Water Stress Effect on Anatomical and Physiological Characteristics of Two Wheat (Triticum aestivum L.) Cultivars

The aim of this study was to determine the effects of water stress on the anatomy of xylem and phloem vessels, mesophyll and epidermal cells, relative water content and ion transfer rate of two wheat cultivars including Azar2 as drought tolerant and Shole as drought susceptible cultivars at four leaf stages. Seeds were sown in pots under normal (soil water content at 100% of FC) and the water stress (60% of FC) conditions in a factorial experiment based on CRBD design at the Experimental Farm of Kerman University in 2011. Four samples were taken from different positions of the fully expanded 4th leaf. Results showed that in both cultivars water stress decreased the xylem and phloem vessel diameter and the area of the mesophyll and upper epidermal cells at all positions. However, no significant effect of water stress by cultivar interaction was found on lower surface epidermal cell size and RWC. Water stress effect on the amount of ion leakage up to 30 min after soaking the leaf samples in distilled water was highly significant while it was not significant at 60 min after soaking. The effect of water stress on ion leakage was higher in Shole compared to Azar 2. Anatomical changes of the wheat leaf under water stress condition can be considered as adaptation responses. The effects of such anatomical changes on the final yield need to be investigated in future studies.