Evaluation of enzymatic changes during flower bud dormancy in several apricot cultivars based on accmulation chilling requirement (Prunus armeniaca)

Apricot tree (Prunus armeniaca L) is one of the most important horticultural crops in Iran, particularly in Azerbaijan region. To evaluate the enzymatic changes and proline content during the dormancy in four apricot cultivars including, “ Tabarze,” “Shamloo,” “ Shekarpare “ and Asgarabad, the present study was conducted during 2013-2014 in the Khalatpoushan research station ( Department of Horticulture , Faculty of Agriculture, the University of Tabriz). In this study, changes in the activity of some enzymes including, catalase, peroxidase, superoxide dismutase and proline were measured during dormancy. The results showed that there was a significant difference in all three enzymes activities. The flower buds exhibited high level of enzyme activities at the initial phase of dormancy and the amount of mentioned enzymes have been decreased after the accumulation of chilling requirement. The interaction between cultivar and chilling accumulation in all three enzymes showed that, “Tabarze” had the least enzymes activity at 141 chill unit and after the accumulation of 621 chill unit “Asgarabaad” showed the highest amount of enzymes activity. Investigation of proline changes in the studied cultivars during dormancy showed that, there was a significant difference between different dates of sampling , so that, “Tabarze” and “Asgaraabad” in November had the least proline and Shamloo in January showed the highest proline content. Therefore, the biochemical changes during chilling requirement play an important role in breaking of endo-dormancy and they can be used as biochemistry marker in detection of low, intermediate and high chilling requirement cultivars in fruit trees.... .