The Function And Associated Mechanism Of Gibberellin On Bud Dormancy Release In Blueberry

Bud dormancy is a important physiological mechanism of going through the winter,and needs for a certain cold accumulation.Bud dormancy is a physiological protection mechanism for the overwintering of deciduous fruit trees.The release of dormancy need to go through a certain period of low temperature accumulation,lack of accumulation of low temperature,fruit trees can not release the natural dormancy,leading to not budding,not flowering or budding irregular,low fruit setting phenomenon.Blueberry has a high nutritional value and health effects,in recent years,China's blueberry introduction and cultivation has been rapid development.However,due to the impact of the natural environment and the lack of effective dormancy technology,in the warm winter region and the north to promote cultivation,the prevalence of low temperature accumulation and can not pass through the natural dormancy,seriously affected the economic benefits of blueberry cultivation,limiting the cultivation of blueberries the expansion of the area.Development can replace the low temperature of the efficient artificial dormancy technology is the blueberry cultivation in urgent need to solve problem.In the Japanese apricot,poplar research found that exogenous gibberellin?GA₄?can effectively break the bud dormancy.In this paper,the effects of exogenous GA₄ on the dormancy of blueberry buds and their related mechanisms were studied,which provided guidance for the artificial regulation and cultivation of blueberry dormancy.The main results are as follows:1.200 mg/L,500 mg/L and 1000 mg/L GA₄ could effectively released the dormancy of buds at different times during the dormancy of "bluecrop".The main cultivated varieties of greenhouse "M7",spraying of 500 mg/L GA₄ was carried out the day before warming.The flower buds were 8 days ahead of schedule,the inflorescence extension period was 13 days ahead,the inflorescence was 15 days ahead,the bud period 7 days in advance.2.The content of hydrogen peroxide and starch decreased,the content of endogenous GA₄ was significantly increased,and the content of methyl jasmonate?MeJA?was significantly decreased in the process of natural dormancy release.Exogenous GA₄ treatment could significantly decrease the starch content and increase the content of water,H2O2 and endogenous IAA,GA3,GA₄ and MeJA.3.In the process of natural dormancy of blueberry,the early accumulation of low temperature inhibited the expression of GA20 ox gene,induced the expression of GA2 ox gene and DELLA gene,the activity of endogenous GA decreased,the active growth of buds was stopped,bud dormancy was established,and CBF and DAM gene expression,maintain bud dormancy;long-term low temperature accumulation induced FT gene,KO gene up-regulated expression,inhibition of GA2 ox,DAM,dehydrogenase gene expression so that dormancy release.Exogenous GA₄ can inhibit the expression of DALLA gene,DAM gene and dehydrin gene,and promote the expression of GA20 ox gene and FT gene.