Abstract：This study was designed to elucidate the relationship between endogenous hormone contents and head-splitting character of Brassica oleraca L.var.capitata L.Enzyme-linked immunosorbent assays(ELISA)was used to determine the contents of indoleacetic acid(IAA),gibberellin(GA3),cytokinin(ZR)and abscisic acid(ABA)and to analyze their ratio changes,so as to probe into the relation between head-splitting and endogenous hormone.These endogenous hormones were taken from head leaves of 4 Brassica oleraca L.var.capitata L.cultivars which differ in splitting susceptibility during vegetative period.The results showed that during the whole vegetative period,the contents of IAA and GA3 in splitting-resistant cultivars were higher than those of splitting-susceptible cultivars.ZR content had less effect on head-splitting of Brassica oleraca L.var.capitata L.ABA content was the highest among the 4 endogenous hormones,and there were great dynamic differences between splitting-resistant and splitting-susceptible cultivars.The high ratio of(IAA+GA3+ZR)to ABA at the late stage could keep the Brassica oleraca L.var.capitata L.head in a strong growing vigor,thus reduce the headsplitting probability.
