Stomata Density Research Articles

Variation for Resistance to Alternaria tenuissima and Potential Structural Mechanism among Different Cultivars of Chrysanthemum morifolium

Black spot disease, caused by the necrotrophic fungus Alternaria tenuissima (Fr.) Wiltsh (A. tenuissima), is considered a highly destructive disease of Chrysanthemum (Chrysanthemum morifolium Ramat.). A set of 17 accessions of commercial chrysanthemum cultivars were evaluated for resistance to A. tenuissima by seedling artificial inoculation. It was found that the reaction of the accessions to artificial inoculation ranged from resistant to highly susceptible. Five varieties of chrysanthemum (‘Zhongshan Taogui’, ‘Jinba’, ‘Zhongshan Jinguan’, ‘Jinling Wanhuang’ and ‘Jinling Yangguang’) were resistant; two varieties of chrysanthemum (‘Zhongshan Xinggui’ and ‘Zhongshan Jinkui’) were moderately resistant; and others were susceptible to various degrees, four varieties of chrysanthemum (‘Zhongshan Zihe’, ‘Zhongshan Jiuhong’, ‘Zaoyihong’ and ‘Jinling Jiaohuang’) were highly susceptible, especially. Some leaf morphological features of two resistant and two highly susceptible cultivars were further researched. Trichome density, length, height, gland size and stomata density were found to be associated with plant passive resistance. Resistant varieties that were identified in present study will be promising germplasm for exploitation of breeding programmes aimed at developing A. tenuissima-resistant cultivars and increasing genetic diversity.

Stomatal traits as a determinant of superior salinity tolerance in wild barley

Wild barley Hordeum spontaneum (WB) is the progenitor of a cultivated barley Hordeum vulgare (CB). Understanding efficient mechanisms evolved by WB to cope with abiotic stresses may open prospects of transferring these promising traits to the high yielding CB genotypes. This study aimed to investigate the strategies that WB plants utilise in regard to the control of stomatal operation and ionic homeostasis to deal with salinity stress, one of the major threats to the global food security. Twenty-six genotypes of WB and CB were grown under glasshouse conditions and exposed to 300 mM NaCl salinity treatment for 5 weeks followed by their comprehensive physiological assessment. WB had higher relative biomass than CB when exposed to salinity stress. Under saline conditions, WB plants were able to keep constant stomatal density (SD) while SD significantly decreased in CB. The higher SD in WB also resulted in a higher stomatal conductance (gs) under saline conditions, with gs reduction being 51% and 72% in WB and CB, respectively. Furthermore, WB showed faster stomatal response to light, indicating their better ability to adapt to changing environmental conditions. Experiments with isolated epidermal strips indicated that CB genotypes have the higher stomatal aperture when incubated in 80 mM KCl solution, and its aperture declined when KCl was substituted by NaCl. On the contrary, WB genotype had the highest stomatal aperture being exposed to 80 mM NaCl suggesting that WB plants may use Na+ instead of K+ for stomata movements. Overall, our data suggest that CB employ a stress-escaping strategy by reducing stomata density, to conserve water, when grown under salinity conditions. WB, on a contrary, is capable of maintaining relatively constant stomata density, faster stomatal movement and higher gs under saline conditions.

Common gardens in teosintes reveal the establishment of a syndrome of adaptation to altitude.

In plants, local adaptation across species range is frequent. Yet, much has to be discovered on its environmental drivers, the underlying functional traits and their molecular determinants. Genome scans are popular to uncover outlier loci potentially involved in the genetic architecture of local adaptation, however links between outliers and phenotypic variation are rarely addressed. Here we focused on adaptation of teosinte populations along two elevation gradients in Mexico that display continuous environmental changes at a short geographical scale. We used two common gardens, and phenotyped 18 traits in 1664 plants from 11 populations of annual teosintes. In parallel, we genotyped these plants for 38 microsatellite markers as well as for 171 outlier single nucleotide polymorphisms (SNPs) that displayed excess of allele differentiation between pairs of lowland and highland populations and/or correlation with environmental variables. Our results revealed that phenotypic differentiation at 10 out of the 18 traits was driven by local selection. Trait covariation along the elevation gradient indicated that adaptation to altitude results from the assembly of multiple co-adapted traits into a complex syndrome: as elevation increases, plants flower earlier, produce less tillers, display lower stomata density and carry larger, longer and heavier grains. The proportion of outlier SNPs associating with phenotypic variation, however, largely depended on whether we considered a neutral structure with 5 genetic groups (73.7%) or 11 populations (13.5%), indicating that population stratification greatly affected our results. Finally, chromosomal inversions were enriched for both SNPs whose allele frequencies shifted along elevation as well as phenotypically-associated SNPs. Altogether, our results are consistent with the establishment of an altitudinal syndrome promoted by local selective forces in teosinte populations in spite of detectable gene flow. Because elevation mimics climate change through space, SNPs that we found underlying phenotypic variation at adaptive traits may be relevant for future maize breeding.

Epidermal structures of leaves in some Mentha х piperita L. varieties in connection with they productivity

Relevance. It is known that peppermint (Mentha х piperita L.) is characterized by significant polymorphism, due to both genetic factors and growing conditions. Cultivated varieties and populations are distinguished by their economically significant characteristics, such as yield, winter hardiness, resistance to diseases, the content and composition of essential oil. Identification of new highly productive varieties and populations of Mentha x piperita L., distinguished by high productivity of essential oil in the Non-chernozem zone of the Russian Federation, as well as identification of morphological features characteristic of highly productive varieties, remains relevant.Methods. The object of the study was plants of 8 varieties of 2 year old plants and samples of Mentha x piperita L. from the collection of the SI Botanical Garden Rostovtsev RGAU-Moscow Agricultural Academy named after K.A. Timiryazev and from the collection of the Botanical Garden of All-Russian Institute of Medicinal and Aromatic Plants (VILAR), were used as the object of the study. Peppermint leaves (FS.2.5.0029.15 Peppermint leaves) and essential oil (GOST R 53593-2009) are used as herbal medicinal products. Microscopy used Primo Star Carl Zeiss light microscopes and LOMO MIKMED-1. Quantitative determination of the essential oil was carried out by distillation with water vapor, followed by measuring the volume of the resulting oil (GF RF XIV). The oil content was expressed in volumetric-weight percent in terms of dry raw materials.Results. As a result of a comparative study of the epidermal structures of the leaves of plants of 8 varieties of Mentha х piperita L., the density of stomata, the type of stomatal apparatus, density of location and length of multicellular trichomes, density and diameter of essential oil glands, and content of essential oil were determined. The variety specificity and variation of these indices are noted over a wide range, which is explained by the significant intraspecific variability characteristic of the genus Mint (Mentha L.). The most promising varieties of essential oil content were identified.

APLIKASI BAKTERI PELARUT FOSFAT DAN ROCK PHOSPHATE TERHADAP KARAKTERISTIK FISIOLOGI TANAMAN TOMAT (Solanum lycopersicum L.)

Phosphorus (P) is one of the essential nutrients that functions is metabolism in plant. Based on these functions, it indicates that nutrient P has an important role for plant growth and production. However, its availability in soil is very low, which is less than 0.01% of the total P. Therefore, the availability of P nutrients in the soil needs to be increased by increasing the activity of soil microorganisms through the use of phosphate solubilization bacteria. This research is aimed to show the changes in the physiological characteristics of tomato plants through the application of phosphate solubilization bacteria and rock phosphate. Experiment using factorial randomized block design (RBD) which consisted of 2 factors with 2 consultation levels on the first factor (phosphate solubilization bacteria) and 4 levels on the second factor (rock phosphate), and it consist of 8 combinationed of phosphate solubilization bacteria and rock phosphate with 3 replicated. The results showed that the combination treatment of phosphate solubilization bacteria and rock phosphate affected the physiological characteristics of tomato plants, especially on the variables of stomata density, leaf chlorophyll, plant height, plant dry weight, fruit weight and plant P-tissue content in the vegetative final phase. The recommendation of an efficient fertilizer combination to improve physiological characteristics and high yields is use the phosphate solubilization bacteria and rock phosphate 0.69 grams Keywords: phosphate solubilization bacteria, physiological characteristic, rock phosphate

The Evolution of Functional Traits in Plants: Is the Giant Still Sleeping?

The Evolution of Functional Traits in Plants: Is the Giant Still Sleeping?

Karakteristik Morfologi dan Anatomi Jahe (Zingiber Officinale) Berdasarkan Perbedaan Ketinggian Tempat

The purpose of this study was to determine the differences in the morphology and anatomy of ginger plants based on differences in altitude, and to make a booklet resulting from the morphological and anatomical characteristics of ginger for morphology and plant anatomy courses. This research method is a qualitative research method. Data collection techniques in this study through observation, interviews, characterization techniques, document review, and questionnaires or questionnaires. Data analysis techniques with quantitative descriptive and descriptive analysis. The results of the study showed that there were differences in the morphological and anatomical characteristics of ginger based on differences in the height of the place. Ginger in Selupu Rejang District has a high stomata density. Ginger is more suitable for planting in the lowlands with high temperatures, low humidity. The compilation and manufacture of morphology and plant anatomy course booklets were declared valid with very decent qualifications with a percentage of 86.2%. Conclusion, there are differences in the morphological and anatomical characteristics of the ginger plant based on the height of the place, while the booklets that are made have proper and valid qualifications to be used as material for plant morphology and anatomy courses.
 Keywords: anatomy, ginger, characteristics, morphology

Identifikasi Awal Perbedaan Karakter Morfofisiologi Antar Empat Kultivar Kopi Arabika

<em>Arabica coffee is a perennial crop hence it has a long selection cycle. Therefore, efforts to shorten the selection process is necessary, such as at seedling stage. This study aims to identify morpho-physiological characters variability among Arabica coffee cultivars at seedling stage. The experiment was conducted at Pakuwon Experimental Garden of Indonesian Industrial and Beverage Crops Research Institute, Sukabumi, from January to October 2017. Seeds collected from open pollinated trees of four arabica coffee cultivars (Ateng Super, P88, Gayo 1, and Gayo 2) were then sown on seedbed and newly-emerged cotyledonous seedlings were transferred immediately into polyethylene bag (polybag). Seedlings were arranged in randomized complete block with 5 replications, each consisted of 10 seedlings of each cultivar. Morpho-physiological characters observed and analyzed were shoot (plant height, lateral shoot formation, number of internodes, internode length, stem diameter, shoot’s dry weight); leaves (number of leaves, leaf length, leaf width, L/W ratio, leaf area, stomata density , chlorophyll content); and root (root length, number of primary roots, root volume, root’s dry weight, root/shoot ratio). The result showed value of genetic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), and broad sense heritability (h<sup>2</sup><sub>bs</sub>) of plant height characters are classified as high, each of which is 21.66%; 23.66%; and 0.84, respectively. The characters of the stem length and leaf width showed high h<sup>2</sup><sub>bs</sub> value (0.97 and 0.67 respectively), while the KKG and KKF values were classified as moderate (19.60% and 19.88%, respectively and 10.71% and 13.10%, respectively). Those three characters could be utilized as distincitive markers of the four Arabica coffee cultivars.</em>

Enhanced thebaine and noscapine production and modulated gene expression of tyrosine/dopa decarboxylase and salutaridinol 7-O-acetyltransferase genes in induced autotetraploid seedlings of Papaver bracteatum Lindl

Papaver bracteatum, belonging to Papaveraceae, is considered to be a primary ingredient in the production of codeine and anti-drug drugs (e.g., naloxone and Naltrexone) without the involvement of morphine. For polyploidy induction, papaver seedlings were treated with various colchicine concentrations (0, 0.05, 0.1, 0.2 and 0.5% w/v) in three time durations (24, 48 and 72 h). The effects of polyploidy induction on morphological, physiological, alkaloid production and gene expression levels in the pathway of benzylisoquinoline alkaloids were analyzed. High rates of seedling survival were observed at lower colchicine concentrations (0.05 and 0.1% w/v) versus higher concentrations (0.2 and 0.5% w/v). The best polyploidy treatment to induce P. bracteatum shoot tips was observed in plants treated with 0.2% colchicine for 72 h. P. bracteatum-induced tetraploids showed higher stomata and an increase in leaf area (mm2), chlorophyll (a, b and total) and a decrease in stomata density, leaf length (cm) and petiole length. Flow cytometry and chromosome counting analysis revealed that chromosome number was 2n = 2x = 14 in diploid plants and 2n = 4x = 28 in tetraploid plants. Gene expression analysis through semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) showed that the transcription level of sat and tydc genes of the benzylisoquinoline biosynthesis pathway was enhanced in tetraploid plants. The tetraploid plants of P. bracteatum also showed 5.86 and 30.55 times higher thebaine and noscapine contents than the diploid plants, respectively. Regarding the higher commercial value of thebaine and noscapine, tetraploids can efficiently be used to improve the thebaine and noscapine production of P. bracteatum.

Foliar Micromorphology and Histochemical Localization of Specific Metabolites in the Leaves of Celosia argentea L.

Celosia argentea is an essential vegetable that is cultivated in the western part of Africa. This species has a growing reputation for its role in alleviating nutritional challenges and has found great application as herb of therapeutic importance in many regions of the world. This study investigated the foliar micromorphology and the histochemistry of Celosia argentea. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectrometry and staining agents were used to evaluate the micromorphology of the plant. The result revealed sunken amphistomatic stomata distribution on both surfaces of the leaf. Anomocytic and anisocytic stomata complexes were also observed on both epidermal surfaces. A definitive protuberance was observed on the polar end of the adaxial stomata. Stomata apparatus was ellipsoidal with a mean length of 19.60 ± 0.56 µm, while the mean stomata densities on the adaxial and abaxial surfaces were 83.5 ± 2.12 mm‑2 and 194.18 ± 3.70 mm‑2 respectively. Trichomes (with a length of 100.94 ± 9.44 µm) were sparsely distributed on both surfaces; glandular trichomes were observed only on the abaxial surface. The EDX spectrometry revealed the presence of iron, oxygen, sodium, calcium, potassium and sulphur as the major elements on the leaf, while histochemical tests revealed the presence of polyphenols, starch and lipids. Our results could be used to support and validate the information database on the anatomy of Celosia argentea.
 
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 In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 4, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue.
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Stomatal openings on boxwood leaves yield entry portals for leaf infection by Calonectria pseudonaviculata

The distribution, density, and size of leaf stomata for eight boxwood taxa were investigated using both light and electron microscopy. Stomata, the pores that facilitate gaseous exchange during photosynthesis, were primarily located on the abaxial (lower) epidermis of boxwood leaves with minimal distribution on or along the central vein of the adaxial (upper) surface. Inoculation of boxwood leaves with Calonectria pseudonaviculata at different leaf sites showed that infection occurred only in areas where stomata were present. Scanning and transmission electron microscopic examination of the inoculated leaves also confirmed that the fungal pathogen gains leaf entry through stomatal openings and not by direct penetration of the cuticle. Among the eight boxwood taxa examined, stomatal densities ranged from 116 ± 15 (B. sinica ‘NaNa’) to 326 ± 21 (B. harlandii) stomata per mm2; stomatal size ranged from 500 ± 84 um2 (B. harlandii) to 1052 ± 117 um2 (B. sinica ‘NaNa’); and stomatal area per leaf (density × size) ranged from 88.63 mm2 (‘Justin Brouwers’) to 154.3 mm2 (B. harlandii). No relationship between stomatal density or size and infection rate was observed; relationships between infection rate and stomatal location and stomatal area on the abaxial surface were demonstrated.

Ecological and biological features of adaptation of deciduous plants to chemical stress

In the urbanized environment, young plants lack moisture due to the limited space. This violates photosynthesis and respiration. To normalize respiration, the plant reduces excessive evaporation and evens out the water balance showing signs of xeromorphy. For the human environment, decorative and appearance of greenery are crucial. The purpose of the article is to study adaptive abilities of deciduous plants when using glyphosate-based herbicidal preparations, 2, 4-D, dicamba, triasulfuron, and clopyralid. Anatomical and morphological changes at the cellular and organismic levels in young Tilia cordata Mill plants were identified: the size and density of stomata; frequency of stop cells of stomata; plant height; the number of shoots. The use of glyphosate, 2, 4-D, dicamba, triasulfuron, clopyralid stimulated the height of shoots and increased the frequency of occurrence of guard cells with a length “0.15-0.19” mm. When using herbicides as a factor of chemical stress, the number of stomata per 1 mm2 of the leaf surface increased. Ecological and biological plasticity of Tilia cordata Mill under environmental pollution (chemical stress) was identified. It is useful for directed formation of xeromorphic signs in young plants and further planting in urbanized conditions.

Transcriptional foliar profile of the C3-CAM bromeliad Guzmania monostachia.

Guzmania monostachia is an epiphytic tank bromeliad that displays the inducible CAM photosynthesis under stressful conditions and had the highest stomata density in the leaf apex, while the base portion has the highest density of trichomes, which are specialized structures used to acquire water and nutrients from the tank solution. In order to correlate the genetic factors behind these morpho-physiological characteristics along the leaf blade of G. monostachia, a comparative transcriptome analysis was performed to identify the functional enriched pathways and unigenes that could play a role in the apical, middle and basal leaf portions. A total of 653 million reads were used for de novo transcriptome assembly, resulting in 48,051 annotated unigenes. Analysis of differentially expressed genes (DEGs) among distinct leaf regions revealed that 806 DEGs were upregulated in the apex compared to the middle portion, while 9685 DEGs were upregulated in the apex and 9784 DEGs were upregulated in the middle portions compared to the base. Our outcomes correlated some DEGs and identified unigenes with their physiological functions, mainly suggesting that the leaf apex was related to the regulation of stomatal movement, production of chlorophyll, cellular response to stress, and H2O2 catabolic process. In contrast, the middle portion showed DEGs associated with the transport of amino acids. Furthermore, DEGs from the leaf base were mainly correlated with responses to nutrients and nitrogen compounds, regulation of potassium ion import, response to water deprivation, and trichome branching, indicating that, at least in part, this leaf portion can replace some of the root functions of terrestrial plants. Therefore, possibly candidate unigenes and enriched pathways presented here could be prospected in future experimental work, opening new possibilities to bioengineer non-inducible CAM plants and/or improve the fertilization use efficiency by increasing leaf nutrient acquisition of crop plants.

Foliar plasticity related to gradients of heat and drought stress across crown orientations in three Mediterranean Quercus species.

Studies on plasticity at the level of a single individual plant provide indispensable information to predict leaf responses to climate change, because they allow better identification of the environmental factors that determine differences in leaf traits in the absence of genetic differences. Most of these studies have focused on the responses of leaf traits to variations in the light environment along vertical gradients, thus paying less attention to possible differences in the intensity of water stress among canopy orientations. In this paper, we analyzed the differences in leaf traits traditionally associated with changes in the intensity of water stress between east and west crown orientations in three Quercus species. The leaves facing west experienced similar solar radiation levels but higher maximum temperatures and lower daily minimum water potentials than those of the east orientation. In response to these differences, the leaves of the west orientation showed smaller size and less chlorophyll concentration, higher percentage of palisade tissue and higher density of stomata and trichomes. These responses would confirm the role of such traits in the tolerance to water stress and control of water losses by transpiration. For all traits, the species with the longest leaf life span exhibited the greatest plasticity between orientations. By contrast, no differences between canopy positions were observed for leaf thickness, leaf mass per unit area and venation patterns.

Suitability of foliage plants for indoor decoration based on CO<sub>2</sub> emission and absorption rate and stomata density

Use of foliage plants for indoor decoration is pursuing tradition in several cultures. With contemporary living patterns, frequent replacement of indoor plants has become impractical. Therefore, this experiment was conducted to identify indoor plants with low carbon dioxide (CO2) emission or CO2 absorption ability in nights to be kept continuously indoors. Five common indoor plants (Cryptanthus sp., Dieffenbachia seguine, Dracaena sanderiana, Sansevieria trifasciata and Zamioculcas zamiifolia) were placed separately in 1000 L airtight chambers for 12 h in the dark. The CO2 level in each chamber was measured before and after the experiment and the difference was calculated. The stomatal count of both adaxial and abaxial surfaces was taken in each plant type to determine the relationship between CO2 emission/absorption efficiency and stomatal density of tested ornamental species. From the test plant species, D. seguine, D. sanderiana and Z. zamiifolia, showed positive CO2 equilibrium in the chambers and the CO2 increments were 0.16 ppm cm-2, 0.39 ppm cm-2 and 0.18 ppm cm-2 of leaf area, respectively. Both Cryptanthus sp. and S. trifasciata showed negative CO2 equilibrium at around -0.20 ppm cm-2 of leaf area. Sansevieria trifasciata and D. sanderiana possessed stomata in both adaxial and abaxial surfaces, while stomatal number in adaxial surface of other three test plant species was negligible. The average number of stomata Cryptanthus sp. was 5.56x10⁴ cm⁻2, D. seguine 5.03x10⁴ cm⁻2, D. sanderiana 9.05x10⁴ cm⁻2, S. trifasciata 5.25x10⁴ cm⁻2 and Z. zamiifolia 3.51x10⁴ cm⁻2. Stomata in Cryptanthus sp. and S. trifasciata close during day time and open at night. Present study concludes that potted Cryptanthus sp. and S. trifasciata (plants with CAM photosynthesis pathway) used for indoor decoration absorb CO2 during the night, and hence, are safe to keep indoors during day and night.

DcDREB1A, a DREB-binding transcription factor from Daucus carota, enhances drought tolerance in transgenic Arabidopsis thaliana and modulates lignin levels by regulating lignin-biosynthesis-related genes

Carrot (Daucus carota L.) is an important root vegetable of Apiaceae, whose growth and production are negatively affected by abiotic stress. Dehydration-responsive element-binding protein (DREB) transcription factors usually play significant roles in the responses of plants to abiotic stress. However, knowledge on the functions of DREB transcription factors in carrots remains limited. In this study, the functional characterization of a DREB gene, DcDREB1A, cloned from carrot was reported. DcDREB1A was found to be a nuclear protein that can specifically bind to DRE element. Under drought treatment, DcDREB1A overexpression in transgenic plants resulted in increased superoxide dismutase (SOD) and peroxidase (POD) activities and decreased size of stomata apertures. Moreover, transgenic plants accumulated an increased amount of lignin and exhibited higher expression levels of lignin biosynthesis gene compared with wild-type plants. Overall, our findings revealed that DcDREB1A was involved in the regulation of plant tolerance to drought. DcDREB1A served as a positive regulator by regulating the activities of reactive oxygen species (ROS)-scavenging enzymes (SOD and POD) to maintain ROS homeostasis in cells, reducing stomata apertures and density, modulating lignin synthesis to control water loss, and inducing the expression of stress-responsive genes.

Interaction between extreme weather events and mega‐dams increases tree mortality and alters functional status of Amazonian forests

Abstract Forest responses to changes in drought frequency is a critical matter for the future of Amazon forests under climate change, but equally important is the much less studied response to large floods, which may also increase tree mortality and change forest functionality. Further, forest vulnerability to flood is being exacerbated by large hydroelectric dams on Amazon rivers that put upland environments not adapted to flood at unique risk. To address this critical knowledge gap, we evaluated the effects of the extreme 2014 rainfall coupled with the newly constructed Jirau hydroelectric dam on tree survival and forest functionality, in the upper Madeira River basin. We used surveys of campinarana white‐sand forests (stems >1 cm in seven 1 ha plots) conducted before and after the extreme flood to test trait‐based ecological theory predictions of the impact of flood on overall community function. We found that flooding increased mortality by nearly five‐fold (from 3.2% to 15.1%), mostly in smaller trees. This large mortality induced significant and consistent shifts in community function, towards species with conservative life strategies: direct comparison of trait differences between surviving and dying trees showed that survivors had smaller, high density stomata, and higher leaf dry matter content, wood density and root tissue density (RTD). Size and density of stomata and RTD were the most important predictors of species mortality rates. Synthesis and applications. Although focused on a single event in one type of forest, this work highlights the general importance, and need for further study, of interaction between climate change and mega‐dams in Amazon forests. In particular, we expect that continued expansion of hydroelectric dams in Amazonia will likely intensify the impact of large floods on forests made newly vulnerable by these dams, with substantial effect on future forest functionality in expanded floodplain areas across the Basin. Hence, these interaction analyses should be required in the Brazilian legal instruments such as the environmental impact assessments and its accompanying Environmental Impacts Reports for large infrastructure projects in Amazon.

Morpho-physiological and Yield Responses of Sweet Potato (Ipomoea batatas (L.) Lam.) Genotypes to Frequency of Irrigation under Greenhouse Condition

Introduction: The sweet potato (Ipomoea batatas Lam.), is one of the root and tuber crops grown from low land to high land region of Ethiopia. However, its productivity depends on adaptability and tolerance to different environmental stresses and the capacity of the crop to enhance water use efficiency under moisture stress conditions. The objective of this study was to evaluate impact of irrigation interval on morpho-physiological characteristics of sweet potato varieties.
 Methodology: The trial was a 3 x 2 factorial arrangement in CRD design consisting: three irrigation intervals (daily-control), four days and seven days interval) combined with two sweet potato genotypes (Hawassa-83 and Kulfo) with three replications.
 Results: The morpho-physiological indicators, morphological traits, water use efficiency (WUE), Relative leaf water content (RLWC), leaf gas exchange, stomata density, and tuber yield were evaluated. The result indicated that morphological traits were significantly (P≤0.05) responded to genotype and irrigation frequencies. As compared to daily irrigation, an extended watering interval to seven days irrigation interval significantly reduced leaf number, vine length, branch number and internode length by 55.42, 19.83 cm, 2.17 and 0.35 cm, respectively. Stomata density was strongly responded to genotypes than effect of irrigation frequency. Genotype Hawassa-83 had approximately 2.0 more stomata per mm2 than genotype Kulfo regardless to irrigation frequency. The interaction effect between genotype and irrigation frequency revealed significant influence on photosynthesis and transpiration rate. The rate of assimilate accumulation was significantly reduced (by 9.97

The effect of elevational gradient on alpine gingers (Roscoea alpina and R. purpurea) in the Himalayas.

There is currently enormous interest in how morphological and physiological responses of herbaceous plants may be affected by changing elevational gradient. Mountain regions provide an excellent opportunity to understand how closely related species may adapt to the conditions that rapidly change with elevation. We investigated the morphological and physiological responses of two Himalayan alpine gingers (Roscoea alpina and R. purpurea) along two different vertical transects of 400 m, R. purpurea between 2,174–2,574 m a.s.l and R. alpina between 2,675–3,079 m a.s.l. We measured the variables of plant height, leaf length, leaf area, specific leaf area, and stomata density at five plots, along the vertical transect at an elevational gap of ca. 100 m. Results revealed that with increased elevation plant height, and leaf area decreased while stomata density increased, whereas changes in specific leaf area, were not correlated with the elevation. Our results reveal that these alpine gingers undergo local adaptation by modifying their plant height, leaf area and stomata density in response to the varying selection pressure associated with the elevational gradient. Thus, the findings of this research provide valuable information on how a narrow range of elevational gradient affects the herbaceous plants at the alpine habitat of the Himalayas.

Plant resistance to leaves and their effects on paddy rice production in Kutai Barat District, East Kalimantan Province, Indonesia

Abstract. Akhsan N, Sopialena, Fahrizal. 2019. Plant resistance to leaves and their effects on paddy rice production in Kutai Barat District, East Kalimantan Province, Indonesia. Asian J Agric 3: 41-46. This study was aimed to evaluate the effect of fertilizer application on the resistance of lowland commercial rice cultivars (Oryza sativa L.) against leaf spot diseases in Kutai Barat District, East Kalimantan Timur, Indonesia and to determine the factors influencing the resistance. A field experiment was conducted in rice fields within Long Iram and Linggang Bigung Sub-districts, West Kutai District and the disease identification was performed at the Laboratory of Pests and Diseases, Faculty of Agriculture, Mulawarman University. The field experiment was designed in a split-plot design arranged in a Randomized Block Design (RBD) using four replications. The main plot was fertilizer application (P) consisting of two fertilizer application treatments, i.e., 200 kg.ha-1 Urea (p1), and 200 kg.ha-1 Urea + 200 kg.ha-1 NPK (p2). The sub-plots were varieties (V) consisting of three varieties, i.e., Ciherang (v1), Mekongga (v2) and Inpari 6 (v3). The disease identification was performed by identification of leaf spot disease, isolated from the sample plants using morphological observation under a microscope. The number and density of stomata, intensity of leaf disease infection, and yield of the rice were observed. The humidity was also measured at the time of observation of leaf spot disease intensity. The results showed that different fertilizer treatments did not affect the leaf spot disease intensity, but the varieties affected the disease intensity at 7, 14, 21.35 and 49 days after planting. The number of stomata of Ciherang, Mekongga and Inpari 6 varieties was 230,182 and 236 stomata/mm2, respectively. Ciherang variety was more resistant against the leaf spot disease compared to other varieties. Stomatal density does not always affect the intensity of leaf spot disease in lowland rice. There was a correlation between air humidity and the intensity of leaf disease infection. The interaction between fertilization and varieties was significant for the rice yield and the highest yield was obtained by Ciherang variety fertilized with 200 kg.ha-1 Urea + 200 kg ha-1 NPK about 3.58 Mg.ha-1 (grain wet weight).In conclusion, Fertilizer application does not affect the leaf spot disease infection and Ciherang variety is the most resistant plant against leaf spot disease compared to Mekongga and Impari 6 varieties.