Effects of Drought Stress on Some Anatomical Characteristics of Barley Leaves

In this research, effect of drought stress on leaf characteristics was investigated in the experimental field of Miandoab Azad University, Iran using four facultative barley cultivars. Two separate experiments were conducted in pot and field conditions. In both experiments a factorial arrangement was used and the treatments were completely randomized in four replications. In each experiment half of the experimental units were drought stressed and the other half were irrigated normally. For the pot experiment, plants were sampled at fourth leaf stage in order to obtain winter leaves. For the field experiment, when plants reached at late stem elongation stage, penultimate leaves were sampled and used for preparing microscopic slides. Xylem and phloem diameter and mesophyll, bundle sheath and epidermal cells area were measured in the transverse sections prepared from middle parts of the leaves. Significant differences were observed among genotypes under drought stress in terms of leaf characteristics. Results also showed that drought stress changes the diameter and the surface area of the cells. However, the changes were not the same in the winter and spring leaves. The changes in some cases such as diameter of xylem vessels were considerable. For example, in the cultivars Sahra and Jonob, the winter leaves had bigger xylem vessels under drought stress as compared to the normal condition while in the spring leaves the xylem diameter was smaller under the same condition.