Impact of osmotic stress on physiological and biochemical characteristics in drought-susceptible and drought-resistant wheat genotypes

Abstract

In this study, the seedlings of two wheat cultivars were used: drought-resistant Chinese Spring (CS) and drought-susceptible (SQ1). Seedlings were subjected to osmotic stress in order to assess the differences in response to drought stress between resistant and susceptible genotype. The aim of the experiment was to evaluate the changes in physiological and biochemical characteristics and to establish the optimum osmotic stress level in which differences in drought resistance between the genotypes could be revealed. Plants were subjected to osmotic stress by supplementing the root medium with three concentrations of PEG 6000. Seedlings were grown for 21 days in control conditions and then the plants were subjected to osmotic stress for 7 days by supplementing the root medium with three concentrations of PEG 6000 (D1, D2, D3) applied in two steps: during the first 3 days of treatment -0.50, -0.75 and -1.00 and next -0.75, -1.25 and -1.5 MPa, respectively. Measurements of gas exchange parameters, chlorophyll content, height of seedlings, length of root, leaf and root water content, leaf osmotic potential, lipid peroxidation, and contents of soluble carbohydrates and proline were taken. The results highlighted statistically significant differences in most traits for treatment D2 and emphasized that these conditions were optimum for expressing differences in the responses to osmotic stress between SQ1 and CS wheat genotypes. The level of osmotic stress defined in this study as most suitable for differentiating drought resistance of wheat genotypes will be used in further research for genetic characterization of this trait in wheat through QTL analysis of mapping population of doubled haploid lines derived from CS and SQ1.

Alleviation of Osmotic Stress Effects by Exogenous Application of Salicylic or Abscisic Acid on Wheat Seedlings

“…This data is in agreement with the results obtained in our previous experiment [33]. Supplementing SA or ABA to the medium (PEG + SA or PEG + ABA) caused a decrease of these seedling parameters for both cultivars.…”

“…It was shown that the optimal level of osmotic stress—defined as most suitable for differentiating drought resistance of SQ1 and CS wheat cultivars based on the differences in the response to osmotic stress caused by PEG—was −0.75 MPa [33]. Osmotic stress was found to affect water status, seedlings morphology, gas exchange parameters, chlorophyll content, osmotic potential, lipid peroxidation, water soluble sugars and proline contents in drought resistant and drought susceptible wheat cultivars.…”

QTL mapping for germination of seeds obtained from previous wheat generation under drought

“…The parental forms differ in tolerance to drought and present diverse physiological responses and yields. These characteristics were previously confirmed in earlier studies [23,25,26].…”

Alleviation of drought-induced oxidative stress in maize (Zea mays L.) plants by dual application of 24-epibrassinolide and spermine

“…Plants can avoid the damage brought about by drought through several mechanisms such as compatible solutes accumulation (Marci nska et al, 2013). Organic solutes can accumulate to high level without disturbing intracellular biochemistry, protecting sub-cellular structures, mitigating oxidative damage caused by free radicals and maintaining the enzyme activities under different environmental stress conditions (Hanson et al, 1977;Hanson and Nelsen, 1978;Ashraf and Foolad, 2007;Marci nska et al, 2013;Talaat andShawky, 2013, 2014a).…”

“…Organic solutes can accumulate to high level without disturbing intracellular biochemistry, protecting sub-cellular structures, mitigating oxidative damage caused by free radicals and maintaining the enzyme activities under different environmental stress conditions (Hanson et al, 1977;Hanson and Nelsen, 1978;Ashraf and Foolad, 2007;Marci nska et al, 2013;Talaat andShawky, 2013, 2014a). Furthermore, during drought stress excessive generation of reactive oxygen species (ROS) such as superoxide radical (O 2 ROS and maintain redox homeostasis, plants have developed a well-integrated antioxidant defense system, which is made up of antioxidant molecules and antioxidant enzymes such as superoxide dismutase, catalase, and enzymes involved in the ascorbateglutathione cycle (Mittler, 2002).…”