Stomatal Structure Research Articles

Effect of Colchicine and Bio-catharantin on the DNA Relative Content and Stomatal Structure of Black Rice (Oryza sativa L. var. Jeliteng)

<p>Black rice (<em>Oryza sativa</em> L. var. Jeliteng), known for its health benefits compared to white rice, faces challenges in productivity. Among varieties, this black rice is popular in Indonesia but shows low yield. Research on improving black rice through genetic manipulation with antimitotic substances is limited. Therefore, this study aims to compare the effects of colchicine and Bio-catharantin on the germination rate, DNA relative content, and stomatal structure of <em>O. sativa </em>L. var. Jeliteng. Seeds were treated with colchicine (0.1%, 0.2%, and 0.3%) and Bio-catharantin (0.1%, 0.2%, 0.3%, 0.4%, and 0.5%) at soaking durations of 12, 24, and 48 hours. Germination was assayed, ploidy was determined using flow cytometry, and stomatal traits, including size and density, were examined microscopically. The results showed that Bio-catharantin did not exhibit any toxic effects on germination rates, whereas colchicine reduced germination starting at 0.2% concentration. Both chemical agents modified the DNA relative content of Jeliteng black rice. Colchicine generally increased stomatal length and width while decreasing stomatal density, with significant changes at 0.3% concentration for 24 hours. Bio-catharantin also altered stomatal traits, enhancing length and width in most cases but significantly reducing density under certain conditions. Bio-catharantin emerged as a promising alternative to colchicine for inducing chromosomal mutations in plants, offering benefits in altered stomatal structures without the toxic effects on germination, compared to colchicine.</p>

Anatomic and Phytochemical Investigation of Herbal Tea Bags Sold as Lemon Balm (Melissa officinalis L.) in the Market

Melissa officinalis L., an ethnobotanically valuable plant, has been used for the treatment of several diseases since ancient times. However, different plants with the same name are sold instead of lemon balm in markets that sell herbal products in Turkey. For this purpose, 15 different brands of tea bags in crushed form, sold as lemon balm (Melissa officinalis L.) in markets, were analyzed. The total phenolic, flavonoid and antioxidant capacities of the hydroalcoholic extracts of these tea samples along with the stomatal structure were investigated. Additionally, chemical compositions and rosmarinic acid contents were determined by the high-performance thin layer chromatography method. Among the samples examined, S1, S2, S9 and S12 tea samples were found to meet the eligibility criteria. The leaves of these samples had diacytic stomata and the rosmarinic acid ratio in their phytochemical composition was over 2%. Furthermore, caffeic acid was detected in these samples.

Contribution of the alternative pathway on spring rejuvenation of alfalfa

Alfalfa often suffers from low temperature during spring rejuvenation, so it is important to improve the cold tolerance of alfalfa leaves for its smooth rejuvenation, and the alternative pathway (AP) could effectively improve the plant's tolerance. In this study, the contribution of AP on spring rejuvenation of alfalfa was investigated in Xinmu No.4 and Gannong No.5 with different fall dormancy levels. Though the protein and AP capacity were decreased during the rejuvenation, the ratio of AP/TP were increased in two alfalfa varieties, compared to those in alfalfa before overwintering. This indicated that AP had positive response to alfalfa rejuvenation. The limitation of AP significantly affected the leaf length, leaf width and growth rate of greening alfalfa, showing that AP played an important role in alfalfa rejuvenation. Inhibition of AP resulted in a significant decrease in Pn, Ci, Gs and stomatal structure deformity, suggestion that AP affected photosynthesis by influencing stomatal development during rejuvenation. AP reduces oxidative damage to PSII core protein repair in alfalfa leaves and optimizes photosynthesis by up-regulating NADP-MDH activity, decreasing the accumulation of excess reducing power in the chloroplasts, and by increasing SOD and POD activities and decreasing the accumulation of hydrogen peroxide. The higher proportion of AP keeps it more tolerant to low temperature for rejuvenation in Xinmu No.4 with a lower fall dormancy level.

Morphology, Reproductive Biology and Anatomy of the Foxtail Orchid, Rhynchostylis retusa (L.) Blume

Background: Rhynchostylis retusa (L.) Blume, commonly known as the fox-tail orchid, is a promising epiphytic native species for breeding programs. Its’ population is diminishing in the native habitat due to unscrupulous overexploitation and habitat destruction. Hence, conservation of this species attains prime importance. To achieve the foregoing task, phenotypic traits in relation to adaptation are to be elucidated. Methods: In the present investigation, the morphological characters were documented and the correlation between each trait was determined. Furthermore, the anatomy of leaves and roots was documented, as was the stomatal structure and distribution on the abaxile and adaxile surfaces of the leaves. Biometric features of floral characters and reproductive biology such as anthesis, stigma receptivity, pollen production per pollinium, pollen viability, pollination mechanisms, self and cross-compatibility; male sterility, etc. were studied and documented. Observations on capsule development, nature of seeds, seed viability, etc. were also determined. Result: The seed viability tests revealed that about 40% of the seeds are viable. The observations gathered during this investigation can be used to develop conservation, sustainable utilization and genetic improvement strategies for this crop.

Pristionchus seladoniae n. sp. (Diplogastridae) isolated from a eusocial soil-dwelling bee, Halictus (Seladonia) aerarius, in Nagano, Japan

Summary A new species of Pristionchus was isolated from a soil-dwelling bee, Halictus (Seladonia) aerarius, collected from Sugadaira, Nagano, Japan. The nematode was successfully cultured on nematode growth medium agar previously inoculated with the Escherichia coli strain OP50; however, it did not propagate well. Typologically, the new species is similar to other Pristionchus belonging to the maupasi, pacificus and lheritieri groups in the stomatal structure of stenostomatous form. However, the species is characterised by the relatively short, conical tail of the female and the arrangement of male genital papillae in which the second- and third-paired papillae are almost at the same level and one of these two are directed laterally. Phylogenetically, the nematode belongs to the maupasi group, the ‘American clade’ within the genus, and is separable from the other species in the group. Biologically, the species has several interesting characters: it is seemingly native to Japan, regardless of its phylogenetic group; it is in tight and specific phoretic association with a eusocial bee; it lacks a eurystomatous form (or this form occurs rarely) under cultured conditions; and it shows characteristic clumping behaviour on culture media. The new species is taxonomically described herein as Pristionchus seladoniae n. sp.

Effect of light and cytokinin on growth and curculin gene expression of Curculigo latifolia on in vitro culture.

Despite being valuable for producing a natural sweetener Curculin, Curculigo latifolia has a low growth and difficult to domestificate. So, to solve this problem, propagation on in vitro culture will be an alternative method to propagated this spesies under different cytokinins and light condition. Cytokinins and light has major role in organogenesis, growth and gene expression of many species. Thus, in this study, we aimed to improve the Curculigo latifolia growth on in vitro condition and expression of curculin gene by combining cytokinins addition and different light exposure. Four weeks seedlings were sub-cultured into medium (MS free hormone) containing 3 mg/L benzyladenine (BA) and various concentrations of meta-Topolin (mT) including 0.1 mg/L, 0.5 mg/L, and 5 mg/L. The cultures then incubated under different light types (red, blue, white LED lights and white fluorescence light) with 16-h light/ 18-h dark photoperiod for 14 weeks at 25 ± 2°C. Several parameters, including plant height, leaf number, chlorophyll contents, stomatal structure, and density and curculin expression, were observed every week. Unexpectedly, our results showed that C. latifolia growth displayed significant improvement when it was treated under white LED light without any additional cytokinins. In sum, white LED light further improves plantlets phenotype, such as plant height, leaf number, chlorophyll production, and stomatal number and structure, whereas, red LED light lead to a decreased phenotypes but increase the curculin gene expression.

Integrated Cytological, Physiological, and Transcriptome Analyses Provide Insight into the Albino Phenotype of Chinese Plum (Prunus salicina).

Albino seedlings that arise during seed reproduction can have a significant impact on plant growth and breeding. In this research, we present the first report of albino occurrences in the seed reproduction process of Prunus salicina and describe the cytological, physiological, and transcriptomic changes observed in albino seedlings. The albino seedlings which were observed in several plum cultivars exhibited abnormal chloroplast ultrastructure and perturbed stomatal structure. Compared to normal seedlings, the photosynthetic pigment contents in albino seedlings decreased by more than 90%, accompanied by significant reductions in several chlorophyll fluorescence parameters. Furthermore, substantially changed photosynthetic parameters indicated that the photosynthetic capacity and stomatal function were impaired in albino seedlings. Additionally, the activities of the antioxidant enzyme were drastically altered against the background of higher proline and lower ascorbic acid in leaves of albino seedlings. A total of 4048 differentially expressed genes (DEGs) were identified through transcriptomic sequencing, and the downregulated DEGs in albino seedlings were greatly enriched in the pathways for photosynthetic antenna proteins and flavonoid biosynthesis. GLK1 and Ftsz were identified as candidate genes responsible for the impaired chloroplast development and division in albino seedlings. Additionally, the substantial decline in the expression levels of examined photosystem-related chloroplast genes was validated in albino seedlings. Our findings shed light on the intricate physiological and molecular mechanisms driving albino plum seedling manifestation, which will contribute to improving the reproductive and breeding efforts of plums.

Physiological response mechanism of European birch (Betula pendula Roth) to PEG-induced drought stress and hydration.

Drought stress is also one of the important abiotic factors limiting plant growth and development, and the global temperature is rising year by year, resulting in a dry environment in most terrestrial forests, which will continue to affect the growth, development and reproduction of tree species in forests. European birch(Betula pendula Roth.) native to Europe, introduced to the mountains of eastern Liaoning in 1981 (annual precipitation of about 800mm), European birch relative to downy birch (B. pubescens)has strong adaptability and drought tolerance and cold tolerance, can grow normally in eastern Liaoning, but it is easy to be affected by drought at the seedling stage and cause death, many arid and semi-arid areas have no introduction and practical application of European birch, and there is less research on the drought resistance of European birch. This study used different concentrations of PEG-6000 treatment to simulate drought stress and clarify the changes of various growth physiological parameters and photosynthetic characteristics of European birch seedlings under drought stress, in order to investigate the physiological response mechanism of European birch under drought stress . This study used different concentrations of PEG-6000 treatment to simulate drought stress and clarify the changes of various growth physiological parameters and photosynthetic characteristics of European birch seedlings under drought stress, in order to investigate the physiological response mechanism of European birch under drought stress. The findings demonstrated that stress duration and increasing PEG concentration had a highly significant impact on the growth traits of European birch seedlings (p<0.01); With increasing stress concentration and stress time, antioxidant enzyme activity, membrane lipid peroxidation, and osmoregulatory substance concentrations increased significantly (p<0.01); With increasing stress concentration and duration, photosynthetic parameters and pigments decreased highly significantly (p<0.01); Under different PEG concentration treatments, the anatomical structure of seedling leaves changed more noticeably; there was a significant effect (p <0.05) on the change in mean stomatal length and a highly significant effect (p<0.01) on the change in mean stomatal structure. The study's findings serve as a foundation for the selection and breeding of new drought-tolerant European birch species, as well as a theoretical underpinning for the use of this species in landscaping and the promotion of new drought-tolerant species in China.

Epiphytic ferns and orchids adaptation mechanism based on stomatal structure and chlorophyll content in Urban Forest of Jember University, Indonesia

Epiphytic orchids and ferns in urban forests simulating a lowland tropical forest ecology were studied. This study aims to provide information about the epiphytes' adaptation to living in a dynamic microclimate of the tree canopy. Five epiphytes from the two taxa (orchids and ferns) were observed in their stomatal structure and chlorophyll contents. The stomatal type, size, and density were analysed with microscopic observation. The chlorophyll content was measured using a spectrophotometer. The orchids developed different mechanisms for water conservation compared to the ferns. Orchis develop smaller sizes and denser stomata to support photosynthesis rate as they had water absorbers and storage organs. On the other hand, ferns tend to avoid drought stress by developing fewer numbers and sparse stomata. The higher chlorophyll content in ferns was for photosynthesis efficiency purposes

The Effects of Enhanced Ultraviolet-B Radiation on Leaf Photosynthesis and Submicroscopic Structures in Mangifera indica L. cv. ‘Tainong No 1’

Objective: In the future, the stress of enhanced UV-B radiation on the Earth will first affect the photosynthesis of plants, including mangoes. Therefore, it is necessary to study the effects of enhanced UV-B radiation on the photosynthesis of mangoes. Methods: ‘Tainong No 1’ mango trees in the field were selected as the experimental material and divided into 2 groups: one group was shined under 96 kJ·m−2·d−1 UV-B lamps for artificially simulated treatment of enhanced UV-B radiation, and the other group was shined under sunshine directly as the control (CK). The main photosynthetic physiological indicators were measured with conventional methods, and the expression levels of the genes encoding large and small subunits of the Rubisco enzyme were measured with fluorescent qPCR. The changes in stomatal morphology and chloroplast structure were observed with scanning electron microscopy and transmission electron microscopy. Results: The content of malondialdehyde (MDA) and the relative conductivity in the leaves of the treatment tended to be significantly higher than those of the CK. The net photosynthetic rate (Pn) of the treatment tended to decrease and be lower than that of CK. The dynamics of intercellular CO2 concentration (Ci) of the treatment and CK changed differently from each other but generally tended to decrease, and that of the treatment tended to be significantly higher than that of CK. The stomatal conductance (Gs) of the treatment and CK both generally decreased, and that of the treatment was always significantly lower than that of CK. The contents of chlorophyll a, chlorophyll b and total chlorophyll and the ratio of chlorophyll a/b of the treatment were lower than those of CK, while the carotenoid content showed the opposite trend. The stomata and the surface of leaves of the treatment were sunken and damaged, respectively. The palisade tissue, spongy tissue and upper epidermis thickened more, and the total thickness significantly increased. Meanwhile, the ratio of palisade tissue to spongy tissue decreased. During treatment, the chloroplasts were swollen and shortened, the number of chloroplasts was reduced, the starch grains were degraded, and the grana lamella were distorted, loosely arranged and blurred. The expression of the genes encoding the Rubisco large subunit (rbcL) in the treatment was significantly inhibited, while that encoding the Rubisco small subunit (rbcS) decreased first and increased later. In conclusion, 96 kJ·m−2·d−1 enhanced UV-B radiation treatment caused damage to the leaf cell membrane system. This led to stomatal limitation of photosynthesis by destroying the stomatal structure and nonstomatal limitation of photosynthesis by damaging the submicrostructure of the chloroplasts and downregulating the expression of rbcL. The leaves may resist the photosynthetic damage caused by enhanced UV-B radiation by upregulating rbcS expression as much as possible.

THE EFFECTS OF ACID MIST ENVIRONMENT ON PLANT GROWTH: A REVIEW

The wet (rain, snow, fog, sleet, dew) and dry (transport of aerosol, particles and gases) deposition of acidic substance in environment results due to human, automobile, fossil fuel burning and industrial activities. Acid deposition is worldwide environmental degradation problems and in recent years these acidic materials are increasing at alarming scale in the environment both in developed and developing countries, including Pakistan. Some scientific literature survey reports suggest that plant growth and agriculture yield decrease due to consequence of acid rain. In addition, acid rain is found responsible for producing toxic effects on the morphological parameters of agricultural crop. The evidence collected from last more than fifty years showed the common significant effects of acid rain on seed germination percentage, seedling height, root hair and structure, alteration in leaf anatomy, size and area, stomatal structure, size, pollen germination, photosynthetic pigments and physiological changes in herbs, shrubs and trees. Still, little is known on the impact of acid rain on plant growth. This study was aimed to review the effects of acid mist on growth performances of some selected plant species. This review is contributed with the help of literature survey, research work published on the impact of acid rain on the plant growth.

Comparison of Stomatal Structure and Distribution between Ovules and Leaves in Ginkgo biloba

Stomata are plant epidermal structures that play essential roles in photosynthesis, respiration, and transpiration. Although stomata on plant leaves have been extensively studied, their structure and distribution on other organs remain poorly understood. The “living fossil “, Ginkgo biloba, has naked ovules that are thought to be primitive reproductive structures in ancient seed plants. Therefore, we hypothesized that there are some distinct stoma features in G. biloba ovules that have not been reported. In this study, we investigated the morphological development of stomata on ovules and leaves of Ginkgo biloba using scanning electron microscopy, then examined the anatomical characteristics of the general stalk and petiole using semi-thin sectioning. We found that stomata were distributed on the epidermis of the whole ovule, except near the micropyle; these stomata persisted until harvest, indicating that ovules perform gross photosynthesis to an extent similar to the photosynthesis observed in leaves, which is beneficial to ovule development. Ovule and leaf stomata share similar orientation, composition, and development; however, their distribution and subsidiary cell morphology significantly differ. The morphology of the general stalk was similar to the morphology of the petiole, but xylem cell development was minimal, and no sclerenchyma cells were present beneath the epidermis; these findings suggested that the general stalk is biomechanically weaker than the petiole. Overall, these results suggest that despite their differences, G. biloba ovules and leaves share many morphological and anatomical similarities in terms of stomatal architecture and stalk anatomy. These findings will help to elucidate the leaf origins of “flowers” in ancient plants.

Effects of Shading on Anatomical Aspects and Chlorophyll and Carotenoid Contents in Paricá

Paric&amp;aacute; (Schizolobium parahyba variety amazonicum) is an important species for reforestation programs in the Amazon; nevertheless, the anatomical and physiological parameters of the seedlings of this species under shading are not yet fully understood. This study evaluated the chlorophyll and carotenoid contents, the stomatal structure, and the stomatal position in the leaf epidermis under shading of paric&amp;aacute; seedlings. The experiment comprised a randomized block design in a subdivided plot scheme, with two sources (Belterra and Urup&amp;aacute;) and different shading levels (full sun, 30%, 50%, and 70%). At 100 days after sowing, we performed the analyses of photosynthetic pigment concentration and leaf anatomy. We found that the leaf is hypoestomatic with paracitic stomata and unicellular filiform trichomes on both sides. Higher levels of shading increased the contents of chlorophyll a and b and reduced the stomata density and carotenoid contents in the leaves of young paric&amp;aacute;, showing that paric&amp;aacute; has phenotypic plasticity to shading.

Evaluation on the water state of frozen dough and quality of steamed bread with proper amount of sanxan added during freeze-thawed cycles

Based on the strong hydrophilicity, freeze-thawed stability and special “gel-forming in cold water, and gel strength-strengthening during heating” properties of water-soluble sanxan, the evaluation on the water state of frozen dough and quality of steamed bread with proper amount of sanxan added during freeze-thawed cycles was performed. The addition of 0.5% sanxan reduced the freezable water content, slowed down the loss and migration of water and inhibited ice recrystallization, and improved the freeze-thawed stability of frozen dough during freeze-thawed cycles. Additionally, 0.5% sanxan increased the hardness, chewiness and springiness of steamed bread. Meanwhile, the specific volume and stomatal structure were improved, indicating 0.5% sanxan alleviated the deterioration of steamed bread quality. This study provides a rationale for the alteration on water state of frozen dough and quality of steamed bread with 0.5% sanxan added during freeze-thawed cycles, which is of great significance to further developing the application of sanxan in frozen foods.

Genotypic variability and physio-morphological efficiency of buckwheat (

Context Crop production in Eastern Himalaya is constrained by combined effects of soil acidity and moisture deficit during post monsoon under a changing climate. Aim This study aimed to identify potential buckwheat genotypes and stress mechanisms in hill environments of Meghalaya (India). Method Field and microcosm experiments were conducted to study field performance, genotypic variability and physio-morphological efficiency in buckwheat. Key results Substantial genetic variability for shoot length (30.3–110 cm), crop canopy distribution (3.0–7.5 number of primary branches), leaf area retention (15.7–60.2 cm2/two leaves), 1000 seed weight (16.2–34.7 g) and seed yield (0.088–1.31 metric tonne (MT)/ha) was observed. Mean grain yield of buckwheat genotypes was 0.446 MT/ha whereas IC13411, IC24298 and IC37305 produced significantly higher seed yield (1.31, 1.28 and 1.14 MT/ha, respectively) accounting to 1.93, 1.87 and 1.67 times higher than average yield (0.680 MT/ha). Genotypes like IC42416, EC323730 and EC218784 have lower crop yields (0.8, 1.02, 0.93 MT/ha respectively). Interestingly, few high yielders (IC13411 and IC24298) exhibited higher photosynthetic rate (46.1 and 32.3 μmol/m2.s), increased stomatal conductance (311.0 and 326.2 mmol/m2.s), leaf chlorophyll (2.47 and 2.55 mg/g fresh weight (FW)) and carotenoids (95 and 106.3 μg/g FW). Chlorophyll a and b ratio (3.3 and 3.0) and total chlorophyll to carotenoids (4.2 and 4.0) were higher in high yielders (IC13411 and IC24298) compared to other low yielders. Conclusions Robust root systems, stomatal structure and higher cuticle wax ideally enhanced water use efficiency (WUE) and drought tolerance in high-yielding buckwheat genotypes. Implications IC13411 and IC24298 are promising for enhanced productivity in the mountainous ecosystem of Meghalaya.

On the identity of the genus Epacrolaimus Andrássy, 2000 (Nematoda, Dorylaimida), with new insights into its phylogeny.

The type species of the genus Epacrolaimus, Epacrolaimus declinatoaculeatus, is studied from the re-examination of type material of Aporcelaimus vorax, its junior synonym, and the observation of several Iberian populations and a few Iranian specimens. Morphologically, it displays a recognizable morphological pattern characterized by, among other features, the incurved nature of its odontostyle aperture, presence of perioral liplets or lobes, lip region 24-31 μm wide, odontostyle 21-25 μm long and comparatively anterior location of S2N pharyngeal gland nuclei. Nevertheless, variations in some morphological traits (vagina shape and tail shape) and in several morphometrics (body length, uterus length, vulva position, tail length and spicule length) are also noted. Sequences of D2-D3 domains of the 28S rDNA, 18S rDNA and COI mtDNA were obtained from several Iberian populations. Their analyses, in particular those from D2-D3 sequences, revealed the existence of a highly supported clade ((Epacrolaimus + Sectonema) + Metaporcelaimus), with a closer relationship between Epacrolaimus and Palaearctic populations of Sectonema, whereas the remaining aporcelaimid genera occupied placements in other clades. These results are discussed, with especial emphasis on the intricate separation of Epacrolaimus and Sectonema, which display significantly different protruding stomatal structure in spite of their close evolutionary relationship as derived from molecular trees.

Discovery of a new species of Adder\u2019s tongue fern from India with comparative analysis of morphological and molecular attributes

Eusporangiate fern genus Ophioglossum L. is commonly known as Adder’s tongue fern as its fertile frond gives the appearance of snake tongue. A new species in this fern genus, O. trilokinathii belonging to Ophioglossaceae family has been discovered from the plateau region of Rajasthan State of northwestern India. The new species can be distinguished from other taxa of this genus by its smaller habit, subglobose-tuberous rhizome, basipetal emergence of young roots, aggregation of old decaying roots on rhizome apex, fertile stalk as well as spike short and thick, trophophylls in rosette, ovate or orbicular and a unique sporoderm sculpture pattern under SEM having broad reticulations with thick and raised muri enclosing large hexagonal or irregular areas on the distal and proximal faces of the spores hitherto unreported in any of the presently known taxa of Ophioglossum. In addition, comparative study of stomatal structure, foliar anatomy and nucleotide sequence data of its three chloroplast DNA markers (trnL-F, rbcL and psbA-trnH) was carried out. In view of all the attributes including habitat, ecology, morphology, foliar anatomy, stomatal features, palynology and molecular phylogenetic data, the present study suggests that the Ophioglossum specimen collected from plateau region of Rajasthan represents a hitherto undescribed species thereby warranting its establishment as O. trilokinathii sp. nov. A detailed comparative account of the new taxon with its allied species has also been provided.

Response of Leaf Traits of Eastern Qinghai-Tibetan Broad-Leaved Woody Plants to Climatic Factors

Plant ecologists have long been interested in quantifying how leaf traits vary with climate factors, but there is a paucity of knowledge on these relationships given a large number of the relevant leaf traits and climate factors to be considered. We examined the responses of 11 leaf traits (including leaf morphology, stomatal structure and chemical properties) to eight common climate factors for 340 eastern Qinghai-Tibetan woody species. We showed temperature as the strongest predictor of leaf size and shape, stomatal size and form, and leaf nitrogen and phosphorus concentrations, implying the important role of local heat quantity in determining the variation in the cell- or organ-level leaf morphology and leaf biochemical properties. The effects of moisture-related climate factors (including precipitation and humidity) on leaf growth were mainly through variability in leaf traits (e.g., specific leaf area and stomatal density) related to plant water-use physiological processes. In contrast, sunshine hours affected mainly cell- and organ-level leaf size and shape, with plants developing small/narrow leaves and stomata to decrease leaf damage and water loss under prolonged solar radiation. Moreover, two sets of significant leaf trait-climate relationships, i.e., the leaf/stomata size traits co-varying with temperature, and the water use-related leaf traits co-varying with precipitation, were obtained when analyzing multi-trait relationships, suggesting these traits as good indicators of climate gradients. Our findings contributed evidence to enhance understanding of the regional patterns in leaf trait variation and its environmental determinants.

Linking exogenous foliar application of glycine betaine and stomatal characteristics with salinity stress tolerance in cotton (Gossypium hirsutum L.) seedlings

BackgroundGlycine betaine (GB) plays a crucial role in plants responding to abiotic stresses. Studying the physiological response of cotton seedlings to exogenous GB under salt stress provides a reference for the application of GB to improve the resistance of cotton seedlings under salt stress. The purpose of this research is to examine the impacts of foliar-applied GB on leaf stomatal structure and characteristics, gas exchange and chlorophyll fluorescence characteristics and plant growth indicators of Gossypium hirsutum L. under NaCl stress conditions.ResultsUnder the salinity of 150 mM, the four concentrations of GB are 0, 2.5, 5, and 7.5 mM, and the control (CK) was GB-untreated non-saline. Salt stress negatively affected leaf stomata as well as gas exchange and chlorophyll fluorescence and decreased plant growth parameters of cotton seedlings. The treatment with 5 mM GB significantly increased the evolution of photosynthetic rate (Pn), transpiration rate (Tr), intracellular CO2 concentration (Ci) and stomatal conductance (gs) compared to the GB-untreated saline treatment. The Exogenous foliar-applied GB has sustainably decreased the carboxylation efficiency (Pn/Ci) and water use efficiency (WUE). The concentration of 5 mM GB leads to a significant improvement of leaf stomatal characteristics. The leaf gas exchange attributes correlated positively with stomatal density (SD), stomatal length (SL) and stomatal with (SW).ConclusionThe overall results suggested that exogenous foliar supplementation with GB can effectively alleviate the damage of salt stress to cotton seedlings. The effect of applying 5 mM GB could be an optional choice for protecting cotton seedlings from NaCl stress through promoting the stomatal functions, photosynthetic activities and growth characteristics.

Drought tolerance related to root morphology and stomatal structure of the 12 seasonal rice varieties (Oryza sativa L.) under artificial drought conditions

Drought-tolerant rice varieties are one of the best choices to avoid the effects of drought. A Randomized Complete Block Design (RCBD) with three replications was used for the experiment. 12 seasonal rice were tested under artificial drought conditions. The criteria were assessed through the morphology, root anatomical structure, and stomatal leaves that were suitable for the drought environment. The results showed that 3 seasonal rice were well adapted to this condition.Sophinh had the smallest density and area of stomata (529.3 stomata/mm2 and 88.6 μm2 respectively), they helped reduce water loss. Xuong ga do had the highest ratio of deep roots 58.7% which could increase the ability to take water from the deep soil layer. Bang nau had a thick root diameter of 876.3 μm and a stele root area of 54.4x103 μm2 containing a high number and more areas of late metaxylems (5.6 and 12x103 μm2 respectively). These factors helped increase water flux from root to shoot. Correlation among the density of stomata, number of roots, and the number of late metaxylem were negative while correlation among diameter of roots, number of late metaxylem, and total areas of late metaxylem were positive. These results were useful for developing drought-tolerant rice varieties.