弱光下种植密度对冬小麦冠层温湿度及籽粒灌浆的影响

2016年在小麦拔节?成熟期用透光率为50%的白色尼龙网模拟遮阴环境，遮阴和自然光条件下分别设置450（M1）、525（M2）、600（M3）、675（M4）、750万株·hm?2（M5）5种种植密度，进行双因素裂区田间试验，观测对比冬小麦冠层空气温度、湿度以及小麦籽粒灌浆特性的变化过程。结果表明：与自然光相比，遮阴处理下冬小麦冠层温度明显降低、中午高温持续时间明显缩短，冠层湿度明显升高，中午冠层湿度低谷持续时间明显缩短，籽粒灌浆速率降低；遮阴显著降低了冬小麦的有效穗数、穗粒重及千粒重。遮阴条件下，可以通过适当降低种植密度，改善冠层温湿度，提高冬小麦籽粒灌浆速率，增加穗粒数和千粒重，从而获得高产。

Effects of Planting Population under Poor Light on the Canopy Temperature and Humidity and Grain-filling Properties of Winter Wheat

To study the effects of planting population under poor light on the canopy temperature, humidity and grain-filling properties of winter wheat, a white nylon mesh with a light transmittance of 50% was used to simulate the shading environment from jointing to maturity of winter wheat in 2016, a two factors split-plot field experiment including five plant population: 4.5 (M1), 5.25 (M2), 6.0 (M3), 6.75 (M4) and 7.5 million plants·ha?1 (M5) were conducted at circumstance of natural light and shading to observe and compare the variation of canopy temperature, humidity and grain filling characteristics of winter wheat. The results showed that, compared with natural light, the canopy temperature of winter wheat was significantly reduced under shading treatment, and the duration of high temperature at noon was significantly shortened. Under shading treatment, the canopy humidity increased significantly, the duration of humidity low valley at noon was shortened, and the grain filling rate, effective panicle number, grain weight per spike and 1000-grain weight were all decreased. Thus, under shading conditions, high yield could be obtained by appropriately reducing the planting population, improving the temperature and humidity of the canopy, increasing the grain filling rate, grain number per spike and 1000-grain weight.