覆膜和水分亏缺对制种玉米灌浆期气体交换参数及产量的影响

Effects of water deficit and mulching on leaf gas exchange parameters and yield in seed-maize grain filling stage

为了揭示西北干旱地区水分亏缺条件下,覆膜对灌浆期玉米叶片光合生理特征及产量的影响规律,于2017年在中国农业大学石羊河流域农业与生态节水试验站进行了大田试验,设置2种覆膜方式(覆膜滴灌M1和不覆膜滴灌M0)和5种灌水处理(W1—W5),共10个处理.试验结果表明:在处理W1和W2下,气孔限制是光合速率下降的主要原因;在处理W3下,不覆膜方式以非气孔限制为主,而覆膜方式气孔限制和非气孔限制可能同时存在;在处理W4和W5下,非气孔限制成为光合速率下降的主要原因.覆膜具有明显的增产效果,与不覆膜方式差异具有统计学意义,轻度水分胁迫可以提高玉米叶片的净光合速率,有利于玉米增产.综上所述,在西北干旱地区,水分亏缺条件下,覆膜能够提高玉米的产量和收获指数;轻度水分亏缺时,植物通过气孔限制进行水分调控,而重度水分亏缺时,非气孔限制成为光合速率下降的主要因素.

In order to investigate the response of maize photosynthetic characteristics and yield to water deficit and plastic-mulching in grain filling stage in arid areas of northwest China, a field experiment was conducted in Shiyanghe Basin Agriculture and Ecological Water-saving Experimental Station of China Agricultural University in 2017. Two plastic-mulching conditions （mulching M1 and non-mul- ching M0） and five irrigation levels （W1 to W5） for 10 treatments in total were designed for the experi- ment . The results show that the stomatal restriction is the main reason for the decrease of photosynthe- tic rate in W1 and W2 treatments. In W3 treatments, the non-mulching treatments are dominated by non-stomatal restriction, while both stomatal and non-stomatal restrictions might exist simultaneously in the mulching treatments. In W4 and W5 treatments, the non-stomatal restriction is the main reason for the decrease of photosynthetic rate. The yield of maize in mulching treatments is significantly higher than that in non-mulching treatments. A mild water stress can improve the net photosynthetic rate and the yield of maize. In conclusion, under water deficit condition, mulching can increase the yield and harvest index （ HI ） of maize in arid areas of northwest China. Stomatal restriction is the main regulating factor in mild water deficit. In non-stomatal restriction, however, non-stomatal restriction becomes the major limiting factor in serious water deficit.