Variation of stomata dimensions and densities in tolerant and susceptible wheat cultivars under drought stress

Drought is one of the main limiting factors for plants production. Physiological traits such as number and size of stomata are important in selecting for drought resistance in breeding programs. In a greenhouse factorial experiment with two factors including the irrigation level and cultivar (comprise of 5 tolerant cultivars viz. Azar-2, Sardari, Son-64, 18-Yeknavakht-82, Sabalan, and 5 susceptible cultivars viz. Shahriar, Alvand, Tons, Kaspard, and Pishtaz), the role of stomata in the drought tolerance and the possibility Of using of these traits in breeding program were assessed. Water stress was imposed after emergence of the flag leaf, and sampling was performed when the flag leaves were fully expanded. Under the water deficit conditions the stomata length and the area of both upper and lower surfaces of the flag leaves decreased, but it didn't have effect on stomata density and width on both surfaces. The stomata density and width probably have been determined before drought imposition. The orthogonal comparisons of tolerant and susceptible cultivars showed that stomata length and density on the abaxial surface and stomata width and area on both of the surfaces for tolerant cultivars were highly significantly less than in the susceptible cultivars.