Ali Asghar Ghaderi; Barat Ali Fakheri; Nafiseh Mahdi Nezhad
Abstract
In order to investigate the effects of foliar application of ascorbic acid on the growth indexes and physiological traitsof thyme under drought stress, an experiment was conducted in the split plots based on randomized complete block design with three replications at the Research Farm, Faculty of Agriculture ...
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In order to investigate the effects of foliar application of ascorbic acid on the growth indexes and physiological traitsof thyme under drought stress, an experiment was conducted in the split plots based on randomized complete block design with three replications at the Research Farm, Faculty of Agriculture University of Zabol, Iran. The main factor was drought stress and applied based on the irrigation at 75, 55 and 35% FC and the subplot was foliar application with three levels including distilled water (control), 10 mM and 20 mM ascorbic acid. Main effects of drought stress and foliar application of ascorbic acid were significant (P≤0.01) for all studied traits. The interaction of water stress and foliar application of ascorbic acid was significant only for proline. Applying severe stress compared with control was decreased the total chlorophyll, carotenoid, root and shoot dry weight (29.0, 39.9, 50.5 and 43.0%, respectively), while the leaf proline and the root length were increased (44.2 and 26.6%, respectively). The foliar application of ascorbic acid (20 mM) significantly increased the amounts of photosynthetic pigments, shoot length, root and shoot weight. Simple correlation coefficients of the traits showed a significant and positive relationship between shoot dry weight and other traits, in drought stress and 20 mM foliar application of ascorbic acid conditions. Factor analysis was identified four factors for normal and four factors for severe stress conditions that at overall were explained 98 and 95% of total variation, respectively. In general, it was concluded that photosynthetic pigments and root-related traits would be the important yield related criteria (shoot dry weight), that can be beneficial in the development of thyme with higher performance under stress conditions.