Abstract: The purpose of this study was to investigate the relationship between the changing of chemical detopping cottons' endogenous hormones and spatial distribution of boll branch. The present objective of this study was to measure four hormones,diurnal variation by Elisa inverse fourth leaf of cotton after detopping,North Xinjiang Early maturing cotton No.45 was the cotten variety,set the chemical(C)and two contrast group:no(CK)and artificial detopping(M). The results indicated that the IAA contention after chemical detopping(C)has decreased trend more obviously and rapidly than the no detopping(CK)and artificial detopping(M),and remained at a low level after 168 h;the GA₃ contention had no much difference about chemical topping(C)and no topping(CK),which provides a theoretical basis for the cotton "Secondary growth";the CTK contention of cotton after chemical(C)had slower rising speed than no topping(CK)and artificial topping(M),but it had maximum peak value,and remained at a higher level after 168 h;the ABA contention after chemical(CK)has maintained a high level until the end of the experiment. The experimental indexes'peak and bottom peak appeared in processing that proved chemical detopping could change the cotton endogenous hormone significantly inverse fourth leaf of cotton. Meanwhile chemical detopping could effectively control the cotton boll branch length,which were distributed mainly in the middle and lower branch,at the top of ball has obvious advantages compared to artificial detopping. The research provides certain theoretical basis for chemical detopped cottons'spatial distribution of boll and branch is regulated by the endogenous hormones.

Key words: Cotton, Chemical detopping, Inverse fourth leaf, Endogenous hormone, Spatial distribution of boll

CLC Number: 

• S562.01