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Cenchrus ciliaris is a potential forage grass that is widely distributed in saline desert condition across Africa, Australia and Asia. To examine anatomical characteristics relating to ionic and nutritional contents in response to salinity, Cenchrus ciliaris populations from the naturally salt-affected region of the Cholistan Desert, Pakistan were collected. The experiment was planned in a completely randomized design (CRD) with four replications and four treatment levels (0, 100, 200, and 300 mM NaCl) in a hydroponic system. After six months of growth in nutrient solution anatomical characteristics relating to ionic and nutritional traits were studied. It was hypothesized that C. ciliaris at higher salt stress must have developed some specific structural adaptations, which are responsible for better survival under high salt stress. At root level, C. ciliaris showed decreased root thickness with greater proportion of parenchyma cells in cortical region and increased sclerification in cortex and pith regions at high salinity levels, which are vital for water conservation under osmotic stress. At stem level increased stem area, cortical and vascular bundle cell area were recorded with increase in salinity level of external growth medium. Salt tolerance in C. ciliaris mainly associated with restricted uptake of toxic Na+ and Cl− ions at roots, accompanied by increased concentration of K+ and Ca++ in shoot. Under high salinities, C. ciliaris showed increased epidermis thickness, well developed bulliform cells, and increased trichome density at leaf level. All these structural modification in this species may contribute towards water conservations under physiological stress that is caused by high level of soil salinity. Various nutritional traits such as crude protein, ash content, relative feed value, and net energy of lactation slightly improved with salinity. Present study revealed nutritional potential, ionic contents and anatomical adaptations of C. ciliaris to cope with salinity. As such this species can be used to produce valuable fodder under saline desert environment.

The 2OG-Fe(II) oxygenase (RF) family of enzyme proteins can affect bulliform cells and cause leaf curling. However, there are few studies related to this family in cotton, and there has been no systematic analysis of RF genes. Here, we determined 25 RF genes in the complete genome sequence of upland cotton (Gossypium hirsutum L.) and 11 RF genes in the complete genome sequence of Arabidopsis thaliana. Cotton RF proteins can be divided into three categories. Whole genome/fragment and scattered replication events played an important role in the expansion of the RF gene family. qRT-PCR analysis results showed that RF genes respond to drought stress Pairwise comparison results showed that the expression of RF genes in Shi yuan 321 was higher than that in Kui 85–174. Overall, genome-wide identification approach was used to further analyze the related functions of the RF gene family, which may include the response to drought stress, in cotton.

SRL1 (SEMI-ROLLED LEAF 1) also named as CLD1 (CURLED LEAF AND DWARF 1), encoding a putative glycosylphosphatidylinositol-anchored membrane protein, has been characterized as a gene involved in the regulation of leaf morphology in rice. Mutants of srl1-1 (point mutation) and srl1-2 (transferred DNA insertion) exhibit defects in leaf development resulting in a phenotype with adaxially rolled leaves. To explore the gene regulatory network of leaf development controlled by SRL1 in rice, we created a homozygous SRL1 knock out (KO) line by CRISPR/Cas9, which showed defects in leaf development with adaxially rolling. By comparing the leaf transcriptome of a homozygous SRL1 KO line (srl1-KO) with the control, a total number of 3178 genes were identified as differentially expressed genes, of which 1,216 genes were significantly upregulated, while 1962 genes were downregulated. Further analysis indicated that a group of differentially expressed genes that related to the bulliform cells development (OsZHD1, OsLBD3-7, RFS and ACL1) and the cuticle of leaves (CFL1) may take responsibility for the defects in leaf development for the srl1-KO. Moreover, the downregulation of cellulose synthase (CESA) genes and phenylalanine ammonia-lyase (PAL)/ cinnamoyl-CoA reductase (CCR) gene expressions may lead to the reduction of cellulose/lignin contents in srl1-KO. Our study sheds light on the gene regulatory network controlled by SRL1, the important leaf development-related gene, which could be utilized in future breeding.

PePIP2;7, a leaf-specific aquaporin gene in bamboo, is upregulated under abiotic stresses. Overexpressing PePIP2;7 confers abiotic stresses tolerance in transgenic Arabidopsis plant and yeast. Aquaporins (AQPs) participate in the regulation of water balance in plants. However, the function of AQPs in bamboo remains unclear. Here, PePIP2;7 was identified as a leaf-specific aquaporin gene in moso bamboo based on the expression analysis of transcriptome data and PCR. In situ hybridization further indicated that PePIP2;7 was mainly expressed in mesophyll cells of mature leaves, while in immature leaves it was dominant in blade edge cells followed by mesophyll cells. Interestingly, PePIP2;7 was strongly expressed in the mesophyll cells near bulliform cells of immature leaves, suggesting that PePIP2;7 might function in water transport and contribute to leaf unfolding. The transient expression assay showed that PePIP2;7 was a plasma membrane intrinsic protein. Furthermore, PePIP2;7 was upregulated under abiotic stresses such as high light, drought, and NaCl. Compared with Col-0, transgenic Arabidopsis plants overexpressing PePIP2;7 had better seed germination rate, longer taproot length, higher SOD activity, and lower MDA content under abiotic stresses. Besides, yeasts expressing PePIP2;7 also had higher tolerance to stress compared to the control. Taken together, our results show that PePIP2;7 is leaf-specific and involved in stress response, which provides new insights into aquaporin function in bamboo.

Silicon (Si) is a beneficial element for plants, the accumulation of which in plant cell walls prevents water loss through transpiration, which may represent an adaptive strategy for coping with drought stress. Future climate change scenarios predict that drought will become an increasingly important stress factor affecting crop productivity. This problem will be exacerbated by the tendency to irrigate crops with excessive amounts of water, a practice that is both environmentally and economically unsustainable. In this study, we aimed to evaluate the agronomic, physiological, and metabolic aspects of Si translocation in corn crops subjected to drought conditions and excess irrigation. The study was organized in a completely randomized factorial scheme, with five concentrations of applied Si and five levels of irrigation. The findings of the study indicated that the application of Si increased plant growth, stomatal density, and bulliform cell diameter, which provide a better balance in water use and photosynthesis, thereby favoring greater Si translocation and, consequently, an increase in the grain production of corn plants. Furthermore, we found that the application of water to the soil equivalent to 130% and 160% of the recommended level (excess water stress) does not increase plant metabolism or grain production, but does increase water consumption and production costs.

An ideal leaf shape is beneficial to the yield of rice. Molecular understanding of the leaf primordia and polarity establishment plays a significant role in exploring the genetic regulatory network of leaf morphogenesis. In recent years, researchers have cloned an array of coding genes and a few non-coding small RNAs involved in rice leaf development through regulating the development of leaf primordia, vascular bundles, sclerenchyma cells, bulliform cells, cell walls and epidermis cells. These genes and their interactions play critical roles in rice leaf development through the determination and regulatory role in gene expression, and their coordination with other genetic networks or signal pathways. But the relationship among these genes is poorly defined and the underlying network is still unclear. In this review, we introduced the regulatory pathways of leaf primordium development and leaf polarity establishment, mainly the relationship between cell development mechanism and leaf polarity establishment, focusing on how leaf tissue affects leaf shape. Hopefully, the regulation network reviewed here has immediate implications for future research and genomic design breeding.

Background and Aims Andropogon gerardii is a highly productive C4 grass species with a large geographic range throughout the North American Great Plains, a biome characterized by a variable temperate climate. Plant traits are often invoked to explain growth rates and competitive abilities within broad climate gradients. For example, plant competition models typically predict that species with large geographic ranges benefit from variation in traits underlying high growth potential. Here, we examined the relationship between climate variability and leaf-level traits in A. gerardii, emphasizing how leaf-level microanatomical traits serve as a mechanism that may underlie variation in commonly measured traits, such as specific leaf area (SLA). Methods Andropogon gerardii leaves were collected in August 2017 from Cedar Creek Ecosystem Science Reserve (MN), Konza Prairie Biological Station (KS), Platte River Prairie (NE) and Rocky Mountain Research Station (SD). Leaves from ten individuals from each site were trimmed, stained and prepared for fluorescent confocal microscopy to analyse internal leaf anatomy. Leaf microanatomical data were compared with historical and growing season climate data extracted from PRISM spatial climate models. Key Results Microanatomical traits displayed large variation within and across sites. According to AICc (Akaike’s information criterion adjusted for small sample sizes) selection scores, the interaction of mean precipitation and temperature for the 2017 growing season was the best predictor of variability for the anatomical and morphological traits measured here. Mesophyll area and bundle sheath thickness were directly correlated with mean temperature (annual and growing season). Tissues related to water-use strategies, such as bulliform cell and xylem area, were significantly correlated with one another. Conclusions The results indicate that (1) microanatomical trait variation exists within this broadly distributed grass species, (2) microanatomical trait variability appears likely to impact leaf-level carbon and water use strategies, and (3) microanatomical trait values vary across climate gradients, and may underlie variation in traits measured at larger ecological scales.

The morphology of bulliform cells located on the upper epidermis of leaves is one of the most important cell structures affecting leaf shape. Although many mechanisms regulating the development of bulliform cells have been reported, the fine regulatory mechanisms governing this process have rarely been described. To identify novel components regulating rice leaf morphology, a mutant showing a constitutively rolling phenotype from the seedling stage to flowering, known as crm1‐D, was selected for further analysis. Anatomical analyses in crm1‐D were attributable to the size reduction of bulliform cells. The crm1‐D was controlled by a single dominant nuclear gene. Map‐based cloning revealed that Roc8, an HD zipper class IV family member, was responsible for the crm1‐D phenotype. Notably, the 50‐bp sequence in the 3′‐untranslated region (3′‐UTR) of the Roc8 gene represses Roc8 at the translational level. Moreover, the roc8 knockdown lines notably increased the size of bulliform cells. A series of assays revealed that Roc8 negatively regulates the size of bulliform cells. Unexpectedly, Roc8 was also observed to positively mediate lignin biosynthesis without incurring a production penalty. The above results show that Roc8 may have a practical application in cultivating materials with high photosynthetic efficiency and low lignin content.

SUMMARY The Elongator complex, which is conserved in eukaryotes, has multiple roles in diverse organisms. In Arabidopsis thaliana, Elongator is shown to be involved in development, hormone action and environmental responses. However, except for Arabidopsis, our knowledge of its function is poor in plants. In this study, we initially carried out a genetic analysis to characterize a rice mutant with narrow and curled leaves, termed curled later1 (cur1). The cur1 mutant displayed a heteroblastic change, whereby the mutant leaf phenotype appeared specifically at a later adult phase of vegetative development. The shoot apical meristem (SAM) was small and the leaf initiation rate was low, suggesting that the activity of the SAM seemed to be partially reduced in cur1. We then revealed that CUR1 encodes a yeast ELP1‐like protein, the largest subunit of Elongator. Furthermore, disruption of OsELP3 encoding the catalytic subunit of Elongator resulted in phenotypes similar to those of cur1, including the timing of the appearance of mutant phenotypes. Thus, Elongator activity seems to be specifically required for leaf development at the late vegetative phase. Transcriptome analysis showed that genes involved in protein quality control were highly upregulated in the cur1 shoot apex at the later vegetative phase, suggesting the restoration of impaired proteins probably produced by partial defects in translational control due to the loss of function of Elongator. The differences in the mutant phenotype and gene expression profile between CUR1 and its Arabidopsis ortholog suggest that Elongator has evolved to play a unique role in rice development., Significance Statement We revealed that genes encoding the subunit of Elongator complex play an important role in the differentiation of bulliform and sclerenchyma cells in leaf development and in the maintenance of the shoot apical meristem. The mutant leaf phenotypes appeared specifically at the late adult phase of the vegetative development, suggesting a unique role of the Elongator complex in rice.

The archaeological sites of Shunshanji and Hanjing are recorded as the earliest Neolithic sites in the middle Huai river valley, China, which were occupied between 8,500 and 7,500 cal bp, and provide crucial evidence of rice growing. However, the water availability and management of arable land systems for rice cultivation and the main stages of rice processing at the two sites have not been studied before. In this paper, phytolith analyses are discussed in 66 samples from the Shunshanji site and 32 samples from the Hanjing site, with three phases of occupation at each. The ratios of sensitive to fixed forms in the phytolith assemblages over three phases reveal that in Phase I these ratios are relatively low, and they become significantly higher in Phases II and III at both sites. These results suggest that rice was grown probably only using natural water supplies in the lowlands during Phase I, but changed to growing on highly controlled and regularly flooded and drained wetlands in Phase II at the two sites. In addition, seen from the distribution and concentrations of phytoliths from rice, weeds and their by-products, as well as the proportions of each, both double peaked glume cells (DPG) and rice cuneiform bulliform cells (RCB) were found together with some rice paddy weed phytoliths. The concentrations of DPG were much higher than those of RCB in most samples from the Shunshanji and Hanjing sites over the three phases. The findings imply that rice ears together with the stems and leaves were probably stored after the harvest, then threshed and de-husked simultaneously, and the straw and chaff by-products were discarded together at the sites between 8,500 and 7,500 cal bp. The study in this paper aims towards a better understanding of past human behaviour and social organization in rice growing communities during the middle Neolithic in eastern China.

The leaf anatomy, photosynthetic system parameters and accumulation of carbohydrates were determined at different times for Bipolaris oryzae pathogenesis in two rice cultivars (BRS Querencia and Inov CL), grown in an environment with 400 ppm or 700 ppm of atmospheric CO2. The results demonstrated that the plants exposed to 700 ppm underwent changes in anatomical characteristics (reduction in parenchyma thickness and size of bulliform cells), photosynthetic parameters (increased carbon assimilation rate, leaf intercellular CO2 concentration and water use efficiency, and reduction of stomatal conductance to water vapor, transpiration rate and carboxylation efficiency), and carbohydrate accumulation (increased concentration of soluble sugars and starch), when compared to plants at 400 ppm. Therefore, the changes in morphological traits of the leaf and the accumulation of carbohydrates, which were stimulated in the rice plants by increased CO2 concentration (700 ppm), were associated with less severe brown spot, caused by B. oryzae.

Sugarcane is a very important crop in tropical areas around the world. Optimizing the light intensity and culture vessel for sugarcane in vitro propagation can improve protocols for large-scale in vitro mass clonal propagation. The objective of this study was to evaluate biometric and anatomical characteristics of in vitro propagated sugarcane plantlets using different light intensities and culture vessel types. The study also aimed to stimulate desired photoautotrophic and/or photomixotrophic traits and to study correlations between survival and ex vitro vigor with in vitro data. Fluorescent lights at 70 μmol m−2 s−1 and light-emitting diodes (LEDs) at 120 and 200 μmol m−2 s−1 were used combined with different culture vessel types, including microboxes without a filter, microboxes with a filter, and baby food jars. Propagation and rooting growth were observed in all in vitro culture conditions. However, an increase in light intensity and change of culture vessel type provided improved results. When sugarcane plantlets were cultivated within microboxes with a filter under 120 and 200 μmol m−2 s−1, they showed improved growth, increased chlorophyll content, the lowest leaf yellowing percentage, an increase in bulliform cells and, consequently, increased leaf thickness under in vitro culture. After 60 d in greenhouse conditions, in vitro-derived plantlets under LEDs and microbox culture vessels showed the highest biometric values and high ex vitro survival.

Corolla closure protects pollen from high-temperature stress during pollen germination and fertilization in the ornamental plant morning glory (Ipomoea purpurea). However, the morphological nature of this process and the molecular events underpinning it remain largely unclear. Here, we examined the cellular and gene expression changes that occur during corolla closure in the I. purpurea. We divided the corolla closure process into eight stages (S0–S7) based on corolla morphology. During flower opening, bulliform cells appear papillate, with pigments in the adaxial epidermis of the corolla. These cells have distinct morphology from the smaller, flat cells in the abaxial epidermis in the corolla limb and intermediate of the corolla. During corolla closure, the bulliform cells of the adaxial epidermis severely collapse compared to cells on the abaxial side. Analysis of transparent tissue and cross sections revealed that acuminate veins in the corolla are composed of spiral vessels that begin to curve during corolla closure. When the acuminate veins were compromised, the corolla failed to close normally. We performed transcriptome analysis to obtain a time-course profile of gene expression during the process from the open corolla stage (S0) to semi-closure (S3). Genes that were upregulated from S0 to S1 were enriched in the polysaccharide degradation pathway, which positively regulates cell wall reorganization. Senescence-related transcription factor genes were expressed beginning at S1, leading to the activation of downstream autophagy-related genes at S2. Genes associated with peroxisomes and ubiquitin-mediated proteolysis were upregulated at S3 to enhance reactive oxygen species scavenging and protein degradation. Therefore, bulliform cells and acuminate veins play essential roles in corolla closure. Our findings provide a global understanding of the gene regulatory processes that occur during corolla closure in I. purpurea.

In crops such as maize, the leaf is directly related to dry-matter accumulation in the grain, and directly affects plant yield. The aim of this study was to verify the existence of a correlation between the agronomic and anatomical characteristics of the maize leaf, as well as to verify the effects of these characteristics on grain production using path analysis. The agronomic characteristics used in the analysis were plant height, height of ear insertion, relative position of the ear, lodging, plant breakage and grain yield. The following anatomical characteristics were evaluated: total leaf area, thickness of the bulliform cells, thickness of the adaxial and abaxial epidermis, thickness of the mesophyll, area of the xylem, phloem and sclerenchyma, and mean area of the vascular bundles. In analysing the genotypic correlation, associations were seen at 1% significance between mesophyll thickness and plant height, mesophyll thickness and height of ear insertion, and mesophyll thickness and plant breakage, indicating the possibility of indirect selection for these agronomic characteristics. From the path analysis, it was found that the agronomic characteristics of lodging and breakage, and the anatomical characteristics of thickness of the adaxial epidermis, area of the xylem and area of the sclerenchyma had the greatest direct effect on grain yield, indicating the additional possibility of indirect selection for yield during the earliest stages of the plant. These results can afford faster selection of superior genotypes within the various breeding programs of the species. RESUMO Em culturas como o milho, a folha está diretamente relacionada ao acúmulo de matéria seca nos grãos, interferindo assim diretamente na produção da planta. Objetivou-se no presente trabalho verificar a existência de correlação entre caracteres agronômicos e anatômicos da folha em milho, bem como verificar os efeitos desses caracteres na produção de grãos pela análise de trilhas. Os caracteres agronômicos utilizados para análise foram: altura da planta, altura de inserção da espiga, posição relativa da espiga, acamamento, quebramento de planta e produtividade de grãos. Os caracteres anatômicos avaliados foram: área total da folha, espessura das células buliformes, espessura da epiderme adaxial, espessura da epiderme abaxial, espessura do mesofilo, área do xilema, área do floema, área do esclerênquima e área média dos feixes vasculares. Na análise da correlação genotípica foram observadas associações a 1% de significância entre os caracteres espessura do mesofilo e altura de plantas, espessura do mesofilo e altura de inserção da espiga, e espessura do mesofilo e quebramento de planta, indicando a possibilidade de seleção indireta para tais caracteres agronômicos. Na análise de trilha observou-se que os caracteres agronômicos: acamamento e quebramento, e anatômicos: espessura da epiderme adaxial, área do xilema e área do esclerênquima foram os que apresentaram maior efeito direto sobre a produção de grãos em milho, indicando a possibilidade de seleção indireta também para o rendimento nos estágios mais precoces da planta. Tais resultados podem proporcionar maior rapidez na seleção de genótipos superiores dentro dos diferentes programas de melhoramento da espécie.

Key message Elevated expression of nucleotide-binding and leucine-rich repeat proteins led to closer vein spacing and higher vein density in rice leaves. Abstract To feed the growing global population and mitigate the negative effects of climate change, there is a need to improve the photosynthetic capacity and efficiency of major crops such as rice to enhance grain yield potential. Alterations in internal leaf morphology and cellular architecture are needed to underpin some of these improvements. One of the targets is to generate a “Kranz-like” anatomy in leaves that includes decreased interveinal spacing close to that in C4 plant species. As C4 photosynthesis has evolved from C3 photosynthesis independently in multiple lineages, the genes required to facilitate C4 may already be present in the rice genome. The Taiwan Rice Insertional Mutants (TRIM) population offers the advantage of gain-of-function phenotype trapping, which accelerates the identification of rice gene function. In the present study, we screened the TRIM population to determine the extent to which genetic plasticity can alter vein density (VD) in rice. Close vein spacing mutant 1 (CVS1), identified from a VD screening of approximately 17,000 TRIM lines, conferred heritable high leaf VD. Increased vein number in CVS1 was confirmed to be associated with activated expression of two nucleotide-binding and leucine-rich repeat (NB-LRR) proteins. Overexpression of the two NB-LRR genes individually in rice recapitulates the high VD phenotype, due mainly to reduced interveinal mesophyll cell (M cell) number, length, bulliform cell size and thus interveinal distance. Our studies demonstrate that the trait of high VD in rice can be achieved by elevated expression of NB-LRR proteins limited to no yield penalty.

Cenchrus ciliaris L. is a widely used species for cattle feed in arid and semi-arid regions due to good forage value and known tolerance to drought conditions. Here, we provide insights to adaptive responses of two contrasting genotypes of C. ciliaris (drought-tolerant “RN51” and drought-sensitive “RN1”) to face drought stress and recovery conditions and the implications for tissue lignification. Drought stress caused a reversible decrease in the leaf water relationship and damage to photosystem II, leading to an increased generation of reactive oxygen species and lipid peroxidation. Plants of RN51 exhibited a pronounced increase of antioxidant enzymatic activities. Unlike the drought-sensitive genotype, RN51 exhibited further development of lignified tissues and bulliform cells and had the greatest thickness of the adaxial epidermis. Drought stress led to the rapid activation of the expression of lignin biosynthesis pathway-related enzymes. The transcript level of the caffeoyl-CoA O-methyltransferase gene decreased in RN1, whereas cinnamoyl-CoA reductase transcripts were increased in RN51. After rewatering, the tolerant genotype recovered more rapidly than RN1. Even though the two genotypes survived when they were exposed to drought stress, RN1 showed the highest reduction in growth parameters, and this reduction was sustained during rewatering. The results indicated that the capacity to regulate lipid peroxidation and mitigate oxidative damage could be one of the mechanisms included in tolerance to drought stress. In addition, the development of foliar characteristics, like thickness of the adaxial epidermis, well-developed bulliform cells, and intensive lignified tissues, are considered anatomical adaptive strategies for drought tolerance in C. ciliaris. Fil: Carrizo, Iliana Magalí. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Estudios Agropecuarios - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Estudios Agropecuarios; Argentina Fil: Lopez Colomba, Eliana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Estudios Agropecuarios - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Estudios Agropecuarios; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Genéticos Vegetales; Argentina. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias; Argentina Fil: Tommasino, Exequiel Arturo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Genéticos Vegetales; Argentina Fil: Carloni, Edgardo José. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Genéticos Vegetales; Argentina Fil: Bollati, Graciela. Universidad Católica de Córdoba. Facultad de Ciencias Agropecuarias; Argentina Fil: Grunberg, Karina Alejandra. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Estudios Agropecuarios - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Estudios Agropecuarios; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Fisiología y Recursos Genéticos Vegetales; Argentina

Moderate curling of leaves helps to improve the photosynthetic efficiency, and increase the overall effective accumulation of photosynthate. We identified a stable mutant from the library constructed by treating indica maintainer line Xinong 1B with ethyl methane sulfonate (EMS). Leaves of the mutant gradually curled outwards into a semi-coiled shape, accompanied by semi-dwarfing of the culm and leaf drooping from the 10-leaf stage, the mutant was temporarily named as semi-outcurved leaf 1 ( sol1 ). The calculated leaf curl index of sol1 was 30%, statistically higher than that of wild type (WT, P sol1 were significantly or very significantly decreased, while primary branch number increased by 11.3%, statistically higher than that of WT ( P sol1 were significantly higher than those of wild type. The results of paraffin section showed that the bulliform cells of the Top1 of sol1 exhibited smaller, but their number increased significantly, and the volume of epidermal cells increased slightly. Genetic analysis indicated that sol1 was controlled by a recessive nuclear gene. SOL1 was precisely located in the physical distance of 165 kb between the markers of JY6-3 and JY6-10 on the short arm of chromosome 6, with 15 annotated genes. The results of qRT-PCR showed that RL14 , Roc5 , and REL1 related to bulliform cells were up- regulated in mutant sol1 , while NRL , BRD1 , OsHox32 , ADL1 , LC2 down-regulated. The results of the present study provide a basis for SOL1 cloning, and functional dissection as well.

Each organ plant has been formed perfectly to support physiological processes in an unfavorable environmental condition. Rice (Oryza sativa L.) be included plants sensitive to drought conditions during a stage of growth and development. This will cause pressure (stress) resulting in a decrease in rate metabolism in leaf cells. Leaf anatomical characteristics are criteria that can be used to identify plants that are tolerant to drought. Anatomical response leaves in drought conditions inform the development of leaf photosynthetic parts carrying out changes in anatomical structure morphology includes changes in cell walls, organ size, changes in direction growth, including dropping leaves and enhancing the life cycle. The research aimed to determine the anatomic response leaves rice varieties (Oryza sativa L.) to drought stress. Five rice varieties used were given drought-stress treatment for 12 days. Identification leaf anatomical structures using microscopic slices of transverse was made according to the paraffin method. Changes in the anatomical structure of leaves of drought-stress have decreased bulliform cells increase in size, the thickness epidermis cells in an effort to retain the water content in cells, and reducing the size and total stomata with purpose process control flow of transpiration and water use efficiency.

The aim of this work was to determine the anatomical adaptations of leaves and stems of four species of Poaceae (Cynodon dactylon L. Pers., Chloris barbata SW. (Chloridoideae), Setaria verticillata L. P. Beauv., and Panicum coloratum L. (Panicoideae)) growing naturally at Al-Ha'ir region near Riyadh, Saudi Arabia. Cross-sections of the leaves revealed that the epidermis cells were spherical to oval and formed one layer with a thick cuticle as well as numerous bulliform cells in a fan shape and prickles. Ground tissue (mesophyll) consists mostly of chlorenchyma cells. A large vascular bundle surrounded by two bundle sheaths, outer sheath parenchyma and inner sheath sclerenchyma were observed in C. barbata and C. dactylon, while one bundle sheath of sclerenchyma surrounds the vascular bundle in S. verticillata and P. coloratum, while one bundle sheath with chlorenchymatous cells surrounded the small vascular bundles. Our results showed that all species contained a Kranz anatomy indicative of a C4 photosynthetic pathway despite belonging to two different subfamilies, Panicoideae and Chloridoideae. Oil droplets appeared in the mesophyll tissue of P. coloratum and S. verticillata. Cross-sections of stems revealed an epidermis which consists of one layer of cells with spherical to oval shape and had a thick cuticle. Ground tissue contains strands of chlorenchyma cells followed by sclerenchyma tissue surrounding vascular bundles, thereby making a continuous cylinder. The vascular bundles were scattered in the ground tissue, with each vascular bundle surrounded by a single sclerenchymatous bundle sheath. Our results indicate that these plants were characterized by anatomical adaptations that enhance drought-tolerance capabilities, facilitating survival in arid and semi-arid regions such as Al-Ha'ir and thus these plants can be used to increase vegetation cover and pasture area in dry environments. Key words: Anatomy, adaptations, Poaceae, Cynodon dactylon, Chloris barbata, Setaria verticillata, Panicum coloratum.

Oat (Avena sativa) plants grown under 60% field capacity (water-deficit stress) were subjected to proline (40 mM) applied as a foliage spray. Water-deficit conditions suppressed plant growth, chlorophyll contents, leaf vascular bundle area, leaf phloem area and leaf midrib thickness, root diameter, root cortex thickness, stem diameter, stem vascular bundle area and stem phloem area. In contrast, water stress caused an increase in leaf proline, hydrogen peroxide, activities of peroxidase and superoxide dismutase enzymes, leaf bulliform cell area, leaf adaxial epidermis thickness, leaf sclerenchyma thickness, root metaxylem area, root epidermis and endodermis area, root stelar diameter, stem sclerenchyma thickness and stem epidermis thickness. However, exogenous application of proline significantly improved the plant growth, leaf proline contents, metaxylem area, mesophyll thickness, root diameter, root cortex thickness, root epidermis, endodermis thickness, stelar diameter, metaxylem area, stem diameter, stem vascular bundle area, stem epidermis area, stem phloem area and stem sclerenchyma thickness. Overall, foliar spray of proline was effective in improving drought stress tolerance which can be attributed to proline-induced significant modulations in physio-biochemical and anatomical features of oat plants.

Although exogenous application of glycinebetaine (GB) is widely reported to regulate a myriad of physio-biochemical attributes in plants under stressful environments including drought stress, there is little information available in the literature on how and up to what extent GB can induce changes in anatomical features in water starved plants. Thus, the present research work was conducted to assess the GB-induced changes in growth, physio-biochemical, and anatomical characteristics in two cultivars (CK-1 and F-411) of oat (Avena sativa L.) under limited water supply. After exposure to water stress, a considerable reduction was observed in plant growth in terms of lengths and weights of shoot and roots, leaf mesophyll thickness, leaf midrib thickness, root cortex thickness, root diameter, stem diameter, stem phloem area, and stem vascular bundle area in both oat cultivars. However, water stress resulted in a significant increase in leaf total phenolics, hydrogen peroxide (H2O2), ascorbic acid (AsA), GB contents, activities of enzymes (CAT, SOD and POD), total soluble proteins, leaf epidermis (abaxial and adaxial) thickness, bulliform cell area, sclerenchyma thickness, root endodermis and epidermis thickness, root metaxylem area, stem metaxylem area and stem sclerenchyma thickness in both oat cultivars. Foliar-applied 100 mM GB suppressed H2O2 contents, while improved growth attributes, free proline and GB contents, activity of SOD enzyme, leaf abaxial epidermis thickness, leaf bulliform cell area, leaf midrib thickness, leaf sclerenchyma thickness, root cortex thickness, root endodermis, epidermis thickness, root stele diameter, stem diameter, stem epidermis thickness, stem metaxylem area, and stem phloem and vascular bundle area in both oat cultivars. For both oat cultivars, CK-1 was superior to F-411 in leaf abaxial epidermis thickness, leaf mesophyll, leaf sclerenchyma, root metaxylem area, stem diameter, stem epidermis, sclerenchyma thickness, stem metaxylem area, and stem vascular bundle area. Overall, both oat cultivars showed inconsistent behavior to water stress and foliar-applied GB in terms of different physio-biochemical attributes, however, CK-1 was superior to F-411 in a number of anatomical features of leaf, root, and stem.

Aristida adscensionis L. is a widely distributed grass species that particularly invades Potohar region (arid/semi-arid conditions) of the country. Exploration of adaptive components in this grass in relation to altitudinal gradient is the first attempt. Plant samples were collected from 6 different altitudinal ranges, viz. 400, 600, 800, 1000, 1200 and 1400 m a.s.l. Morpho-anatomical and physiological features along altitudinal gradient varied significantly that showed phenotypic plasticity in this species to inhabit a variety of environmental conditions. Stomata at 400 m altitude were larger and rhomboid-shaped, which changed to narrowly elliptic at moderate elevations and circular at high elevations. Growth and biomass production were maximum at 800–1000 m a.s.l. along with most of the morpho-anatomical and physiological features like proportion of vascular tissue, nutrient uptake, and chlorophyll pigments. Xeromorphy was high in plants colonisng at 1200 m elevations, which was indicated by an intensive sclerification, increased amount of storage parenchyma, increased vascular bundle number, deeply grooved bulliform cells, and dense pubescence on adaxial leaf surface. Leaf succulence was the unique feature in plants inhabiting 1400 m elevation. Another prominent feature was the development of chlorenchyma inner to stem epidermis. All these features reflect the tolerance capacity of A. adsecnsionis against environmental adversaries like salinity, aridity and low temperatures of the Potohar region.

summary C-value determinations on nuclei of the adaxial epidermal bulliform cells of leaves of perennial (Lolium perenne) and Italian ryehgrass (Lolium multiflorum) show considerable levels of endopolyploidy. L. multiflorum has more endopolyploidy than L. perenne, and there is an environmental effect which reduces the level of endopolyploidy in L. multiflorum as the temperature is raised.

Moderate leaf rolling is considered optimal for the ideal plant type in rice (Oryza sativa L.), as it improves photosynthetic efficiency and, consequently, grain yield. Determining the genetic basis of leaf rolling via the identification of quantitative trait loci (QTLs) could facilitate the development of high-yielding varieties. In this study, we identified three stable rice QTLs, qARO1, qARO5, and qARO9, which control adaxial leaf rolling in a recombinant inbred line (RIL) population derived from a cross between Tong 88-7 (T887) and Milyang 23 (M23), using high-density SNP markers. These QTLs controlled the rolling phenotype of both the flag leaf (FL) and secondary leaf (SL), and different allelic combinations of these QTLs led to a wide variation in the degree of leaf rolling. Additive gene actions of qARO1 and qARO9 on leaf rolling were observed in a backcross population. In addition, qARO1 (markers: 01id4854718 and 01asp4916781) and qARO9 (markers: 09id19650402 and 09id19740436) were successfully fine-mapped to approximately 60- and 90-kb intervals on chromosomes 1 and 9, respectively. Histological analysis of near-isogenic lines (NILs) revealed that qARO1 influences leaf thickness across the small vein, and qARO9 affects leaf thickness in the entire leaf and bulliform cell area, thus leading to adaxial leaf rolling. The results of this study advance our understanding of the genetic and molecular bases of adaxial leaf rolling, and this information can be used for the development of rice varieties with the ideal plant type.

Summary Moderately rolled leaf is one of the target traits of the ideal plant architecture in rice breeding. Many genes, including homeodomain leucine zipper IV transcription factors ROC5 and ROC8, regulating rice leaf rolling have been cloned and functionally analysed. However, the molecular mechanism by which these genes modulate leaf‐rolling remains largely elusive. In this study, we demonstrated the transcription activation activity of both ROC8 and ROC5. Overexpressing ROC8 caused adaxially rolled leaves due to decreased number and size of bulliform cells, whereas knockout of ROC8 induced abaxially rolled leaves due to increased number and size of bulliform cells. ROC8 and ROC5 each could form homodimer, but ROC8 interacted preferably with ROC5 to forms a heterodimer. Importantly, we showed that the ROC8‐ROC5 heterodimer rather than the homodimer of ROC8 or ROC5 was functional as neither overexpressing ROC8 in the ROC5 mutant nor overexpressing ROC5 in the ROC8‐knockout line could rescue the mutant phenotype. This was further partially supported by the identification of a large number of common differentially expressed genes in single and double mutants of roc8 and roc5. ROC8 and ROC5 were functionally additive as the phenotype of abaxially rolled leaves was stronger in the roc5roc8 double mutant than in their single mutants. Our results provide evidence for the role of dimerization of ROC members in regulating leaf rolling of rice.