فرزاد رسولی

Drought stress is one of the most critical environmental stresses. Water deficit is a multidimen- sional stress and affects physiological, morphological, biochemical and molecular traits in plants. Many plants could be improving their tolerance mechanisms over drought stress, although the mechanisms vary and depend on a plant species. Almond species are mainly known as drought-tolerant trees and shrubs and are adapted to arid and semi-arid environments. This study aimed to evaluate morphological, nutritional, and physiological responses of 4 almond cultivars (Talkh, Nonpareil, Azar, and Sanghi) under drought stress. During 90 days of the growing season, drought treatment was applied at 4 levels of field capacity (control, 75%, 50% and 25%). To assess the response of the almond varieties to drought stress, the plant height, root length, internode length, fresh (FW) and dry weight (DW) of shoot and root, leaf area, proline, malondialdehyde (MDA) and elements content such as N, P, K, Ca, Mg and Fe were evaluated. The present study results showed that drought stress decreased mor- phological traits and increased proline and MDA accumulation in all the evaluated almond cultivars. Also, increasing drought stress was associated with reducing the content of the ele- ment in all the cultivars. According to our findings, it can be concluded that Sanghi and Azar cultivars are more tolerant to drought stress than Talkh and Nonpareil.