Growth and Survival of Willow Seedling (Salix alba L.) Under Water Deficit Stress

Willows due to the rapid growth rate, low nutrient requirements, resistance to many pollutants, and environmental stresses are ideal candidates for developing the landscapes and reducing the environmental degradation. The purpose of this study was to determine the response of Salix alba seedling to water deficit conditions. This experiment was set up as complete randomized design with five irrigation periods (2, 4, 6, 8 and 10 days) in three replicates (each replicate containes five pots) for four months. Results indicated a high survival rate for Salix seedlings, whereas under extremely drought stress (10-day irrigation) it was always greater than 73%. Height and collar diameter growth, above-ground and under-ground biomass, number of leaves and root volume decreased with increasing the irrigation period but no changes occurred in leaf area, specific leaf area, root length and root:shoot ratio. Regarding to the economy of water resources, 6- and 8-day irrigation periods, due to high survival (100%) and favorable growth of seedlings, can be considered for raising salix alba seedlings in this region and/or in climatic regions similar to the research site.