Physiological and Morphological Characteristics of Drought-Stressed Chenopodium quinoa Willd, as Affected by Proline and Ascorbic Acid

In order to study the effects of proline and ascorbic acid on some morphological and physiological characteristics of quinoa in response to drought stress, an experiment was conducted as split plot based on randomized complete block design with three replications, during two consecutive years. The main factor was drought stress at three levels, namely irrigation after 30, 60, and 100 mm evaporation (control, mild, and severe stress, respectively) from class A pan. The second factor included foliar application of proline sulfate at three levels (40, 80, and 120 mg/l), foliar application of ascorbic acid at three levels (50, 90, and 130 mg/l), and control (no spraying). Drought stress reduced seed yield, relative water content, and growth indices. Ascorbic acid and proline treatments at each level of drought stress improved the traits under study. In general, by increasing the concentration of proline and ascorbic acid at all water deficit levels (specially in condition of no drought stress), no specific trend was observed on the studied traits while the treatments with 120 mg ascorbic acid and 130 mg proline provided the optimal growth conditions under mild and severe stress conditions.