The impact of seedling drought stress and recovery on chlorophyll fluorescence parameters and physiological characteristics of wheat

In order to examine the impact of drought stress and re-irrigation on chlorophyll fluorescence parameters and physiological traits of three wheat cultivars at five levels of irrigation, an experiment was performed in a factorial arrangement with complete randomized design in three replications. The traits comprised of chlorophyll fluorescence parameters (F0, Fm, Fv and Fv/Fm) and physiological characteristics included relative water content, leaf temperature and relative content of chlorophyll were measured .The results showed that the relative water content and chlorophyll relative content were decreased but leaf temperature was increased under drought stress. Similarly, the chlorophyll fluorescence parameters Fm, Fv and Fv/Fm increased but F0 decreased under drought stress and these changes in tolerant cultivars were less severe than susceptible cultivar. The re-irrigation treatment caused these traits in the stressed plants to be similar to normal conditions, where it was lower for susceptible cultivars than the resistant cultivar. The results of correlation among all traits showed significant positive and negative relations, that the highest indices was recorded between Fm and Fv parameters (r=0.991**) and between Fv/Fm. and F0 (r=0.926**).