花铃期渍水对棉铃对位叶蔗糖代谢及铃重的影响

试验以新棉33B为材料，于2007年和2009年在江苏南京(32º02′N，118º50′E)江苏省农业科学院防雨棚的水泥池中进行。以正常灌水(土壤相对含水量为75%±5%)为对照，于棉花中部(6~8)果枝开花时进行渍水7 d和14 d (保持地面2~3 cm的水层)处理。研究花铃期渍水对棉铃对位叶蔗糖代谢及铃重形成的影响。结果表明，花铃期渍水条件下棉铃对位叶可溶性糖、蔗糖、淀粉含量增加，蔗糖/淀粉比值下降，且随渍水持续期的延长变化幅度增大，表明花铃期渍水致使叶片蔗糖外运受阻且随渍水时间的延长外运受阻加重；棉铃对位叶蔗糖磷酸合酶、蔗糖合酶和酸性转化酶活性增强，且随渍水持续期的延长和果枝部位的上升而增大；棉铃对位叶可溶性糖、蔗糖和淀粉含量与蔗糖磷酸合酶、蔗糖合酶及酸性转化酶活性显著正相关(P<0.05)，表明渍水条件下蔗糖代谢被激活但并未促进叶片蔗糖的外运，铃重随果枝部位上升和渍水持续期的延长下降幅度增大。这是渍水条件下铃重下降的重要原因。

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

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 (P<0.05), 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.