Biological Seasonal Study On The Growth And Development On Apical And Lateral Buds Of Idesia Polycarpa

In order to explore the biological seasonality of the growth and development of the apical and lateral buds of Idesia Polycarpa,this study carried out experiments on the dormancy process,physiological and biochemical responses of the buds,and the effects of the environment on the growth and development of the seedlings.Observations of the changes of physiological and hormonal indexes and the germination rate and time of winter buds in different periods of Idesia Polycarpa,the growth and the branches of the annual seedlings,to provide more theoretical basis for the cultivation,pruning and adaptability.The results are as follows:(1)Under the continuous illumination condition of 25℃,the dormant introduction period was from September to October,the germination rate of winter buds of Idesia Polycarpa was about 60% and the sprouting speed was slower and slower.When the germination rate dropped to 30% in November,it entered a deep dormancy period and also entered the dormant release period.After December 15 th,the germination rate of winter buds generally reached 100%,and the germination speed increased.However,the germination of winter buds was not accompanied by internode elongation until after February.(2)During the dormancy introduction period of winter buds,the content of soluble sugar was low,the activity of CAT and POD decreased continuously,and the protein content increased first and then decreased.The activity of CAT,POD and protein content reached the lowest level when entering the deep dormancy period.With the release of low temperature dormancy,soluble sugar content and protein content increased first and then decreased,the activity of SOD increased slightly,POD activity increased to a certain level and then stabilized,CAT activity increased slightly and then decreased to a low level,indicating that the content of winter buds in the period of dormant release from December to January can significantly improve the cold resistance,and adapt to the cold and dryness of winter.At the end of February and the beginning of March,the soluble sugar content,protein content,and CAT activity reached the lowest level,and the cold resistance decreased at the beginning of the endogenous growth period.After entering March,winter buds entered the germination stage,and various physiological and biochemical substances content and activity increased.(3)During the dormancy introduction period of buds,the IAA,ABA and GA3 began to decline after reaching the maximum on October 30,and t ZR continued to rise until November 15 th to reach its maximum value.At this time,the winter buds have entered a deep dormancy period,and the IAA in the buds has dropped to the lowest value,while the contents of ABA and GA3 remain at a high level,which also deepened the dormancy of the buds and improved the cold resistance of the winter buds.During the dormant release period,IAA and ABA levels decreased and remained at a low level,while GA3 and t ZR levels increased to a minimum at mid-December,then showed a sharp increase and remained at a high level,which accelerated the process of bud dormancy release.(4)Under the conditions of 25/15 °C and 30/20 °C,the effect of photoperiod on the high-growth process after the terminal buds sprouted was not significant.Under the constant temperature of 25 °C,the high growth process of the apical buds of Idesia Polycarpa showed a intermittent high growth process at 12 h and 16 h,but it showed a continuous high growth process at 20 h.The amount of high growth of shoot after apical bud germinated was maximum at 12 h,and the difference was significant with 16 h.(5)The growth of lateral buds after germinated could be induced to form Sylleptic branches at the 25/15 ℃temperature varied from 16 h to 20 h,the day length longer the number of branches fewer,but the length of the branches larger;At 30/20 ℃,the day length must be as long as 20 h the lateral buds could be induced germination and branching;Under the constant temperature of 25 °C,the seedlings of Idesia Polycarpa treated with three kinds of photoperiods all sprouted into side branches.