根修剪对冬小麦根系效率、水分利用及产量的影响

通过盆栽试验研究了根修剪对冬小麦根系效率、水分利用及产量形成的影响.结果表明,在不同水分条件下,根修剪均减少了小麦的根量及根呼吸速率,但对根冠比没有显著影响.在湿润和中度干旱条件下,根修剪提高了小麦花期的光合速率和根系效率;在严重干旱胁迫条件下,根修剪小麦的光合速率显著下降,但根系效率与对照相比没有显著差异.在湿润条件下,小剪根处理对籽粒产量并没有显著的影响,而大剪根处理小麦的籽粒产量显著下降;在中度干旱胁迫条件下,小剪根处理小麦的产量(25.18 g pot-1)显著高于对照(22.31 g par-1),但大剪根处理小麦的产量(18.34 g pot-1)显著下降;在严重干旱条件下,两个剪根处理小麦的产量均显著下降.在湿润和中度干旱胁迫条件下,小剪根处理籽粒产量水平的水分利用效率(分别为1.57 g kg-1和1.85 g kg-1)显著大于相应的对照处理(分别为1.46 g kg-1和1.55 g kg-1),但大剪根处理水分利用效率和对照相比没有显著差异;在严重干旱条件下,各剪根处理的水分利用效率和对照相比没有显著差异.可见,在湿润和中度干旱条件下进行的适当根修剪根对作物生产是有利的.图1表3参15

Effect of Root Pruning on Root Efficiency, Water Use and Yield of Winter Wheat

A pot experiment was conducted to study the effects of root pruning on root efficiency, yield and water use efficiency (WUE) of winter wheat. The results showed that root pruning reduced root weight and root respiration rate, but not affected root/shoot ratio of winter wheat. Under well-watered and moderate drought stresses, the wheat with root pruned had significantly higher photosynthetic rate and root efficiency compared with the control. Under severe drought stress, the pruned wheat had significantly lower photosynthetic rates, but would not significantly affect root efficiency. Under well-watered condition, the lightly pruned roots had no significant effect on grain yield, but the heavily pruned roots would significantly reduce wheat yield. Under moderate drought stress condition, the wheat with the lightly pruned roots had significantly higher yield (25.18 g pot~(-1)), but the heavily pruned wheat had significantly lower yield (18.34 g pot~(-1)) compared with the control (22.31 g pot~(-1)). Under severe drought stress, both root pruning treatments significantly reduced the grain yield of wheat. Under well-watered and moderate drought stresses, lightly pruned wheat had significantly higher WUE (1.57 g kg~(-1) and 1.85 g kg~(-1), respectively) compared with the control (1.46 g kg~(-1) and 1.55 g kg~(-1), respectively). However, the heavily pruned roots had no significant effect on WUE of wheat. Under severe drought stress, both root pruning treatments had no significant effect on WUE of wheat. It is obvious that suitable root pruning would be beneficial to improving crop production under well-watered and moderate drought stresses. Fig 1, Tab 3, Ref 15