光照和温度对旱地小麦叶面积指数的影响

为研究旱地小麦叶片生长规律，了解气候变化对小麦叶面积指数的效应，设计回归正交组合试验，并运用APSIM模型模拟光照和温度变化对小麦叶面积指数的影响。结果表明：APSIM模型对小麦叶面积指数的模拟有较高精度。小麦叶面积指数与光照和温度分别呈开口向下和向上二次抛物型变化。在本试验范围内，叶面积指数与光照呈二次抛物线下降型变化，但当光照未越过临界点时，光照成正效应，表明在最适宜条件下光照的合理增加可促进小麦生长；当日均气温高于7.73 ℃，温度成正效应，说明温度合理的升高，有助于小麦叶面积指数在一定生长阶段平稳在较大值；光照和温度同时升高时，光照下降效应显著于温度正效应。

Effects of Light and Temperature on Leaf Area Index of Wheat in Dryland

In order to explore the effect of light and temperature on wheat leaf growth, a regression orthogonal test was firstly designed, and the effects of light and temperature on leaf area index of wheat were simulated using APSIM model. The results showed that APSIM model could be used to simulate the LAI of wheat. There was an upward-opening second-degree parabola between wheat LAI and light but a downward-opening one between wheat LAI and temperature. The second-degree parabola between LAI and light was in a decrease, but the light effect was positive when light was not exceeded the critical value, which revealed that a rational increase of light could promote wheat growth under suitable conditions. The temperature effect was positive when the daily temperature was higher than 7.73 ℃, which revealed that a rational increase of temperature could stabilize the wheat LAI at a high value at a certain growing stage. When both light and temperature were increased, the positive effect of light was more significant than that of temperature.