Stomata Density Research Articles

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

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

Study of some Physiological and Molecular Indicators of Bread Wheat Treated with Colchicine

During the winter agricultural season of 2022-2023, a field experiment was carried out in the Al-Basatin Al-Sharqiya, located 4 km away from the center of Al-Muthanna governorate. The objective of this study was to investigate various anatomical and genetic parameters of wheat varieties under the influence of the mutagenic alkaloid colchicine at concentrations of 0, 250, 500, and 750 mg L-1. The study employed a split plot design with three replications. The main plots consisted of different concentrations of the colchicine compound, while the secondary plots comprised four varieties (Ibaa99, Mawadah, Bohuth 22, Babel). The statistical analysis yielded significant variations in the anatomical and molecular traits among the cultivars. Notably, the cultivar Mawada demonstrated superior performance in terms of stoma density on the upper leaf surface, with an average of 118.15 stomata mm-2. Conversely, the Babel variety exhibited the highest average stoma density of 113.70 stomata mm-2 on the lower leaf surface. Regarding Bohuth 22, it demonstrated notable proficiency in terms of stoma length, exhibiting an average measurement of 3.82 μm for both the upper and lower leaf surfaces. Additionally, it displayed the highest average stoma width for the lower surface, measuring at 2.66 μm. The highest mean stomatal density for both the upper and lower leaf surfaces (114.1, 104.44 stomata mm-2) was observed at a colchicine concentration of 750 mg L-1. Regarding the intersection of the treatments, it was observed that treatment C1V3 exhibited superior performance in terms of the dimensions of the stoma, specifically the length and width on the lower surface of the leaf. The average difference between the measurements was found to be 4.40-2.96 μm, consecutively. The C2V2 treatment demonstrated superior performance in relation to the stomatal density observed on the upper surface of the leaf, exhibiting an average of 132.6 stomata mm-2. The treatment labelled as C2V4 exhibited the highest average stomata density (131.85 stomata mm-2) on the lower surface of the leaf. The molecular analysis conducted using RAPD-PCR technology revealed that the primer OPA 9 exhibited a total of 37 bands. Among these bands, 6 were found to be unique, while the remaining 31 bands displayed divergence. The OPA12 primer exhibits a minimum total of 29 bands, consisting of 24 distinct bands and 5 unique bands. Notably, all primers demonstrate a 100% occurrence of differentiated bands.

Acclimation of subarctic vegetation to warming and increased cloudiness.

Subarctic ecosystems are exposed to elevated temperatures and increased cloudiness in a changing climate with potentially important effects on vegetation structure, composition, and ecosystem functioning. We investigated the individual and combined effects of warming and increased cloudiness on vegetation greenness and cover in mesocosms from two tundra and one palsa mire ecosystems kept under strict environmental control in climate chambers. We also investigated leaf anatomical and biochemical traits of four dominant vascular plant species (Empetrum hermaphroditum, Vaccinium myrtillus, Vaccinium vitis-idaea, and Rubus chamaemorus). Vegetation greenness increased in response to warming in all sites and in response to increased cloudiness in the tundra sites but without associated increases in vegetation cover or biomass, except that E. hermaphroditum biomass increased under warming. The combined warming and increased cloudiness treatment had an additive effect on vegetation greenness in all sites. It also increased the cover of graminoids and forbs in one of the tundra sites. Warming increased leaf dry mass per area of V. myrtillus and R. chamaemorus, and glandular trichome density of V. myrtillus and decreased spongy intercellular space of E. hermaphroditum and V. vitis-idaea. Increased cloudiness decreased leaf dry mass per area of V. myrtillus, palisade thickness of E. hermaphroditum, and stomata density of E. hermaphroditum and V. vitis-idaea, and increased leaf area and epidermis thickness of V. myrtillus, leaf shape index and nitrogen of E. hermaphroditum, and palisade intercellular space of V. vitis-idaea. The combined treatment caused thinner leaves and decreased leaf carbon for V. myrtillus, and increased leaf chlorophyll of E. hermaphroditum. We show that under future warmer increased cloudiness conditions in the Subarctic (as simulated in our experiment), vegetation composition and distribution will change, mostly dominated by graminoids and forbs. These changes will depend on the responses of leaf anatomical and biochemical traits and will likely impact carbon gain and primary productivity and abiotic and biotic stress tolerance.

Coordination of hydraulic and functional traits in ten species of trees of the Sonoran Desert

Leave’s vein xylem and stomata hydraulic traits should be critically linked to modulating plant responses to drought in leaves of desert species, influencing traits at the whole-plant level and promoting adaptation. We tested for coordination among leaf vein xylem anatomical traits across different hierarchical orders (hydraulic vessel diameter, vein area, free veins per area, areolas per area, total free veins number, total areola number) and stomatal traits (stomatal size, stomatal density, stomatal index, leaf total stomatal area, leaf total stomatal number) as well as their relationship with the leaf area in ten tree species from the Sonoran Desert scrub, Mexico. Moreover, these traits were correlated with other hydraulic and functional traits associated with resource use strategies (hydroscape area, stem-specific density, leaf mass per area, and leaf phenology). Leaf total stomatal area and number were positively associated with vessel diameters at the midrib and with leaf total free terminal veins and areola number, indicating coordination between water transpiration and transport. Also, interspecific differences fit species along a physiological resource use spectrum, following an exploitative vs. conservative physiological axis. Accordingly, species with lower leaf longevity (LL) and foliage duration at the canopy (FD) displayed higher values of stomatal indices and free vein densities, higher stomata density; and anatomical traits related to higher hydraulic conductance and gas exchange in comparison to species with higher LL and FD. Therefore, in this community, species have been selected to take advantage of different temporal hydrological niches to enhance survival under unpredictable and highly seasonal water availability.

Improving drought tolerance in soybean by classical breeding leads to physiological adjustments of photosynthesis and stomata functioning

Soybean (Glycine max) is one of the main crops cultivated worldwide and drought is the main abiotic stress affecting its production. However, breeding towards drought tolerance is often set aside due to the difficulties in phenotyping. The aim of this study was to design an effective and simple screening technique that allows to discriminate genotypes according to their drought response and to identify physiological traits responsible for a superior tolerance. This rapid screening evaluated morphological (shoot and root length and weight) and developmental traits (days to germination and plant establishment) of 604 genotypes under control and drought conditions. Two genotypes with contrasting responses (Sensitive Genotype and Tolerant Genotype, SG and TG, respectively) were selected according to their performance in the screening, and were subjected to further testing in order to physiologically characterize the drought response of the chosen cultivars. Wilting, normalized transpiration ratio, leaf gas exchange parameters, water use efficiency (WUE) and stomatal characterizations were performed. TG plants exhibited slow wilting and higher WUE when subjected to drought treatments, product of a reduced water loss due to an anticipated stomatal closure which allowed to preserve soil moisture. Besides, under control conditions, the TG genotype presented a higher stomatal aperture index and a bigger density of epidermal cells and stomata than the drought-sensitive genotypes analyzed. In summary, the analysis of easily quantifiable traits, as the growth of the plant aerial organs and root development, together with the plant development timing, allowed us to select two soybean cultivars with contrasting drought responses. In our opinion, this selection method might be efficiently applied for the selection of drought tolerant cultivars in plant species of agronomic interest.

Anatomical Characteristics of Rhizophora’s Leaves as Mangrove Plant Adaptation at Banyuurip Mangrove Center

Rhizophora is a genus of mangrove plants that dominates the Banyuurip Mangrove Center. This plant certainly has an anatomical structure as a form of adaptation to high salinity environments. The purpose of this study was to describe the anatomical characteristics of the leaves of the three Rhizophora species as an adaptation form of mangrove plants in the Banyuurip Mangrove Center and the anatomical variations of the leaves between species. This type of research was descriptive observational in the form of leaf anatomy observations using the whole mount method for longitudinal incisions and the paraffin method for transverse incisions. The results showed that there were anatomical variations among the three Rhizophora species in the Banyuurip Mangrove Center including epidermal cell size, number of epidermal cells, cork warts, number of hypodermis cell layers, hypodermis cell size, stomata size, number of stomata, stomata index, and stomata density. The anatomical characteristics of the leaves of the three Rhizophora species which act as a form of adaptation to mangrove plants are the presence of hypodermis tissue which functions to store water and salt to remove salt content in plants when they abort their leaves, low density of stomata and the presence of cuticles on the adaxial surface of leaves which play a role in reducing the rate of transpiration thus maintaining water to support plant development in saline conditions, cork warts which function as a medium for expelling salt on leaves.

Pengaruh Kolkisin pada Stomata Daun Dendrobium

This study aims to determine the effect of colchicine on the stomata of dendrobium orchids. This research method is quantitative. This research used 2 factorial RAK where the first factor was the variety treatment consisting of dendrobium venus purple algis (ALG) and dendrobium transient pink frederika (FRD). The second factor, namely the colchicine concentration treatment, consisted of control (0 ppm), 4000 ppm, 5000 ppm and 6000 ppm. The research parameters observed were stomata density, stomata length and width. The results showed that dendrobium orchid varieties FRD and ALG were treated with several concentrations of colchicine with the average parameters of open stomata, stomata density, length and width of somata not significantly different from each treatment or control. Colchicine still does not appear to have an effect on the stomata of the FRD and ALG varieties of dendrobium orchids. Based on observations of the stomata, the average length of the stomata at each concentration is still not classified as diploid because it is <1.25x the length of the control stomata. In conclusion, the observed parameters have no effect or are significantly different.
 
 Keywords: Dendrobium Orchid, Colchicine, Stomata

Assessment of the Drought-Tolerance Criteria for Screening Peach Cultivars

The article presents an analysis of the artificial dehydration effect of peach leaf tissues, simulating natural drought, on various physiological, morphological, and anatomical parameters described in the literature, associated with the trait of drought resistance. An investigation aimed to identify the most informative criteria for peach drought resistance which correlate with water loss during dehydration. The results present an assessment of the amount of water loss in 60 peach cultivars selected from different geographical areas and having different genetic origins. Four contrasting genotypes were identified, based on the results of the cluster analysis performed on the cultivar’s water regime. The influence of water regime parameters (leaf water content, water saturation deficit, dynamic of water loss), the morphological and anatomical structure of the leaf, the content of photosynthetic pigments, and the activity of the photosynthetic apparatus on drought resistance were investigated for selected peach cultivars. It was revealed that the most informative criteria for assessing drought resistance were dry and fresh leaf weight, leaf blade length, leaf width, and area (among morphometric parameters); stomatal pore length, stomata density, adaxial and abaxial epidermis thickness, and adaxial cuticle thickness (among anatomical parameters); and Fv/Fm—maximum photochemical quantum yield of PSII, Y(NO)—quantum yield of unregulated non-photochemical light energy dissipation in PS II and Y(NPQ)—controlled quantum losses (among indicators of photosynthetic activity).

Leaf micromorphology affects the particulate matter retention in herbaceous plants: An in situ interspecies comparison

AbstractGarden plants can absorb and retain atmospheric particles and are important for remediating environmental pollution. As an important biological constituent of urban landscape, herbaceous plants can provide ecosystem service such as particulate matter (PM) retention. However, the evaluation of this ecosystem service for herbaceous plants has been seldom made. The present study compared the PM retention capacity of four herbaceous plants commonly used for urban greening in North China—Liriope spicata (Thunb.) Lour., Lolium perenne L., Festuca elata Keng ex E.B.Alexeev, and Poa pratensis L. and explored the correlation between leaf micromorphological traits and PM retention using an in situ experiment. PM with different particle sizes, including PM>10 (10–100 µm), PM10 (2.5–10 µm), and PM2.5 (<2.5 µm), were separately evaluated. We found that L. spicata had the greatest PM retention capacity for all particle sizes among the four species. Electron microscopy revealed that leaves with higher groove proportion, larger stomatal size and greater densities of stomata and trichome generally had higher PM retention capacity. The study showed the correlation between leaf micromorphology and PM absorption, providing a scientific basis for further quantitative studies on the ecosystem service of PM absorption provided by herbaceous plants.

Automated estimation of stomatal number and aperture in haskap (Lonicera caerulea L.).

This study developed the reliable Mask R-CNN model to detect stomata in Lonicera caerulea. The obtained data could be utilized for evaluating some characters such as stomatal number and aperture area. The native distribution of haskap (Lonicera caerulea L.), a small-shrub species, extends through Northern Eurasia, Japan, and North America. Stomatal observation is important for plant research to evaluate the physiological status and to investigate the effect of ploidy levels on phenotypes. However, manual annotation of stomata using microscope software or ImageJ is time consuming. Therefore, an efficient method to phenotype stomata is needed. In this study, we used the Mask Regional Convolutional Neural Network (Mask R-CNN), a deep learning model, to analyze the stomata of haskap efficiently and accurately. We analyzed haskap plants (dwarf and giant phenotypes) with the same ploidy but different phenotypes, including leaf area, stomatal aperture area, stomatal density, and total number of stomata. The R-square value of the estimated stomatal aperture area was 0.92 and 0.93 for the dwarf and giant plants, respectively. The R-square value of the estimated stomatal number was 0.99 and 0.98 for the two phenotypes. The results showed that the measurements obtained using the models were as accurate as the manual measurements. Statistical analysis revealed that the stomatal density of the dwarf plants was higher than that of the giant plants, but the maximum stomatal aperture area, average stomatal aperture area, total number of stomata, and average leaf area were lower than those of the giant plants. A high-precision, rapid, and large-scale detection method was developed by training the Mask R-CNN model. This model can help save time and increase the volume of data.

Response of vegetative phase growth of very early maturing rice plant to the application of liquid biosilica in paddy field

An increase in the cropping index causes the land to be cultivated more intensively and has impact on decreasing Silica content (Si) so that it is necessary to add Si to support the growth of rice plants, especially on intensive land. This research aims to study the effect of biosilica on the growth of the vegetative phase of several very early maturing rice varieties. The research was conducted from September to December 2022 in Gorontalo using a Split Plot Design. The variety as the main plot and dose of liquid biosilica as a subplot. The results showed that the treatment of Inpari 19 variety with biosilica dose of 4.5 L ha−1 had the highest number of stomata and stomata density. Individually, the Cakrabuana variety has the highest plant height, the highest number of tillers and the smallest flag leaf angle. Meanwhile, biosilica at a dose of 4.5 L ha−1 had the highest plant height and the smallest flag leaf angle. In addition, treatment of Inpari 13 and Inpari 19 varieties with biosilica dose of 3.0 L ha−1 gave the best effect on the development of blast disease intensity.

Green Plants as a Sustainable Solution to Air Pollution

In today’s global context, the escalation of air pollution stands out as an immensely critical environmental challenge that has attained a worldwide magnitude. This pressing issue not only impacts every living organism on our planet but is also intricately linked to the phenomenon of climate change. The significant increase in vehicular traffic, rapid urbanization, and infrastructure development have indirectly contributed to a higher concentration of harmful gaseous and particulate pollutants in the atmosphere, posing serious risks to human health. Extensive research has thoroughly documented the adverse effects of these air pollutants, with mortality and morbidity rates varying depending on the type of pollutant and the duration of exposure. However, amidst this crisis, green plants emerge as a cost-effective and promising solution to combat environmental pollution, presenting several additional benefits. Specifically, pollutiontolerant plant species are crucial in reducing ambient air pollution and the urban heat island effect. To assess a plant’s tolerance towards air pollution, experts use the air pollution tolerance index (APTI), which calculates crucial factors such as ascorbic acid, total chlorophyll, pH, and relative water content in the plant. This determination provides a reliable method for categorizing plants into either tolerant or sensitive types in the face of air pollution. Moreover, the morphological characteristics of leaves, such as stomata distribution and density, cuticle thickness, and trichome density, play an essential role in adsorbing and absorbing particulate matter from the air. These inherent qualities further enhance plants’ potential to combat air pollution in a sustainable manner, making them valuable assets for the future. In light of this, the present review highlights the impressive capacity of plants to remediate air pollutants and explores the various strategies employed in this crucial endeavor. By leveraging the remarkable capabilities of green plants, we have the opportunity to address the air pollution crisis and embrace a sustainable path for the times to come. These remarkable organisms could be the sustainable saviors we need to protect our environment and secure a healthier future for all.

Nicotiana benthamiana as a model plant host for Fusarium verticillioides to investigate RNA interference, cross-kingdom RNA exchange, and competitive endogenous RNA (ceRNA) network.

Fusarium verticillioides is among the most devastating fungal pathogen of cereals. Therefore, it is crucial to employ effective and long-term strategies for managing F. verticillioides for sustainable agriculture. RNA interference (RNAi) being a natural defense mechanism of plants via regulation of gene expression, has emerged as a promising tool for eradicating pathogens. RNAi also operates between the host and pathogen through RNA exchange. RNAi interacts with competitive endogenous RNAs (ceRNAs) including long non-coding RNA (lncRNA), microRNA (miRNA), and mRNA. Due to the lack of an elaborate model to investigate all these mechanisms, this study aimed to establish a Nicotiana benthamiana (Nb)-F. verticillioides (Fv) phyto-pathosystem as an experimental model. Nb seedlings were inoculated with Fv, and the pathogenicity was monitored morphologically, microscopically, biochemically, and transcriptionally. To observe the role of RNAi and RNA-exchange in pathogenicity, Nb-miR172 and Nb-miR399 targeting Nb-lncRNA-IPS (Induced by Phosphate Starvation1) and Nb-AP2 (Apetala2) and Nb-PHO2 (phosphate over-accumulator) ceRNA network and Fv-V-ATPase (Vesicle-fusing ATPase) targeted by Nb-miR172 were investigated. As a result, epidermal cell density, leaf area, petiole length, and chlorophyll content were reduced while the density of stomata and trichome and phenolic content and the activity of ascorbate peroxidase (APX) and glutathione reductase (GR) were increased in response to Fv infection in Nb. The expression of AP2 and PHO2 were downregulated against Fv but no significant changes were detected in IPS, miR172, and miR399 expression. These findings suggested the Fv-Nb phyto-pathosystem as a useful experimental model to reveal genetic regulations.

The relationship between the wettability and the density of stomata

stomata are channels for respiration of plants, and they are vital to keep it unblocked. In nature, in order to avoid the surface stomata being covered by water and ensure the normal respiration of stomata, plant leaves in nature are realized by a variety of methods, among which the difference surface wettability plays a crucial role in the distribution density of stomata. To explore the relationship between the wettability and the stomata density, this thesis investigates how the top and bottom density of stomata on plant surface affect the survivability of elm leaves (plant in the Ulmaceae family). Here, we find its lower surface with superhydrophobic function is covered by large amount of stomata. While the bottom surface with hydrophilic performance is smooth and covered by a small amount stomata. This research reveals the significant of waterproof function to the survival of leaf and has potential application in air exchange underwater.

The Effect of Air Pollution on The Stomata Characteristics Pigeon Orchid (Dendrobium crumenatum) Leaves, In the Tasikmalaya

This study aims to determine the effect of air pollution on the stomata characteristics in Pigeon Orchid (Dendrobium crumenatum) leaves in Tasikmalaya. This research is quantitative. The Samples were taken through survey method with purposive sampling technique in the Singaparna Bus Station as an exposed area with the highest air pollution, Sukaraja-Mangunreja street as an exposed area with the moderate air pollution, and Mount Galunggung as an exposed area with the the lowest air pollution. The characteristics of the stomata observed using an Optilab camera type Professional Model Series MTN001 which already has the Image Raster application and previously calibrated with an object glass micrometer at 400 x magnifications. The Data analysed quantitatively and descriptively using one way ANOVA test. The results showed that different levels of air pollution could affect the characteristics of the stomata. Stomata in areas with high air pollution have the highest stomata index and stomata density, namely 8.2% and 326.11/mm2, with the category of medium density and oval stomata shape. Stomata in areas with moderate air pollution have the lower stomata index and stomata density, namely 7.3% and 256.47/mm2, with the low-density category and round stomata shape. Meanwhile, stomata in areas with low air pollution have the lowest stomata index and stomata density, namely 5.7% and 256.47/mm2, which indicate the category of low density and the shape of the stomata is round.

Production of Tetraploid Plants from Cotyledons of Diploid Melia volkensii Gürke

Polyploidy was induced in Melia volkensii (Mukau), a valuable native tree from the semi-arid regions of East Africa. Cotyledons of diploid M. volkensii (2n = 2x = 28) were treated with oryzalin for 0 (control), 1, 2, or 3 h with or without pretreatment with 1.1 µM thidiazuron. Cotyledons treated with 10 mg·L−1 oryzalin for three hours yielded 40% tetraploids. Pretreatment of cotyledons with thidiazuron for 18 days followed by treatment with oryzalin increased tetraploid plant production to 52.5%, but this also yielded more mixoploids. Compared to diploid M. volkensii, the tetraploid in vitro and young potted plants were compacter, with thicker stems, wider leaves, and a low density of longer and wider stomata. In the coming years, tetraploid M. volkensii plants will be observed in field trials and serve as a basis for further breeding efforts.

Variation and phenetic relationships of Dendrophthoe pentandra (L.) Miq. from various host trees based on morphological characters

Dendrophthoe pentandra (L.) Miq.; Loranthaceae) is a shrub parasitic on various host tree species. This species is often used for herbal medicinal ingredients by local communities based on the spesies of host tree. The morphological characteristics of D. pentandra are important to study because their adaptation to different host trees may resulting population of ecotypes. This study aims to determine the variation of D. pentandra accession characters on different host tree species based on morphological characters and to determine morphological phenetic relationships between accessions. Besides studies of D. pentandra accessions in Yogyakarta Province have never been conducted in full. Sample collection (accession) of D. pentandra was conducted for various host tree species from various locations, including roots, stems, leaves, flowers, and fruit. Morphological characterization and scoring of each accession were conducted to create a similarity matrix using the Jaccard Coefficient formula. Based on the similarity matrix between OTUs and the UPGMA algorithm, it can be formed into a dendrogram. The results showed that the morphological variations of D. pentandra were found in phyllotaxis, leaf thickness, petiole length, number of stomata density per field of view, flower color, crown tube length, corolla lobe length, petal length, stamen : corolla lobe ratio, fruit color, and seed color. The population of D. pentandra in Yogyakarta can be divided into two groups, D. pentandra which has alternate and opposite arrangements in phyllotaxis. The accession dendrogram of D. pentandra in Yogyakarta was divided into five clusters starting from a similarity index of 0.089 to 0.952. Thus, the diversity of morphological variations of D. pentandra on host trees is high.

Economically important species of Asteraceae: An overview of leaf epidermal micro-morphology with respect to water availability

This paper reports the result of a study undertaken with a view to documenting responses of leaf epidermal parameters of three economically important species of the family Asteraceae: Aspilia africana, Chromolaena odorata and Vernonia amygdalina from Nigeria to seasonal water stress. Obtained quantitative data showed a significant decrease (p < 0.05) in stomata density and index on the abaxial surface in Chromolaena odorata in dry conditions. The increased stomata densities and indices on the adaxial surfaces in Aspilia africana and Vernonia amygdalina in the wet season suggest that CO2 was more taken up. The reduction in stomata size (on both leaf surfaces in the three taxa) in the dry season indicated species' adaptations to dry conditions and reduction in stomatal conductance. Turgescent guard cell in the three species in the wet season indicated stomatal opening, which could, though, be a hormonal response to water availability since transpiration needed to be activated. The ability of Aspilia africana to reduce water loss and defend against herbivores greatly increased in plants that developed in dry conditions by possessing more multicellular trichomes in comparison to wet conditions, while in Vernonia amygdalina, the number increased during the wet season. Water stress had little or no effect on the micro-morphology of anticlinal walls and the shapes and arrangements of the epidermal cells in the three species. This study revealed that investigations into leaf epidermal micro-morphology might be a useful tool to elucidate the multiple mechanisms underlying leaf epidermal structure function in response to water availability.

Morphological and Stomata Characteristics of Trembesi (Samanea saman (Jacq.) Merr.) Leaves as Green Plants in Padang City, Indonesia

Greening along roads can be an alternative solution to overcome air pollution in urban areas. Direct contact of plants with pollutant particles in the air will affect the condition of plants, especially on leaves. Knowledge of morphological characteristics and stomata on leaves that have the potential to absorb pollutants is the basis for understanding plant responses to environmental changes. This research is descriptive research conducted in September-December 2021 with leaf samples taken in the area of ​​PT Semen Padang, Padang State University, and Andalas University forests. Data were analyzed by t test level of 5%. The results showed that the morphological characteristics of trembesi leaves in the PT Semen Padang and Padang State University areas had significant differences in the aspects of the number of leaflets, leaf length, leaf width, not significantly different in the length of the mother petiole and the number of leaf branch bones and the characteristics of the stomata did not show any difference which is evident from the aspect of stomata length and stomata density. The morphological characteristics of trembesi leaves in the Padang State University and Andalas University forests showed significant differences in the length of the mother petiole, the number of leaflets, and the number of leaf veins, there was no significant difference in leaf length and leaf width and showed a significant difference in the aspect of stomata length, but did not show a significant difference in terms of stomata density. Morphological characteristics of trembesi leaves in the PT Semen Padang area and Andalas University forest showed significant differences in the length of the mother petiole, number of leaflets, leaf length, leaf width, and number of leaf veins and did not show significant differences in terms of stomata length and stomata density.

Effect of Waterlogging Stress on Leaf Anatomical Structure and Ultrastructure of Phoebe sheareri Seedlings

Phoebe sheareri is an excellent roadside tree with a wide distribution range and high ornamental value. Excessive moisture can affect the external morphology, the microstructure, and the ultrastructure of the leaf. Little is known at present regarding the leaf structure of P. sheareri under waterlogging stress. In this paper, the external morphology of leaves, the microstructure of leaf epidermis, and the ultrastructure of mesophyll cells of P. sheareri seedlings under waterlogging stress and drainage were dynamically observed. Waterlogging stress contributed to the yellowing and wilting of P. sheareri seedling leaves, the gradual closing of leaf epidermal stomata, increasing density of leaf stomata, gradual loosening of the arrangement of leaf cell structure, and merging of leaf palisade tissue cells. Waterlogging stress forced the structure of the chloroplast membranes to blur, gradually causing swelling, and deformation, with plasmolysis occurring in severe cases. During waterlogging, the basal lamellae were disorganized, and the mitochondrial membrane structure was damaged. The damaged state of the leaves was not relieved after drainage. Waterlogging stress not only inhibited the growth of leaves, but also accelerated the closure of stomata, disordered the arrangement of palisade tissue and spongy tissue gradually, and damaged the internal organelles of mesophyll cells.