Investigation of physiological dormancy in buttum (pistacia khinjuk stocks) seeds stored in different periods and conditions

During period. s when adverse environmental factors reach challenging levels for life, developing adaptations that enable survival is a critical behavior for the survival of species. In plants, this behavior is achieved through dormancy, in which vital functions are reduced to a minimum. It is known that seed storage conditions and duration affect physiological dormancy. Wild Pistacia species, particularly Pistacia khinjuk Stocks (buttum), are used as pistachio rootstocks in our country, and low germination rates continue to be a problem in obtaining the desired number of rootstocks. In this study, newly harvested seeds, 1, 2, 3, and 4-year-old, were germinated at 4°C and 25°C to assess physiological dormancy. These germination data were supplemented with measurements of starch content and beta amylase activity in the endosperm, and abscisic acid (ABA), and gibberellic acid (GA3) in the embryo to understand physiological dormancy. In our study, the highest germination rate (81%) was obtained in newly harvested seeds germinated without any dormancy-breaking pretreatment. The highest starch amount (56 mg/g) in new ly harvest and the lowest (29.71 mg/g) were detected stored at 25 oC for 4 years in the endosperms of seeds. The highest beta amylase activity (26.86 EU/g) was observed in the endosperms of seeds stored at 25 oC for 4 years, and the lowest (10.95 EU/g) was observed in the endosperms of seeds stored at 25 oC for 3 years. The highest ABA/GA3 ratio (5.05 ng/g) was found in newly harvested seed in the embryos and the lowest (0.89 ng/g) was found in embryos that were stored for 3 years. It was observed that the storage temperature of the seeds did not have a noticeable effect on seed germination. Although there was a decrease in the ABA/GA3 ratio during storage, there was no noticeable increase in the germination rate. It was determined that with the decrease in ABA/GA3 value during storage, beta amylase activity increased and the starch amount decreased, but the germination rate did not increase. These findings suggest that alternative parameters should be investigated to determine physiological dormancy in P. khinjuk seeds.