Abstract: Employing two rice varieties with different amylose content as test materials, this paper studied the effects of early stage (from transplanting to spikelet differentiation) shading on the function leaf growth at grain-filling stage and on the grain quality of rice. The results showed that early stage shading obviously increased flag leaf area, and promoted the carbon and nitrogen metabolism of function leaves. The shading effects on amylose accumulation varied with varieties, but those on protein accumulation were the same (a marked decrement of protein content). The brown rice rate declined but did not reach significant level, milled rice and chalky rate decreased extremely significantly, head rice rate and amylose content increased significantly or extremely significantly, while grain length and width and protein content did not have significant changes.

Key words: Environmental carrying capacity, Quantificational method, Perspective