Effect of priming and osmotic stress on the germination and activity of hydrolytic and glyoxylate cycle enzymes of hybrid maize (Zea mays L.) SC704 seed

This study was conducted as a factorial experiment to evaluate the effect of seed priming and osmotic stress on the activity ofhydrolytic and glyoxylate cycle enzymesin maize based on completely randomized design in  2012 at College of Agriculture, the University of Mohaghegh Ardabili. Treatments were four levels of osmotic stress originated from PEG 6000 (0, -3, -6 and -9 bar) and five levels of priming (Control, hydropriming, osmopriming, hormone priming and ascorbic acid) in three replications . The results showed that interaction of drought stress and priming was significant on all traits except of Germination Percentage and  isocitratelyase activity (only single effect of osmotic stress and priming was significant). The highest germination rate (17.556 seed day-1) observed in control drought. The highest activity of amylase, lipase and protease (4.43, 73.2 and 2071.3 unit mg-1 protein, respectively) observed in hormone priming and non-stress conditions. The lowest amylase activity (3.1 unit mg-1 protein) was related to osmo-priming and -9 bar drought while the lowest activity of lipase and protease (60.36 and 1949 unit mg-1 protein, respectively) observed in -9 bar drought in non-primed seeds. The highest activity of malate synthase (2.7 unit mg-1protein) observed in hormone priming and non-stress conditions, but the lowest activity (1.88 unit mg-1 protein) was related to -9 bar drought stress and non-primed seeds. Increase in the severity of stress decreased the germination rate and the activity of enzymes. Seed priming with gibberellic acid caused to resistance to drought conditions and prevention of decrease in the activity of hydrolytic and glyoxylate cycle enzymes in maize seeds