Low light stress: mechanism of tolerance and screening method
1991
Cabuslay, G.S. | Vergara, B.S. | Quintana, R.U. (International Rice Research Inst., Los Banos, Laguna (Philippines))
A study was done using 14 rice cultivars to determine the mechanism of tolerance of rice to shading at seedling stage and to propose a screening method. Seedlings were grown in a phytotron glasshouse for two weeks and then shaded with abaca cloth for another two weeks by allowing 50 percent and 20 percent of full sunlight to pass through. An unshaded control was also grown. Shading reduced total plant weight in both treatments. Average reduction per cultivar was 34.13 percent when plant were grown under 50 percent of full sunlight while reduction was 68.92 percent when plants were grown under 20 percent light. Kurkaruppan had the least reduction in shoot weight both at 50 percent and 20 percent light. At 20 percent light, shoot weight reduction was highly correlated with reductions in plant height (r = 0.70** ), leaf number (r = 0.70** ) and in leaf area (r = 0.84** ). Results suggest that plants tolerate low light by leaf elongation thereby increasing plant height, leaf number and leaf area to be able to trap available light. Change in plant height, being nondestructive and less laborious could be an index for selection for low light, being nondestructive and less laborious could be an index for greenhouse for low light tolerance. Based on this, a screening method which can be done in the greenhouse was proposed
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