Small Vascular Bundles Research Articles

Vascular Bundle Characteristics of Different Rice Variety Treated with Nitrogen Fertilizers and Its Relation to Stem Assimilates Allocation and Grain Yield

The vascular bundle plays a vital role in photoassimilates transportation in rice. However, the vascular bundle characteristics of basal internode and its relationship with stem assimilates allocation and yield remain unclear. In this study, experiments with four different types of rice varieties subjected to three nitrogen application levels were conducted. The results showed that large vascular bundles (LVB) and small vascular bundles (SVB)-related traits of basal internode exhibited genotypic differences. Indica-japonica hybrid varieties had the highest number of cross sectional areas and phloem areas of LVB and SVB, thus the highest stem nonstructural carbohydrates (NSC) translocation, grain filling percentage and grain yield, followed by indica hybrid varieties and indica conventional varieties, and those were the lowest in japonica conventional varieties. The LVB and SVB related traits were significantly and positively correlated with stem NSC translocation, grain filling percentage and grain yield, respectively These results suggested that improving the characteristics of basal internodes was beneficial to enhance stem NSC translocation and consequently increase grain yield. Nitrogen application increased LVB and SVB related traits. Therefore, varieties with developed vascular bundles of basal internodes and cultivation techniques for improving vascular bundle related traits should be considered as the effective route for increasing grain yield.

Stem small vascular bundles have greater accumulation and translocation of non-structural carbohydrates than large vascular bundles in rice.

Phloem unloading and loading are associated with stem non-structural carbohydrates (NSCs) accumulation and remobilization in rice (Oryza sativa L.). Four rice recombinant inbred lines (R032, R191, R046, and R146) derived from a cross between Zhenshan 97 and Minghui 63 were used to investigate the contributions of stem large and small vascular bundles (SVBs) to NSCs accumulation and translocation. Before heading, the parenchyma cells in stem cortex tissues (PCs) surrounding SVBs had higher starch density than those surrounding large vascular bundles (LVBs). Moreover, the protein levels of sucrose transporters (SUTs), cell wall invertase, sucrose synthase, and adenosine diphosphate glucose pyrophosphorylase, as well as the phloem plasmodesma densities were higher in SVBs than those in LVBs. After heading, starch density decreased more in PCs surrounding SVBs than in LVBs. Also, the protein levels of SUTs, α-amylase, sucrose phosphate synthase and sucrose synthase, the phloem plasmodesma densities in SVBs were higher than those in LVBs. The correlations of the number and total cross-sectional area of SVBs with mass and contribution to yield of transferred NSCs were higher than those of LVBs. Our results suggest that SVBs may have higher contributions to pre-anthesis stem NSCs accumulation and post-anthesis translocation than LVBs, which is potentially attributed to the high level of protein and enzyme involved in stem unloading and loading via apoplastic and symplastic pathways.

Characterization of Stem Nodes Associated with Carbon Partitioning in Maize in Response to Nitrogen Availability.

Stem node has been found to be a hub for controlling mineral nutrient distribution in gramineous plants. However, the characteristics of stem nodes associated with whole-plant carbon partitioning in maize (Zea mays L.) and their responses to nitrogen (N) availability remains elusive. Maize plants were grown in greenhouse under low to high N supply. Plant growth, sugar accumulation, and sugar transporters in nodes and leaves, as well as the anatomical structure of nodes, were investigated at vegetative phase. When compared to N-sufficient plants, low-N availability stunted growth and resulted in 49–64% less sugars in leaves, which was attributed to low photosynthesis or the accelerated carbon export, as evidenced by more 13C detected further below leaf tips. Invariably higher sugar concentrations were found in the stem nodes, rather than in the leaves across N treatments, indicating a crucial role of nodes in facilitating whole-plant carbon partitioning. More and smaller vascular bundles and phloem were observed in stem nodes of N-deficient plants, while higher sugar levels were found in the bottom nodes than in the upper ones. Low-N availability upregulated the gene expressions of sugar transporters, which putatively function in nodes such as ZmSWEETs and ZmSUTs at the bottom stem, but suppressed them in the upper ones, showing a developmental impact on node function. Further, greater activity of sugar transporters in the bottom nodes was associated with less sugars in leaves. Overall, these results highlighted that stem nodes may play an important role in facilitating long-distance sugar transport in maize.

Characterization of Source–Sink Traits and Carbon Translocation in Maize Hybrids under High Plant Density

Both compact planting and selecting superior maize (Zea mays L.) hybrids can greatly optimize the source–sink relationship and enhance maize productivity. However, the underlying physiological mechanism for regulating carbon (C) assimilate transport and influencing grain yield between maize cultivars has remained unclear under contrasting plant densities. A two-year field experiment was conducted to investigate grain yield, vascular bundle character, grain filling, C allocation in grains and other tissues, and hormone level and enzyme activity in grains under 60,000 (ND) and 90,000 plants ha−1 (HD) densities using Xianyu 335 (XY335) and Zhengdan958 (ZD958) hybrids. Compared to the ZD958, XY335 increased grain yield, kernel number per plant (KNP), and sink capacity by 11.4%, 15.7%, and 7.4%, respectively. Moreover, XY335 performed higher net photosynthetic rate and sucrose synthase activities in grains than those in ZD958, and higher levels of sucrose phosphate synthase and soluble acid invertase activity were mainly exhibited in the middle of the grain filling stage, which contributed to increasing the proportion of grain in total dry matter, grain C content and leaf C transport efficiency by 4.3%, 12.2%, and 52.9%, respectively, under HD conditions. Additionally, a greater area and number of small vascular bundle in ear of XY335 resulted in 21.3% higher matter transport efficiency and 4.8% higher maximum grain filling rate than ZD958 under HD conditions. In addition, grains of XY335 exhibited generally higher levels of indole acetic acid (IAA) and abscisic acid (ABA), as well as ABA/GA3 ratio after maize pollination relative to those from ZD958, conducive to regulating C translocation from leaves to grains. Overall, our study illustrates that stronger source activity, sink characteristics, and matter transport channels for maize hybrids are significant for C assimilate transport to grain for achieving high grain yield under higher plant density.

Genetic Bases of Flow- and Sink-Related Traits in Rice Revealed by Genome-Wide Association Study

Rice yield is determined by source, sink, and flow and the coordination of these factors. However, the genetic base of the sink-flow is still unknown. We conducted on genome-wide association to detect quantitative trait loci (QTL) related to sink size (the number of rachis branches and spikelet number in rachis branches) and flow vascular bundle (large and small vascular bundles number in panicle neck and second internode) using 440 germplasm resources. The accessions exhibited marked variation in all traits and demonstrated complex phenotypic correlations. A total of 138 QTL affecting the 8 traits were detected using 3,188,500 high-quality single nucleotide polymorphism markers. Sixteen QTL clusters simultaneously affected flow and sink traits, which might explain the genetic base of significant correlations between flow and sink traits. The nine candidate genes in two consistent chromosomal regions simultaneously affecting multiple vascular bundle and sink size traits by performing gene-based association analysis and haplotype analysis. Among them, D2 (LOC_Os01g10040) and Gn1a (LOC_Os01g10110) for qPLVN1.1, qSLVN1.1, and qPRN1.2 and OsPIN5b (LOC_Os08g41720) for qPLVN8, qSLVN8, qSSVN8, and qSTSN8.2 were considered the most likely candidate genes based on functional annotations. The results provide useful information for improving rice yield potential via balancing sink–flow relationships by marker-assisted selection.

Dissection of the genetic architecture of peduncle vascular bundle-related traits in maize by a genome-wide association study.

SummaryThe peduncle vascular system of maize is critical for the transport of photosynthetic products, nutrients, and water from the roots and leaves to the ear. Accordingly, it positively affects the grain yield. However, the genetic basis of peduncle vascular bundle (PVB)‐related traits in maize remains unknown. Thus, 15 PVB‐related traits of 386 maize inbred lines were investigated at three locations (Yongcheng, 17YC; Kaifeng, 20KF; and Yuanyang, 20YY). The repeatability for the 15 traits ranged from 35.53% to 92.13%. A genome‐wide association study was performed and 69 non‐redundant quantitative trait loci (QTL) were detected, including 9, 41, and 27 QTL identified at 17YC, 20KF, and 20YY, respectively. These QTL jointly explained 4.72% (SLL) to 37.30% (NSVB) of the phenotypic variation. Eight QTL were associated with the same trait at two locations. Furthermore, four pleiotropic QTL were identified. Moreover, one QTL (qPVB44), associated with NSVB_20KF, was co‐localized with a previously reported locus related to kernel width, implying qPVB44 may affect the kernel width by modulating the number of small vascular bundles. Examinations of the 69 QTL identified 348 candidate genes that were classified in five groups. Additionally, 26 known VB‐related homologous genes (e.g. VLN2, KNOX1, and UGT72B3) were detected in 20 of the 69 QTL. A comparison of the NSVB between a Zmvln2 EMS mutant and its wild type elucidated the function of the candidate gene ZmVLN2. These results are important for clarifying the genetic basis of PVB‐related traits and may be useful for breeding new high‐yielding maize cultivars.

SDG128 is involved in maize leaf inclination.

Maize leaf angle (LA) is a complex quantitative trait that is controlled by developmental signals, hormones, and environmental factors. However, the connection between histone methylation and LAs in maize remains unclear. Here, we reported that SET domain protein 128 (SDG128) is involved in leaf inclination in maize. Knockdown of SDG128 using an RNA interference approach resulted in an expanded architecture, less large vascular bundles, more small vascular bundles, and larger spacing of large vascular bundles in the auricles. SDG128 interacts with ZmGID2 both invitro and invivo. Knockdown of ZmGID2 also showed a larger LA with less large vascular bundles and larger spacing of vascular bundles. In addition, the transcription level of cell wall expansion family genes ZmEXPA1, ZmEXPB2, and GRMZM2G005887; transcriptional factor genes Lg1, ZmTAC1, and ZmCLA4; and auxin pathway genes ZmYUCCA7, ZmYUCCA8, and ZmARF22 was reduced in SDG128 and ZmGID2 knockdown plants. SDG128 directly targets ZmEXPA1, ZmEXPB2, LG1, and ZmTAC1 and is required for H3K4me3 deposition at these genes. Together, the results of the present study suggest that SDG128 and ZmGID2 are involved in the maize leaf inclination.

Anatomy and Trichome Micromorphology of Endemic Ballota pseudodictamnus subsp. lycia (Lamiaceae)

In this study, the anatomical features of Ballota pseudodictamnus (L.) Benth. subsp. lycia Hub.-Mor. (Lamiaceae), endemic taxa from Turkey are examined and evaluated by light (LM) and scanning electron microscopy (SEM). Different trichome types (glandular -including Lamiaceae type, capitate and peltate- and non-glandular trichomes) are observed. The densest trichome type is dendroid trichomes on the aerial part of the plant. The leaf is bifacial and amphistomatic. In the petiole, there are two collateral vascular bundles in the centre and one small vascular bundle in each corner. The prismatic crystals are present in the pith area of the stem. Results are compared with other studies in the literature. The anatomical characteristics of the stem, petiole, lamina and measurements are presented additionally trichome micromorphology is given for the first time.

Genome-Wide Association Study of Vascular Bundle-Related Traits in Maize Stalk.

The vascular bundle plays an important role in nutrient transportation in plants and exerts great influence on crop yield. Maize is widely used for food, feed, and fuel, producing the largest yield in the world. However, genes and molecular mechanism controlling vascular bundle-related traits in maize have largely remained undiscovered. In this study, a natural population containing 248 diverse maize inbred lines genotyped with high-throughput SNP markers was used for genome-wide association study. The results showed that broad variations existed for the vascular bundle-related traits which are subject to genetic structure and it was suitable for association analysis. In this study, we identified 15, 13, 2, 1, and 5 SNPs significantly associated with number of small vascular bundle, number of large vascular bundle, average area of single small vascular bundle, average area of single large vascular bundle, and cross-sectional area, respectively. The 210 candidate genes in the confidence interval can be classified into ten biological processes, three cellular components, and eight molecular functions. As for the Kyoto Encyclopedia of Genes and Genomes analysis of the candidate genes, a total of six pathways were identified. Finally, we found five genes related to vascular development, three genes related to cell wall, and two genes related to the mechanical strength of the stalk. Our results provide the further understanding of the genetic foundation of vascular bundle-related traits in maize stalk.

Lignin metabolism regulates lodging resistance of maize hybrids under varying planting density

Hybrids and planting density are the main factors affecting maize lodging resistance. Here, we aimed to elucidate the mechanism of the regulation of maize lodging resistance by comparing two hybrids at various planting densities from the perspective of lignin metabolism. Our results showed that compared to lodging-susceptible hybrid Xundan 20 (XD20), lodging-resistant hybrid Denghai 605 (DH605) showed a lower center of gravity and culm morphological characteristics that contributed to the higher lodging resistance of this hybrid. Lignin content, activities of key lignin synthesis-related enzymes and G-, S- and H-type monomer contents were significantly higher in hybrid DH605 than in hybrid XD20. Stalk mechanical strength, lignin accumulation and enzyme activity decreased significantly with increasing planting density in the two hybrids. While G-type monomers first decreased with increasing planting density but then remained stable, S-type monomers showed a decreasing trend, and H-type monomers showed an increasing trend. Correlation analysis showed that lodging rate was significantly correlated with plant traits and lignin metabolism. Therefore, maize hybrids characterized by high lignin accumulation, high lignin synthesis-related activities, high S-type monomer content, low center of gravity, high stem puncture strength, high cortical thickness, and small vascular bundle area are more resistant to lodging. High planting densities reduce stalk lignin accumulation, relevant enzyme activities and mechanical strength, thereby, ultimately increasing the lodging rate significantly.

Yield-enhancing SPIKE allele from the aus-subtype indica rice and its allele specific codominant marker

Improving spikelet number without limiting panicle number is an important strategy to increase rice productivity. In this study, a spikelet number enhancing SPIKE-allele was identified from the aus subtype indica rice, cv. Bhutmuri, which has an identical japonica like corresponding sequence including a retrotransposon sequence, usually absent in indica genotypes, like IR64. An allele-specific singletube PCR-based codominant marker targeting an A/G single-nucleotide polymorphism (SNP) at the 3'UTR was identified for easier genotyping. The yield enhancing ability of the Bhutmuri-SPIKE allele carrying RILs and NILs over IR64-SPIKE allele carrying alleles was due to increased number of filled grains/panicle. More than three times higher abundance of SPIKE transcripts was observed in Bhutmuri and NILs carrying this allele compared with IR64 and its allele carrying NILs. Higher rate of photosynthesis at more than 900 μmolm-2s-1 light intensity and more than six small vascular bundles between the two large vascular bundles in the flag leaves of Bhutmuri and its allele carrying NILs were also observed. The identified SPIKE allele and the marker associated with it will be useful for increasing the productivity of rice by marker-assisted breeding.

Microstructure evidence of rice lodging resistance based on quantitative X‐ray microtomography

AbstractEven though lodging seriously affects the growth and development of rice (Oryza sativa L.) little is known about the stem and root microstructural characteristics of lodging resistant and non‐lodging resistant rice. In this study, one lodging resistant rice variety lingliangyou238 (R1), and two non‐lodging resistant rice varieties, luliangyou996 (S1) and zhuliangyou819 (S2), were used to conduct synchrotron‐based X‐ray micro‐computed tomography. We found that the lodging resistant rice variety R1 had a third internode (N3) length that was reduced by 37.4% compared to S1. Meanwhile, the area of stem cross section, area of the medullary cavity, and the number of large and small vascular bundles in the N3 of R1 increased by 73.56, 73.10, 18.55, and 17.74%, respectively, compared to S2. In the 3D structure, there are many pore structures in the inner wall of the rice stalk. Quantitative analysis showed that the ratio of length/width of the pores of R1 was lower than S1 and S2. In the fourth internode, the volume and surface area of the large vascular bundle vessel of R1 was greater than S1 and S2. In the root system, we found that R1 had more cortical cells, and its length/width value was lower than S1 and S2. Our findings implied that besides the 2D level, more 3D information is needed to reveal the relationship between lodging and the spatial structure of the crop.

Effects of Nitrogen Forms and Application Rates on Nitrogen Uptake, Photosynthetic Characteristics and Yield of Double-Cropping Rice in South China

Nitrogen is an important element that affects the growth and yield of rice obviously. To explore the effects of nitrogen (N) on the growth of double-cropping rice, four consecutive trials were conducted in South China Agricultural University. Four N forms and five N application rates were set up. Rice N uptake, leaf anatomic structure, leaf fluorescence parameters and yield were studied. The results showed that rice leaf SPAD value and N content with urea treatment were the highest among 4 N forms at the heading and flowering stage. The order of rice yield and N use efficiency treated with different N forms were urea > ammonium sulfate > ammonium nitrate > sodium nitrate. The N application rate test showed that photochemical quantum efficiency and chemical quenching coefficient of rice leaves showed an inverted-V-type changing tendency with the highest value at 180 kg/hm2 N treatment. Treatment with less than 180 kg/hm2 N decreased the area and perimeter of small vascular bundles of the lateral leaves. Yield of early rice and later rice with 180 kg/hm2 urea treatment was 17.42 to 33.28% and 6.17 to 21.28% higher than those of other N levels, respectively. The above results suggested that 180 kg/hm2 of urea N are suitable and recommended for double-cropping rice planting in South China.

Nitrogen Supply Regulates Vascular Bundle Structure and Matter Transport Characteristics of Spring Maize Under High Plant Density.

Nitrogen (N) fertilizer application greatly enhances grain yield by improving dry matter accumulation and grain filling in spring maize. However, how N application rates regulate the vascular bundle structure, matter transport and grain filling of spring maize under a high planting density has been poorly understood thus far. In this study, we analyzed the relationship between grain filling, vascular bundle structure and matter transport efficiency (MTE) of spring maize in the field. Zhongdan909 (ZD909) was used as the experimental material in a 2-year field experiment from 2015 to 2016, and it was grown under different N levels (0, 150, and 300 kg N ha–1) applied to the grain-filling stage of plots with planting densities of 67,500 plants ha–1 (ND) and 90,000 plants ha–1 (HD). Nitrogen application significantly optimized the structure of the big and small vascular bundles. In particular, there was an increase in the total number of small vascular bundles in the peduncle and cob of the ear system, i.e., increases of 51.8% and 25.7%, respectively, and the proportions of small vascular bundles to the total number of vascular bundles in the peduncle and cob were significantly increased. The root bleeding sap and MTE of maize were significantly increased by N application under both ND and HD, as indicated by the significant increase in the rate of 13C-photosynthate allocation to grain and amount of postsilking dry matter at maturity. Moreover, N application greatly improved the mean grain-filling rate (Gmean) under ND and HD by 30.0% and 36.1%, respectively, and the grain-filling rate increased, leading to a distinct improvement in the grain sink at the grain-filling stage. We concluded that nitrogen application significantly optimized the vascular bundle structure of the ear system, increased the MTE and improved photosynthate distribution to the grain, ultimately enhancing the filling rate and grain yield.

Coleataenia prionitis, a C4-like species in the Poaceae.

C4-like plants represent the penultimate stage of evolution from C3 to C4 plants. Although Coleataenia prionitis (formerly Panicum prionitis) has been described as a C4 plant, its leaf anatomy and gas exchange traits suggest that it may be a C4-like plant. Here, we reexamined the leaf structure and biochemical and physiological traits of photosynthesis in this grass. The large vascular bundles were surrounded by two layers of bundle sheath (BS): a colorless outer BS and a chloroplast-rich inner BS. Small vascular bundles, which generally had a single BS layer with various vascular structures, also occurred throughout the mesophyll together with BS cells not associated with vascular tissue. The mesophyll cells did not show a radial arrangement typical of Kranz anatomy. These features suggest that the leaf anatomy of C. prionitis is on the evolutionary pathway to a complete C4 Kranz type. Phosphoenolpyruvate carboxylase (PEPC) and pyruvate, Pi dikinase occurred in the mesophyll and outer BS. Glycine decarboxylase was confined to the inner BS. Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) accumulated in the mesophyll and both BSs. C. prionitis had biochemical traits of NADP-malic enzyme type, whereas its gas exchange traits were close to those of C4-like intermediate plants rather than C4 plants. A gas exchange study with a PEPC inhibitor suggested that Rubisco in the mesophyll could fix atmospheric CO2. These data demonstrate that C. prionitis is not a true C4 plant but should be considered as a C4-like plant.

Anatomical traits of Artemisia umbelliformis subsp. eriantha (asteraceae) alpine glacial relict from Mt. Durmitor (Montenegro)

In this study, the vegetative anatomy of Artemisia umbelliformis subsp. eriantha, a Central European alpine glacial relict, wild-growing on Mt. Durmitor (Montenegro) was examined for the first time. The aim was to investigate the general anatomy and particular anatomical traits which might have possible taxonomic value. Microscopic slides were prepared according to the standard histological procedures. The adventitious young root showed a primary structure, while the older root showed a secondary structure with a well-developed periderm on its surface. The rhizome showed a primary structure with elements of a secondary structure (periderm). The stem cross section is characterized by a round shape with a well-developed periderm at certain stages, and collateral vascular bundles arranged in a circle. The petiole is concave in shape with a single-layered epidermis and parenchyma tissue with one large and two small vascular bundles. Druses and rhombohedral crystals are observed inside some petiole parenchyma cells. The leaf lobe cross section has an oblong-linear shape and is isolateral and amphistomatous in structure. The anticlinal walls of the leaf epidermal cells are sinuate. Secretory canals are present in the root cortex parenchyma (endodermal secretory canals) and the rhizome cortical parenchyma. The stem, petiole and leaf lack secretory canals. The stem and leaf are covered with T-shaped non-glandular and glandular trichomes. The taxonomic value of the analyzed characteristics is briefly discussed.

Combination Effect Between Lead and Salinity on Anatomical Structure of Date Palm Phoenix dactylifera L. Seedlings

The study was conducted to evaluate the effect of lead (Pb) stress alone or in combination with salinity on the anatomical structure of roots and leaves of Date palm seedlings. Pb was added to soil at 100, 300 and 600 mg/kg concentrations as a pure aqueous solution or mixed with saline solution at 200 mM. Compared with the control, the microscopic study of root tissues showed that all treatments caused a significant increase in the thickness of epidermis, endodermis and pericycle, whereas the cortex thickness and diameters of the vascular cylinder, protoxylem and metaxylem decreased significantly. However, only the phloem diameter was affected significantly by 600 mg/kg Pb with or without salinity. Compared with the control, results on leaf tissues revealed that treatment with 300 and 600 mg/kg Pb alone or in combination with salinity led to a significant increase in the thickness of cuticle layer, upper epidermis and lower epidermis. Results also showed a significant increase in the diameter of tannin and palisade cells when treated with 100 mg/kg Pb with or without salinity. Small vascular bundle diameter decreased significantly in seedlings exposed to Pb at all examined concentrations with or without salinity.

Physiological characters and gene mapping of a dwarf and wide-leaf mutant <italic>osdwl1</italic> in rice (Oryza sativa L.)

<p indent=0mm>Plant height is one of the important factors affecting rice lodging. The semi-dwarf rice varieties possess high level of lodging resistance, and could reduce yield loss and improve grain quality. Thus, it is very important to study the molecular and physiological mechanism of dwarf formation in rice. In this study, a stable hereditary dwarf and wider-leaf mutant <italic>osdwl1</italic> was obtained from ⁶⁰Co γ-radiated <italic>indica</italic> restore line Zixuan 1, and its morphological and physiological characteristics, cytological observation, genetic analysis and gene mapping were investigated. Under field condition, the mutant <italic>osdwl1</italic> exhibited dwarf and wider-leaf after the tillering stage due to shorter length of the parenchyma cells, and its panicle length and all internodes length were significantly shorter compared with wild type plants at mature stage. Paraffin sections and scanning electronic microscopy (SEM) observation revealed that the number of small vascular (SV) bundles and the distance between SVs increased significantly, resulting in wider-leaf blade in <italic>osdwl1</italic>. Moreover, the number of microhairs on the abaxial and adaxial epidermis were also increased significantly in <italic>osdwl1</italic>. In addition, starting at the 3–4 leaf seedling stage, yellowing was visible at the upper middle parts of old leaves in <italic>osdwl1</italic>. Physiological analysis and transmission electron microscopy (TEM) observation indicated that the lamellar structure of chloroplast was distorted and began to collapse in some mesophyll cells, which led to the reduction of total chlorophyll contents, net photosynthetic rate and <italic>F</italic>_v/<italic>F</italic>_m ratio of the second and third leaves from top in <italic>osdwl1</italic> at the heading stage. Relative to the wild type plants, the soluble protein content, catalase (CAT) and superoxide dismutase (SOD) activities were significantly decreased, which in turn resulting in the accumulation of H₂O₂ and O₂^܋, and a steady increase of malondialdehyde (MDA) contents in the mutant leaves. Genetic analysis and gene mapping showed that <italic>osdwl1</italic> was controlled by a single recessive nuclear gene, located in a region of 333 kb between SSR marker RM19297 and the InDel marker ID269-2 on the short arm of chromosome 6. The results would further facilitate the cloning and functional analysis of <italic>OsDWL1</italic> gene.

Anatomical Characteristics of Leaves and Flowers of Cornus sanguine subsp. australis (C.A.Mey.) Jav.

Introduction: Cornus sanguinea subsp. australis (C.A.Mey.) Jav. is a widespread plant of the Caucasus (Russia). This is a small decorative tree with a large mass of raw material of leaves and flowers, which contain phenolic compounds. Currently, this plant is used in traditional medicine in some countries. Materials and Methods: C. australis leaves, and flowers were collected during the flowering period on the Mount Mashuk in Pyatigorsk, Stavropol region, Russia in June 2019. The anatomical structure of C. australis is considered in accordance with the requirements of the State Pharmacopoeia XIV. Results: There are heavily sinuous walls of cells of the upper and lower epidermis in microscopy of the leaves of C. australis, stomatal anomocytic type, Т-shaped trichomes, two types of mesophyll: palisade and spongy. In the vascular system of the leaf and petiole, there are two vascular bundles: small and larger. In the small vascular bundle, the xylem is located from the abaxial surface, the phloem – from the adaxial surface, in the big vascular bundle on the contrary. The lower epidermis of the petal and sepal is covered with T-shaped trichomes. Conclusion: Obtained anatomical signs are necessary for identification, authenticity, standardization for the use of C. australis as raw materials for pharmaceutical purposes.

Physiological and Anatomical Mechanisms in Wheat to Cope with Salt Stress Induced by Seawater.

Two pot experiments were conducted in a greenhouse to examine 14C fixation and its distribution in biochemical leaf components, as well as the physiological and anatomical adaptability responses of wheat (Triticum aestivum L.) grown with seawater diluted to 0.2, 3.0, 6.0, and 12.0 dS m−1. The results showed significant reductions in chlorophyll content, 14C fixation (photosynthesis), plant height, main stem diameter, total leaf area per plant, and total dry weight at 3.0, 6.0, and 12.0 dS m−1 seawater salt stress. The 14C loss was very high at 12.0 ds m−1 after 120 h. 14C in lipids (ether extract) showed significant changes at 12.0 dS m−1 at 96 and 120 h. The findings indicated the leaf and stem anatomical feature change of wheat plants resulting from adaptation to salinity stress. A reduction in the anatomical traits of stem and leaf diameter, wall thickness, diameter of the hollow pith cavity, total number of vascular bundles, number of large and small vascular bundles, bundle length and width, thickness of phloem tissue, and diameter of the metaxylem vessel of wheat plants was found. In conclusion, salt stress induces both anatomical and physiological changes in the stem and leaf cells of wheat, as well as the tissues and organs, and these changes in turn make it possible for the plants to adapt successfully to a saline environment.