以不同品种的小麦为材料，同时测量小麦生长过程的光谱反射率和光能利用率，研究了小麦整个生长期内光化学反射指数和光能利用率之间的关系变化，讨论二者之间关系的时间效应.实验结果表明，对小麦的整个生长期，光化学反射指数并不能作为估算光能利用率的一个有效指数.由于叶片叶绿素含量和叶面积指数的影响，在小麦的生长初期和末期，光化学反射指数和光能利用率之间的相关性不高，相关系数R2分别为0.222 4和0.210 6.对于小麦生长力旺盛的阶段，光化学反射指数可以作为估算光能利用率的一个可行方法，能够获得一定准确度的光能利用率，相关系数R2分别为0.612 7、0.641 2和0.601 1.

Different types of wheat were selected to study the time effect on relationship between photochemical reflectance index and light use efficiency in the whole growth duration.The results prove that photochemical reflectance index is not a feasible index of light use efficiency in the growth duration of wheat.There is not an obvious relationship between photochemical reflectance index and light use efficiency in the early and mature stage of wheat because of influences of chlorophyll contents and leaf area index; regression coefficients R2 are 0.222 4 and 0.210 6 respectively.For the stages with maximum growth capabilities,photochemical reflectance index has provided a reliable method in estimating light use efficiency with regression coefficients R2 of 0.612 7,0.641 2 and 0.601 1 respectively.Therefore,other parameters should be introduced to improve the feasibility of PRI and enhance the precision of LUE estimation.