Plant water relations and seedling growth of three pistachio cultivars as influenced by irrigation frequency and applied potassium.

摘要

Despite the economic importance of pistachio (Pistacia vera) crop, very little information is available on its water needs and nutrient requirements. Therefore, the effects of three irrigation frequency (1, 3, and 7 days) and five potassium (K) levels (0, 75, 150, 225, and 300 mg kg-1) on the plant water relations and growth of three pistachio cultivars (Badami, Ghazvini and Sarakhs) were studied in a glasshouse experiment. After 30 weeks, the dry weights of leaves, stems and roots were measured, and the total leaf area was determined together with the number of leaves per pot and stem height. The effect of water frequency and potassium application on the leaf water potential, osmotic potential, and turgor potential was studied. Increased irrigation intervals decreased all of the above growth parameters. Shoot dry weights were reduced by 50% and 68% for Badami, 42% and 66% for Ghazvini, and 26% and 46% for Sarakhs at the 3- and 7-day irrigation intervals, respectively. Leaf water potential and turgor potential unexpectedly were increased by increase in water frequency. However, water frequency decreased leaf osmotic potential. The potassium application had no significant effect on the leaf water potential, osmotic potential and turgor potential. It seems that NH4OAc-extractable K (70 mg kg-1) was probably sufficient for optimum seedling growth of pistachio. Furthermore, Sarakhs proved to be the most tolerant cultivar to drought stress..