许多研究者认为:在一定的太阳能量下,水稻有一个获得最大干物质量的最适宜的叶面积系数(LAI)。去年我们测定了改良印度矮秆型品种IR8和高秆型品种皮塔(Peta)的叶面积系数。但是,由于缺乏精确的叶面积系数资料,因而我们根据叶面积系数与干物质积累之间一般为抛物线的相关关系推测了最适叶面积系数〔1968年年报〕。另外一些作物,如牧草,虽然没有最适叶面积系数,但临界叶面积系数是存在的。超过这个系数,干物质的积累并不随叶面积系数增大而增加。因为叶面积系数对干物质生产和产量有很重要的关系,因此,我们力求进一步弄清最适 Many researchers believe that under certain solar energy, rice has the most suitable leaf area index (LAI) for maximum dry matter. Last year, we measured leaf area coefficients for improved Indian short stalk type IR8 and high stalk type Peta. However, due to the lack of accurate LAI data, we estimated the LAI based on the generally parabolic correlation between LAI and dry matter accumulation [1968]. Other crops, such as pasture, although there is no optimal leaf area coefficient, but the critical leaf area coefficient exists. Above this coefficient, dry matter accumulation did not increase with increasing leaf area coefficient. Because the leaf area coefficient has an important relationship with dry matter production and yield, we sought to further clarify the optimal