Effect of Different Concentrations of Brassinosteroid on Physiomorphological Characteristics of Five Pistachio Genotypes (Pistacia Vera. L)

Brassinosteroid as one of steroid hormones has an integral role in controlling plants physiological process especially in response to biological and non-biological stress. This research has been done in Damghan Islamic Azad University Greenhouse. The influence of four concentrations of plant growth regulator -24, homobrassinolide with concentration of 0,10 -10 , 10 -8 ,10 -6 molar on null seedlings of pistachio genotype sort based on factorials experiments on the basis of completely randomized block design with four replications was performed. After foliar spraying in six leaves stage of pistachio seedlings and after passing six weeks, somephysio-morphplogical characteristics such as the size of photosynthesis pigments, leaf area index, seedlings height, biomass (the wet and dry weight of root and shoot), and lipoxygenase enzymes were scrutinized.The result indicated that foliar spraying experiment with brassinosteroid hormones had significant effect on some evaluated traits (P). Maximum leaf area index with concentration of 10 -10