Different physiological and biochemical responses in maize hybrids subjected to drought stress at vegetative and reproductive stages

摘要

The growth and development of all plants are seriously limited by a variety ofenvironmental stresses. In this study, responses in crop yield, physiological and biochemicaltraits were investigated in maize (Zea mays L.) hybrids such as SC704, SC700 (FAO 700), SC647(FAO 600), SC500 (FAO 500), SC370 (FAO 300) and SC260 (FAO 200) subjected to drought stressinduced by stopping irrigation at vegetative stage (4-5 leaves) and reproductive stage (anthesis).The results showed that drought stress had a significant effect on these characteristics. The yieldand its components decreased considerably under water stress: the main factors that causedreduction of yield were the decrease in the number of grain per ear and 1000-grain weight.Reduction of yield in short maturity hybrids was higher than in other ones. Activity of superoxidedismutase (SOD) as well as permeability of plasma membrane increased significantly, but ascorbateperoxidase (APX) activity decreased under water stress. Maximum quantum efficiency ofPSII (Fv/Fm) and performance index (PI) revealed a significant reduction in leaves in comparisonwith control plants. The content of soluble proteins in leaves reduced with increasing droughtstress. These results suggested that water stress lead to the production of reactive oxygen species(ROS), which caused an increased membrane permeability and oxidative stress in the maizeplants. Furthermore, maize hybrids with higher levels of antioxidant enzyme activities showedhigher resistance to drought stress and produced higher yield under stress. So that SC704 andSC700 were the most tolerant, however, SC647 and SC500 were drought semi-tolerant to waterstress, and SC370 and SC260 were the most sensitive.