The Regulatory Technique And Mechenisms In Lateral Branching Of Standard Cut Chrysanthemum

The production of cut flower Chrysanthemum morifolium needs artificial erasion of lateral branches or buds,so it is necessary to breed the Chrysanthemum morifolium cultivars with less lateral branches for saving a large amount of manpower and resources.However,it is confronted with the issues of less buds and cutting slips from maternal parents by breeding of cultivars with less lateral branches,especially in high temperature,making it very difficult to propagate massively of the seedlings.Thus,there are practical and theoretical significances for studying the regulation technique and mechenism of cut flower Chrysanthemum morifolium with less lateral branches.In order to investigate the methods of promoting growth of lateral branches of Chrysanthemum morifolium cultivars with less lateral branches,and to lay the foundation of promoting the cultivation of those cultivars,this research studied the influence on germination and growth of lateral buds of'Sei No Issei' in field and in vitro with the treatments of extraneous hormones and high temperatures.Besides,the mechanism of regulating growth of lateral buds and endogenous hormones of Chryanthemum morifolium cultivars with less lateral branches by extraneous hormones and high temperatures were discussed based on the results which are stated as the following.(1)The cutting slips with high quality of 'Sei No Issei' were obtained after spraying 10 mg-L-1 KT,and the most amounts of cutting slips which are 2.26 times more than CK were obtained in threatment with 20 mg·L-1 6-BA.There are no significant affection on various parameters in most treatments with different hormones.However,the effect on rooting of cutting slips with 100 mg· L-1 GA3 are the best,in which the rooting time was one day in advance and the length and the weight of roots increased significantly.The treatment of 20 mg·L-1 6-BA could not promote the quanlity of cutting slips,but increased the harvest.Spraying one time in the first day,and one times in first day,third day and sixth day respectively created better harvests which were the three and four times of CK.Compared with CK,after spraying 6-BA,the hormones in lateral buds changed significantely which affected the growth of lateral branches.IAA and GA3 might be positively correlated with the length of lateral branches.(2)Compared with the relative low temperatures(20 ?/18 ?),the treatment with higher tempratures(30 ?/28 ?)could promote the numbers and length of lateral branches,but the increasement of numbers by temperatures only occurred within 15 d.After pinching,the germination and growth of lateral buds at different positions of plants were significantely different.The order of average number and length of lateral branches followed by upside>middle part>bottom.There were also difference of hormones concentrations in lateral buds at different positions.The contents of IAA at the upside and the bottom were higher than that at the middle part.The contents of ZT and GA3 decreased along with the downward positions,whereas the contents of ABA increased.To some extent,high temperatures regulated the endogenous hormones,thereby controlling the growth and development of lateral branches.IAA and GA3 might be positively correlated with the length of lateral branches.(3)The budding speed of the middle stem was higher than the upper and the lower part,and that the long branches increased from the upper part to the lower part.The content of IAA and ABA was much higher than the middle and the lower ones.The ZT/IAA value of the middle part was the highest,while the middle part was lower.The middle and the lower part are much higher the values of ZT/ABA,GA/ABA,IAA/ABA and ZT/IAA than those of the upper part.The increased exogenous NAA could lead to a decrease in the lateral budding rate and long branches rate and the endogenous ZT level,while the endogenous IAA level raised with no effects on the content of endogenous GA and ABA.As a consequence,the ZT/ABA and ZT/IAA decreased significantly.The lateral buddings rate and the endogenous ZT level increased obviously with the treatment of 0.5 mg·L-1 and 1.0 mg-L-1 6-BA,but the long branches rate and the levels of endogenous GA and IAA reduced significantly,which led to an increase in the ZT/ABA and ZT/IAA ratios.In addition,high temperature(30 ?)suppressed lateral buddings,long branches,and the levels of endogenous ZT and GA significantly,while promoted the endogenous ABA level,thus the ZT/IAA,IAA/ABA,ZT/IAA and(GA+IAA+ZT)/ABA ratios decreased significantly.Whereas,the axillary buds could sport and grow normally at 25 ?.It is suggested that middle or lower stems could be selected for a large-scaled propagation for the 'Sei No Issei',and the 0.5 mg·L-1 6-BA in medium and 25 ? condition would boost axillary buddings and long branches further.