Effect of potassium chlorate on flowering, total nitrogen, total nonstructural carbohydrate, C/N Ratio, and contents of cytokinin-like and gibberellin-like substances in stem apex of 'do' longan

Abstract

The effect of potassium chlorate (KClO3) on flowering, total nitrogen (TN), total nonstructural carbohydrate (TNC), carbohydrate/nitrogen (C/N) ratio, and contents of cytokinin-like and gibberellin-like substances in stem apices of 'Do' longan were studied in CRD, with four treatments of KClO3at 0, 200, 500, and 800 g/tree by soil application. There were three replications with one tree/replication. The results revealed that all KClO3-treated trees were flowering before the untreated trees. TN of all KClO3-treated trees tended to be higher than untreated ones. TNC of all KClO3-treated trees tended to decrease before flowering (1st-3rd week) then increase after flowering, while the untreated trees tended to decrease gradually. During flowering period (2nd-5th week), C/N ratios of all KClO3treated and untreated trees were not significant different (P = 0.05). The contents of cytokinin-like and gibberellin-like substances were determined by soybean hypocotyl and rice secondary-leaf-sheath bioassays. The results revealed that the stem apices from all potassium-chlorate treatments had higher contents of cytokinin-like substance and lower gibberellin-like substance than the untreated trees. © ISHS.