming at the seedling stage plus drought stress at the mid-tuber-expansion stage (primed). Drought priming resulted in an increase in the number of small vascular bundles in potato plants compared to non-primed plants. It also altered the shape and density of stomata, enhancing water use efficiency and reducing whole-plant transpiration. The primed plants maintained the basal stem cambium for a longer time under drought stress, which gained an extended differentiation ability to generate a greater number of small vascular bundles compared to non-primed plants. Drought priming increased the amount and rate of dry matter translocation, and so reduced the adverse effects on tubers of potato under drought stress. Therefore, drought priming at the seedling stage improved the photosynthetic performance and yield, and probably enhanced the drought tolerance of potato.