Morphological, Physiological, and Biochemical Responses of Zinnia to Drought Stress

Bedding plants in the nursery phase are often subject to drought stress because of the small volume of the containers and the hydraulic conductivity of organic substrates used. To analyse the morphological, physiological, and enzymatic responses of zinnia (Zinnia elegans L.) plants at different irrigation levels, four treatments were performed: irrigated at 100% (100% field capacity, FC); light deficit irrigation (75% FC), medium deficit irrigation (50% FC), and severe deficit irrigation (25% FC). The growth of zinnia was significantly influenced by drought stress treatments. Different morphological parameters (dry biomass, leaf number, root to shoot ratio (R/S)) were modified only in the more severe drought stress treatment (25% FC). The stomata density increased in 50% FC and 25% FC, while the stomata size was reduced in 25% FC. The net photosynthesis, stomatal conductance, and transpiration were reduced in 50% FC and 25% FC. The relative water content (RWC) was reduced in 25% FC. Severe drought stress (25% FC) increased proline content up to seven-fold. Catalase (CAT), peroxidase (GPX), and superoxide dismutase (SOD) activity significantly increased in 50% FC and 25% FC. Principal component analysis (PCA) showed that the morphological and physiological parameters were mostly associated with the 100% FC and 75% FC treatments of the biplot, whereas the stomata density, R/S ratio, and antioxidant enzymes (GPX, CAT) were associated with 50% FC, and proline and DPPH were associated with 25% FC, respectively.

Induced Genetic Variations in Stomatal Density and Size of Rice Strongly Affect Water-Use Efficiency, Drought Tolerance, and Responses to Abiotic Stresses

BackgroundRice (Oryza sativa) is one of the world’s most important crops and is especially important in Asia. Because irrigated rice consumes about 34–43% of the total water used for irrigation globally, increasing drought and global temperature will increase the risk of rice crop loss. However, rice is among the least efficient crops in terms of water use, whereby most of the uptaken water is used for transpirational cooling via stomatal pores on the leaf blades and sheaths. To increase the water-use efficiency of rice, alterations in stomatal density and size may help to reduce transpiration and thereby increase water-use efficiency (WUE). ResultsWe identified four stomatal model lines—with either high-density (HD) or low-density (LD) stomata and small-sized (SS) or big-sized (BS) stomata—from the Mutant Core Collection (MCC) of 216 mutants. Gas exchange analysis revealed that the stomatal model lines have similar photosynthetic assimilation (A) and chlorophyll fluorescence. With increasing CO2 concentration, A of all stomatal model lines was observed to respond similarly at 100–600 ppm CO2, but beyond this point, SS was more responsive to increasing CO2 concentration than the other stomatal model lines. HD had higher stomatal conductance (gs) and gsmax than the other stomatal model lines. In response to a mild heat at 30 °C, both SS and LD had higher canopy temperature than HD, BS, and JHN-wt as a result of heat retention. All stomatal model lines are also similar in their rhythmic stomatal responses to ten-minute dark/light transition cycles, except that initial stomata closure in SS was more rapid than in BS. The stomatal model lines did not show any significant differences in the response to short-term water stress. Long-term water stress had less impact on leaf drying, Fv/Fm, grain yield, and harvest index in LD and SS. In the field, all stomatal model lines and JHN-wt had similar WUE in the sufficient-water treatment. LD had the highest WUE and biomass/plant than any stomatal model lines in the long-term restricted-water treatment. ConclusionsTaken together, our results suggest that induced alterations in stomata density and size influence rice WUE and the responses to drought and heat stresses, providing further understanding of the roles of stomata density and size in related processes. The low-density and small stomata lines have high potential as genetic donors for improving WUE and drought in climate-ready rice.

Stomata Profile Comparisons in Abaxial and Adaxial Zones of Dendrobium aphyllum and Arachnis flos-aeris Leaves

Stomata play an essential role in transpiration and metabolism. Orchids are Crassulacean Acid Metabolism (CAM) plants which are generally succulent leaf type. Orchids have several types of stomata, depending on habitat and environmental parameters that affect them. This study aimed to compare the stomata, including the anatomical structure, activity, and density of the orchids Dendrobium aphyllum and Arachnis flos-aeris. The method used was printing the surface of the leaves using glue and observed with a microscope. Data obtained were analyzed with the help of Image raster 3.0 and MS. Excel. In the present study, the stomata of D. aphyllum and A. flos-aeris are characterized by anomocytic type. The highest stomata density was obtained on the abaxial part of D. aphyllum 09.00 am 1177.78 um2. The adaxial leaves of both species are classified as low, or no stomata are found at all. The distance between the stomata on the abaxial leaves of D. aphyllum and A. flos-aeris is denser than the leaves' adaxial side. Stomata activity in orchids is related to orchids' adaptation process to the environmental parameters of their habitat. Stomata activity affects the transpiration process and CO2 fixation in orchid CAM metabolism.

KARAKTERISASI STOMATA DAUN PEGAGAN (Centella asiatica (L.) Urban.) PADA KETINGGIAN WILAYAH BERBEDA DI PULAU AMBON

The purpose of this study was to determine the anatomical structure of pegagan leaves through stomata characterization at several different locations on Ambon Island. Survey method was used in this research. The sample was taken in nine villages were spread from lowlands to the highlands on Ambon Island. The procedure of semi-permanent preparations was done by whole mount method. Stomata characterization was done towards the stomata number, stomata density, and stomata index. The collected data were analyzed by descriptive analysis and performed in the form of table or figure. the research result shows that leaf with high stomata number was tend to high in stomata density and stomata index. Based on this research result, it could be conclude that there are no difference of stomatal structure of Pegagan leaves in all location were sample collected. The difference has shown by numbers, density, and stomatal index. The highest Numbers, density and stomatal index shown on Pegagan leaves in lowland, and the lowest that shown in this research on Pegagan leaves in highland

SISTEM PERBAIKAN EKOFISIOLOGI TANAMAN SENGON (Paraserianthes falcataria (L) Nielsen ) DI KECAMATAN WAGIR, 161 MALANG

Sengon plant (Paraserianthes falcataria (L) Nielsen) in Indonesia is one of the types of plants developed in the development of Community Forestry especially in Wagir District, Malang Regency. This study was conducted to analyze the effect of environmental conditions, especially temperature and humidity on stomata density and chlorophyll levels in the plant Sengon (Paraserianthes falcataria (L) Nielsen) and analyze the soil nutrient content under the Sengon stand (Paraserianthes falcataria (L) Nielsen) on plant physiology in Sukodadi Village, Wagir District, Malang Regency. The techniques used are field surveys, leaf sampling to measure physiological properties (stomata density and chlorophyll content), and soil sampling to measure soil chemical properties (macro nutrient content), as well as direct observations in the field to measure environmental factors (temperature and humidity). Analysis of the data used is multiple linear regression in SPSS to determine whether there is influence of temperature and humidity on the physiology of stomata and chlorophyll as well as descriptive analysis on soil factors. Research result is that temperature and humadity have an effect on chlorophyll. This support to possibility of temperature and humadity system in the region so that agreed crops will affect the concentration of chlorine.

PENGARUH FOTOAUTOTROFIK TERHADAP PERTUMBUHAN TUNAS KRISAN DALAM PROSES KULTUR IN VITRO SERTA PERBEDAAN STOMATA INVITRO DAN EXVITRO KRISAN

Chrysanthemum (Chrysanthemum indicum L.) is an ornamental plant that is included in an important contribution in the ornamental plant business. Related to chrysanthemum buds grown in vitro in culture tubes or bottles with a tightly closed to avoid bacterial and fungal contamination and to protect the humidity of the culture environment. However, this tight cap often affects the composition of the gas in a jar or bottle, which inhibits plant growth. The purpose of this study was to study the effect of photoautotrophic on the growth of chrysanthemum buds in the in vitro culture process and the differences in invitro and exvitro chrysanthemum stomata. This research was conducted in March 2016 to May 2016 in the Microtechnical Laboratory, IPB University. Research results obtained from research on the position given to research conducted on the number of roots, the number of books and the number of shoots. The influence of the environment of exvitro also significantly affects the number of stomata, stomata width and stomata density. Keywords :ex vitro, in vitro, photoautotrophic

Karakter Anatomi Daun sebagai Bentuk Adaptasi Tumbuhan Penyusun Zonasi Mangrove di Banggai Kepulauan, Provinsi Sulawesi Tengah

Mangrove is an essential ecosystem that are located in the transition area of fresh and sea water. Therefore, species that grow are typical species that are able to adapt to the saline environment. The aim of this research is to characterize leaf anatomical structure for every species that compose the communities found in each mangrove zonations, including their similarities and dissimilarities characteristic. Sampling of examined leaf was carried out in the mangrove areas of Peling Island and Bakalan Island by making plots in four sites of the mangrove ecosystem area. Methods for leaf anatomical preparations were carried out using the paraffin-tert-butanol and paradermal sections. Anatomical characters as an adaptation to saline habitat are found in all species of mangrove plants, including thick cuticle and epidermal cells, thick leaves and water-storage tissue (hypodermis). In addition, there is found the presence of cork warts and sclereid as characteristic of the genus Rhizophora. Based on quantitative character observations, the mesophyll (palisade to sponge) ratio range from 0.28 ± 0.04 μm to 1.19 ± 0.42 μm, leaf thickness ratio 289,41 ± 38,21 μm to 695,20 ± 97,50 μm and the highest stomata density is owned by Lumnitzera littorea

Influence of environment on the leaf morpho-anatomy and histochemical of the ayahuasca leaf: Populations cultivated in extra-Amazonian regions

Psychotria viridis Ruiz & Pav. (Rubiaceae) occurs naturally throughout the Amazon and it is traditionally used by indigenous communities, being incorporated into religious use in urban contexts over the last few decades. It is known and cultivated in many regions of South America for possessing valuable bioactive alkaloids. In this paper, we described P. viridis leaf morphology, anatomy and histochemistry from three populations cultivated in the southeastern Brazil, in order to identify possible adaptations to local environment and management. All plants presented terminal stipules and basic morpho-anatomical patterns of leaves, consistent with most species of the genus, as heterogeneous dorsiventral mesophyll, uniseriate epidermis, presents large cells with prominent vacuoles and druses. Unicellular non-glandular trichomes and multicellular starry trichomes were present in the primary and secondary veins. Amphi-hypostomatic leaf pattern, not yet described for the species, was common in all studied plants. Variation in the presence of domatia in the same population indicates that this structure cannot be used for taxonomic determination of P. viridis, as already described for other species of the genus. Presence of secretory ducts and reduction in stomata density and leaf area represent the main morpho-anatomic adaptations of plants from drier and warmer climates. Histochemical tests were positive for alkaloids, polysaccharides, proteins and phenolic compounds, being negative for starch only in plants subjected to water stress. We concluded that the morpho-anatomical and histochemical alterations found in the plants of this study resulted from seasonal water deficit adaptations and to maintain or attract mutualistic organisms.

Trade-offs and selection conflicts in hybrid poplars indicate the stomatal ratio as an important trait regulating disease resistance

ABSTRACTNatural selection can remove maladaptive genotypic variance from populations, leaving reduced phenotypic variation as a signal of its action. Hybrid populations offer a unique opportunity to study phenotypic variance before selection purifies it, as these populations can have increased genotypic and phenotypic variance than can reveal trade-offs and selection conflicts not visible, or visible to a lesser extent, in unadmixed populations. Here, we study the interactions between a fungal leaf rust disease (Melampsora medusae) and stomata and ecophysiology traits in a set of hybrid and unadmixed individuals formed by natural matings between Populus balsamifera, P. trichocarpa, P. angustifolia, and P. deltoides. Phenotypes were measured on cloned genotypes grown in a common garden and genotyped at 227K SNPs with GBS. Our analyses indicate hybridization decreases disease resistance and increases the variance of stomatal ratio (SR), or the ratio of upper leaf surface stomata density to total stomata density. Heritability of SR was high in admixed populations (H2 = 0.72) and covaries strongly with the proportion of P. balsamifera ancestry in a genome; thus, selection could effectively reduce disease by selecting for low values of stomatal ratio. However, selection conflicts present in some admixed populations may prevent adaptation to pathogens as a result of these populations being unable to occupy adaptive trait space along the growth-defense spectrum. These results suggest an important role for SR and stomatal patterning traits as a target of pathogen induced selection to achieve local fitness optima. Additionally, we demonstrate that hybridization is capable of generating, or magnifying maladaptive intermediate phenotypes to reveal trade-offs and selection conflicts.