Effect of Low Light During Vegetative Stage on Photosynthesis and Growth Attributes in Rice

Eight cultivars of rice were studied under normal (60–70 klux) and low (about 20 klux) light intensities to understand the changes in various morphophysiological characters. Under low light conditions the dry matter, photosynthetic rate, relative growth rate (RGR), net assimilation rate (NAR) and specific leaf weight (SLW) were reduced whereas height, leaf area, leaf area ratio (LAR) and relative leaf growth rate (RLGR) were increased. Dry matter production under low light was impaired through reduced photosynthetic rate despite an increase in chlorophyll content. Cultivars like Ptb. 10 and T. 141 possessing higher photosynthetic rate and NAR, greater chlorophyll content and thicker leaves (SLW) inspite of enhanced RLGR, appear to adapt better under low light.