Effects of Waterlogging on Sucrose Metabolism of the Subtending Leaf of Cotton Boll and Boll Weight during Flowering and Boll-forming Stage

Abstract

Two year experiments were conducted at experimental station of Jiangsu Academy of Agricultural Sciences of Nanjing City with waterlogging treatments for seven days and fourteen days in pools with rainproof shelter at anthesis of the 6th or 8th fruiting branches of cotton NuCOTN 33B, taking well water conditions as control. The results showed that contents of soluble sugar, sucrose and starch of subtending leaves of bolls increased and the ratio of sucrose content to starch content decreased under waterlogging as compared with control and the increase ranges rised with lasting waterlogging duration, indicating that the sucrose exportation of subtending leaves was inhibited and became worse with lasting waterlogging duration. The activities of sucrose phosphate synthase(SPS), sucrose synthase(SS), and acid invertase(AI) increased and got higher with the rise in fruit branch position and waterlogging duration. The contents of soluble sugar, sucrose and starch were positively and significantly correlated with activities of SPS, SS, and AI(P0.05), indicating that the increased activities of SPS, SS, and AI do not facilitate sucrose transiting out. As a result, the boll weight declined under waterlogging with the rise in fruit branch position and waterlogging duration. Therefore, the increased enzyme activity in sucrose metabolism and the impaired sucrose efflux are the main causes of boll weight decrease under waterlogging.