The effect of climate on water content, dormancy and dehydrins expression pattern in pistachio seeds

The environmental conditions which the parent plant has undergone during seed development can affect many properties of the seeds such as degree of dormancy, weight and the amount of their compounds. In this study, mature pistachio seeds of Ahmadaghaei cultivar, collected from the two cities of Rafsanjan and Shahrbabak located in Kerman Province (Iran), were compared. It was found that the seeds collected from Shahrbabak being a cooler and wetter region had a longer dormancy, although the water content of the two seed series were similar. Dehydrin proteins generally play a role in protecting plant cells against dehydration stress. Dehydrin contents of the cotyledons and embryonic axes of the two seed series were compared by western blot method using an antibody against the conserved K segment in dehydrin proteins. It was found that the cotyledons had five dehydrin versions with molecular weights of 23, 25, 32, 39 and 48 kDa, the expression of which not being influenced by environmental factors. It was found that the embryonic axes had seven other versions of dehydrin with weights of 17, 19, 20, 28, 67, 77 and 98 kDa in addition to those five versions. This shows higher protection of embryonic axes compared with the cotyledons. The 25 and 28 kDa versions had higher expression levels in embryonic axes of Shahrbabak seeds, while the 39 kDa version had a higher expression level in embryonic axes of Rafsanjan seeds.