棉花苗蕾期喷施生长调节剂促早熟效应研究

Applying Plant Growth Regulators at Early Stages Affects Maturation of Cotton

【目的】在我国大部分棉区,早发早熟是棉花优质高产的前提。本研究探究了苗期和蕾期应用植物生长调节剂对花芽提早分化并提高后期吐絮率的效果,旨在为促进棉花早熟提供技术支持。【方法】在温室盆栽和田间条件下,于子叶期至蕾期叶面喷施不同浓度的植物生长调节剂,比较第一果枝节位、现蕾数和后期吐絮率的差异。【结果】在温室盆栽条件下,子叶期喷施140μmol·L^-1赤霉素(GA3)或子叶期、2叶期、4叶期连续3次喷施2.23μmol·L^-1复硝酚钠(CSN)均可使果枝始节位降低约0.9。在田间条件下,子叶期喷施288、576μmol·L^-1赤霉素4+7(GA4+7)使第一果枝节位显著降低约0.4;3叶期喷施6-苄氨基嘌呤(6-BA)44.4μmol·L^-1,第一果枝节位显著降低0.2;但第一果枝节位与9月下旬的吐絮率之间无显著相关关系,即第一果枝节位降低并不意味着后期吐絮率提高。蕾期应用0.10μmol·L^-1油菜素内酯(BR)可提高9月下旬的吐絮率,主要与其增加中下部果枝的成铃比例有关。【结论】优化成铃分布较提早花芽分化、降低第一果枝节位对棉花促早熟更重要。

[Objective]Early initiation and early maturity are the foundation of high yield and good quality of cotton.The purpose of this study is to determine the effects of plant growth regulators applied at the seedling and squaring stage on the early initiation of flower bud and the rate of the opened cotton boll(ROCB)during later development period,and to provide practical measures for hastening the maturity of cotton.[Method]Several plant growth regulators were applied from cotyledonary to squaring stage under greenhouse and field conditions,water was used as the control.The first fruiting branch node(indicating the initiation of flower bud),the number of bud prior to blooming and the ROCB at mid-term of boll maturation period(23 September,2017)were compared among treatments.[Result]Under greenhouse conditions,gibberellic acid(GA3)applied at the cotyledonary stage with 140μmol·L^-1 as well as the three consecutive applications of sodium nitrophenolate(CSN,2.23μmol·L^-1)at the cotyledonary,two-leaf and four-leaf stage made the first fruiting branch node move down by about 0.9 nodes.In field experiments,the application of gibberellin4+7(GA4+7,288 and 576μmol·L^-1)at the cotyledonary stage significantly decreased the first fruiting branch node by about 0.4 nodes.Also,the application of 6-benzylaminopurine(6-BA,44.4μmol·L^-1)at the three-leaf stage significantly decreased the first fruiting branch node by 0.2 nodes.However,there was no significant correlation between the first fruiting branch node and the ROCB in late September.Moreover,the application of Brassinolide(BR,0.10μmol·L^-1)at the bud stage increased the ROCB in late September,which was mainly associated with the increased boll set in the lower and middle fruiting branches.[Conclusion]The reasonable distribution of bolls(concentrated in the lower and middle fruiting branches as well as inner fruiting sites)is more important for the earliness of cotton than lowering the first fruiting branch node.