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Search Results: 1 - 10 of 12735 matches for " drought resistance "
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Ultrasound on Seedling Growth of Wheat under Drought Stress Effects  [PDF]
Haiyan Ran, Liyan Yang, Yanling Cao
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.67064
Abstract: This study used different intensity ultrasound treatments, wheat seedlings in the germination energy, germination rate, growth potential, root length, and number of lateral roots optimal radiation dose selection. Studied under drought stress were the optimal dose of radiation treatment of wheat seedling leaf relative water content (RWC), protein content, Methane Dicarboxylic Aldehyde (MDA) content, relative conductivity, Superoxide dismutase (SOD) activity, and the impact of amylase activity. Studies have shown that after ultrasonic treatment enhanced drought resistance of wheat seedlings, alleviate drought stress on wheat seedling injury to 65 W 15 min ultrasonic treatment works best.
Research progress in physiological and molecular biology mechanism of drought resistance in rice  [PDF]
Qiang Chen, Siyuan Tao, Xiaohua Bi, Xin Xu, Lanlan Wang, Xuemei Li
American Journal of Molecular Biology (AJMB) , 2013, DOI: 10.4236/ajmb.2013.32014
Abstract:

Rice is one of the most important crops, providing staple food for about half population of the world. Drought stress affects plant growth and development seriously. This article reviewed the research progress of the physiological and molecular biology mechanism including osmotic adjustment, scavenging oxidative radicals, endogenous hormones, drought-resistance genes and epigenetic modification, it may be afford interrelated reference for increasing rice drought resistance and breeding drought resistance rice varieties.

Correlation Between Drought Resistance Indices and Cotton Yield in Stress and Non Stress Conditions
M.R. Zangi
Asian Journal of Plant Sciences , 2005,
Abstract: In this research, then varieties of cotton (Gossypium hirsutum L.) were studied in two separate Randomized Complete Block Design (RCBD) field experiments. One of the experiments was irrigated and the other one not. The correlation between the yields in the two environments was negligible. This would imply the difficulties of yield improvement in irrigated experiments for high yield performance in dry condition. Based on the most of the estimated resistance indices except for Tol, Sahel, Siokra and Naraberay were the best varieties. For the index of drought tolerance, HAR, B-557, Backtegan, Crema and Varamin varieties were remarkable.
Comparative estimate of resistance to drought fro selected karstic aquifers in Bulgaria
Orehova Tatiana
International Journal of Speleology , 2004,
Abstract: Effective management of water resources requires adequate knowledge of groundwater system including the influence of climate variability and climate change. The drought of 1982-1994 in Bulgaria has led to important decrease of springflow and lowering of water levels. Therefore, groundwater demonstrated its vulnerability to drought. The purpose of this paper is to determine relative resistance of selected aquifers in Bulgaria to a prolonged decrease of recharge to groundwater. The drought resistance indicator has been defined for some karstic aquifers based on the method proposed in report of BRGM. The data from National Hydrogeological Network located in the National Institute of Meteorology and Hydrology were processed. For the aim of this study, time-series of discharge for karstic springs were used. Stations with significant impact of human activity on groundwater were eliminated. The results show that most of studied aquifers in Bulgaria have moderate and weak resistance to the drought. They are vulnerable to droughts and need good management for effective use of groundwater resources.
Genetic Engineering Peanut for Higher Drought- and Salt-Tolerance  [PDF]
Li Sun, Rongbin Hu, Guoxin Shen, Hong Zhang
Food and Nutrition Sciences (FNS) , 2013, DOI: 10.4236/fns.2013.46A001
Abstract: Peanut (Arachis hypogaea L.) is one of the major oilseed crops, mainly grown in tropical and sub-tropical regions of the world. It is also rich in proteins, vitamins and ions, therefore it constitutes an important portion of food nutrition for people in these regions. The production of peanut is being threatened by the changing environments as the major peanut producing counties such as China, India, and USA are facing severe water shortage for peanut irrigation. The yield and quality of peanut are negatively affected by drought and salinity. Making peanut more droughtand salt-tolerant will likely sustain peanut production in countries where water shortage or saline soil are already problems. Efforts were made to genetically engineer peanut for higher tolerance to drought and salt. Analysis of these transgenic peanut plants indicated that the agronomic traits such as peanut yields were the same between wild-type and transgenic peanut plants under normal growth conditions, yet the yields of transgenic peanut plants were much higher than wild-type peanut plant under reduced irrigation conditions. Other traits such as protein content and fatty acid compositions in the seeds of transgenic peanut plants were not altered under both normal and drought conditions, indicating that the genetic manipulation of peanut for stress tolerance did not affect chemical compositions of peanut seeds in transgenic peanut plants, only increased seed yields under stress conditions.
Effects of Continuous Vertical Soil Pores on Root and Shoot Growth of Winter Wheat: A Microcosm Study  [PDF]
Tim Dresemann, Miriam Athmann, Lukas Heringer, Timo Kautz
Agricultural Sciences (AS) , 2018, DOI: 10.4236/as.2018.96053
Abstract: Round shaped, continuous vertical pores (CVPs) in the soil are typically created by roots and earthworms. CVPs with diameters > 2 mm are abundant in many agricultural soils. We hypothesized that potential effects of CVPs on shoot growth of winter wheat (Triticum aestivum L.) increase with: 1) decreasing availability of water and 2) decreasing availability of nutrients in the topsoil. We conducted a microcosm experiment with different irrigation regimes (Irr+/Irr-) and P concentrations (P+/P-), with or without artificially created continuous vertical pores (CVP+/CVP-). Winter wheat was cultivated for 16 weeks. In the bulk soil, presence of CVPs resulted in decreased root length in 20 - 40 cm but increased root length in 40 - 60 cm soil depth. In general, total root length of winter wheat in 20 - 60 cm soil depth was higher when CVPs were present or when P concentrations in the topsoil were elevated. Presence of CVPs generally had a positive effect on shoot dry matter and N uptake of wheat. In columns with high phosphorous concentrations but low soil moisture in the topsoil, presence of CVPs increased shoot dry matter by 66%; in contrast, the beneficial effect of CVPs on shoot dry matter was only 39% in columns with high nutrient concentrations and high soil moisture in the topsoil. In total numbers, however, the effect of CVPs on P uptake into the shoot was more pronounced when P concentrations in the topsoil were elevated. We conclude that CVPs can promote the exploration of the solid soil phase by high root-length densities, but adequate nutrient supply in the topsoil is essential.
Research advances on drought resistance mechanism of plant species in arid zones of China

YaJuan Zhu,Lei Li,ZhiQing Jia,

寒旱区科学 , 2011,
Abstract:
FUNCTION OF HYDRAULIC AND CHEMICAL WATER STRESS SIGNALIZATION IN EVALUATION OF DROUGHT RESISTANCE OF JUVENILE PLANTS
K OL?OVSKá,M BRESTI?
Journal of Central European Agriculture , 2002,
Abstract: In laboratory hydroponic experiments with spring barley genotypes the juvenile plants with 5 leaves were tested for their physiological responses to osmotic stress evoked by blocking the water uptake in roots by polyethylenglycol (PEG-6000) and to exogenous abscisic acid (ABA) applied in the nutrient solution which inhibits the stomata opening. Results from the measurements of leaf diffusion resistance, relative water content, transpiration and leaf elongation rates show dominant role of chemical signalization drought from root environment and of stomata in the regulation of water loss as well as sensitiveness of leaf elongation to lowered water availability. Maintenance of water content and turgor in the leaf tissues resulted from expression of morphological and physiological mechanisms of resistance and tolerance to drought different from that in mature plants which might be useful in the screening genotypes with different level of drought tolerance.
An Evaluation of Quantitative Traits Related to Drought Resistance in Inbred Lines of Maize in Stress and Non-Stress Conditions
Amir Ali Khalatbari,Mohammad Reza Bihamta,Amir Mahdi Khalatbari
Asian Journal of Plant Sciences , 2007,
Abstract: The objective of present study to evaluate the performance and resistance of a group of inbred lines selected under managed drought stress; to determine proper indices, those criteria with high correlation to yield and to apply practical analyses for superior genotypes based on the traits. In this research 30 inbred lines of corn were evaluated in field. Significant differences were observed among the Inbred lines for most traits in either stress or non-stress conditions. Most traits were negatively affected by drought stress, the highest reduction being observed in grain yield. The results of stepwise regression analysis showed that traits such as days to tassel initiation and days to pollination in non-stress condition could be used as desirable criteria for yield improvement. Under drought stress, traits such as number of ear per plant, number of rows per ear and number of seeds per row could be desirable criteria for yield improvement. Among the drought resistance indices, Mean Productivity (MP), Geometric Mean Productivity (GMP) and Stress Tolerance Index (STI) were the most suitable ones for drought resistance selection.
Croissance juvénile et comportement physiologique d'Andropogon gayanus Kunth var. bisquamulatus en conditions de stress hydrique
André Buldgen
Biotechnologie, Agronomie, Société et Environnement , 1997,
Abstract: Seedling growth and physiological behaviour of Andropogon gayanus Kunth cv. bisquamulatus in water stress conditions.Several studies carried on the physiology of Andropogon gayanus Kunth cv. bisquamulatus were conducted in Belgium in a wind tunnel simulating climatic conditions close to those prevailing during the rainy season in Sahelo-Sudanese region. The first experiments simulated water supply of 15, 20 and 25 mm at the outset of a caryopse sowing in a sandy soil. The observations were focused on daily evaporation losses, seedling emergencies, their growth and the mortality evolution. Results show that an initial soil water reserve of 25 mm, i.e. about 22.5 % in volume in the upper layer, is necessary to ensure the seedling survival during a period of 15 days after emergence. After 27 days, 95 % of the seedlings were still clive. With an initial soil water reserve of 13.5 or 18 % in volume (15 and 25 mm treatment respectively), mortalities occur already 4 to 6 days after sowing and increase vert' rapidly over a 10 day period. Whatever the initial water reserve mat' be, seedling losses occur systematically for a soil water reserve under or equal to 5 mm (4.5 % in volume). Two subsequent experiments were also conducted in order to analyse the photosynthetic parameters and the water status of 6 plants of Andropogon gayanus in the rainy and the dry seasons and during two drying cycles imposed in the rainy season. The first experiment shows that the hydric potentiel is -0.44 MPa during the rainy season and louver than -1 MPa during the dry season. The stomacal conductance is high (more than 1 cm . s-1) during both seasons, but the rate of photosynthesis decreases by half (from 19.8 to 10.9 graoles CO2 . m-2 . s-1) during the dry season. When the graminea endures a drought period in the rainy season, the physiological parameters evolve slowly until the soil water reserve reaches.
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