Zahra Khazaei - Ph.D student, Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran
Asghar Estaji - Assistant Professor, Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran

Salicylic acid (SA) is an important signal molecule modulating plant responses to stress. It is reported to induce multiple stress tolerance in plants including drought. An experiment was, therefore, conducted to ascertain the effect of salicylic acid on the growth, physiological and biochemical parameters of pepper seedlings under drought stress. This experiment is based on a factorial arrangement in a completely randomized design setting up of two factors: drought (irrigation within the field capacity, moderate stress and severe stress and SA in three levels (0 sprayed with distilled water, 0.5, and 1 mM) to three replications. The statistical results showed that SA effectively increased the vegetative parameters of pepper plant under drought stress and, despite drought stress, reduced the harmful effects of drought and increased crop production. Increasing the concentration of SA, Proline content, relative water content, chlorophyll index, fresh and dry weight of shoots and roots increased. In general, the results of this experiment suggest that salicylic acid provides pepper plant through its effect on vegetative, biochemical and physiological characteristics of the soil to better tolerate drought stress.

Field capacity, Proline, Relative water content