Reexamination of silicon effects on rice growth and production under field conditions using a low silicon mutant
- 735 Downloads
Silicon (Si) is a beneficial element for healthy growth and high and sustainable production of rice, but the mode of action of the beneficial effects has not been well understood. We carried out field trials for four years at two different locations to re-examine the effects of Si on the growth and production of rice using a low silicon rice (lsi1) mutant. The mutant accumulated much lower Si at each growth stage compared with the wild-type rice (Oryza sativa L. cv Oochikara), but there was no difference in the accumulation of other nutrients including N, P, and K. Measurements at different growth stages showed that low Si in the mutant hardly affected the tiller number, chlorophyll content (SPAD value), and root growth. The plant height and shoot dry weight of the wild-type rice were slightly higher than those of the mutant at a later growth stage, but the difference was not significant between the two lines. However, grain yield was reduced by 79–98%, depending on year, due to a low Si accumulation in the mutant, which showed the largest effect of Si on rice production among all studies reported so far. Among the yield components, the percentage of filled spikelets was mostly affected, being only 13.9% of the wild-type rice in the mutant. The grain color of the mutant became brown because of excessive transpiration and infection of pathogens. These results indicate that Si increases rice yield mainly by enhancing the fertility of spikelets.
KeywordsField Growth Mutant Production Rice Silicon Stress
This work is supported by a Grant-in-Aid for Scientific Research on Priority Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan (no. 17078008 to J. F. Ma) and a grant from the Ministry of Agriculture, Forestry and Fisheries of Japan (Rice Genome Project IP-5003 to J. F. Ma). The authors thank lab members for their help in transplanting and harvesting rice.
- Datnoff LE, Rodrigues FÁ (2005) The role of silicon in suppressing rice diseases. APSnet Features February 2005Google Scholar
- Ma JF (2004) Role of silicon in enhancing the resistance of plants to biotic and abiotic stresses. Soil Sci Plant Nutr 50:11–18Google Scholar
- Ma JF, Takahashi E (2002) Soil, Fertilizer, and Plant Silicon Research in Japan. Elsevier Science, AmsterdamGoogle Scholar
- Ma JF, Nishimura K, Takahashi E (1989) Effect of silicon on the growth of rice plant at different growth stages. Soil Sci Plant Nutr 35:347–356Google Scholar
- Sasamoto K (1958) Studies on the relation between the silica content in the rice plant and the insect pests. Part 6. Jpn J Appl Entomol Z 2:88–92Google Scholar
- Seo W, Ota Y (1982) Role of the hull in the ripening of the rice plant. Part 5. Water loss in hull and development of rice kernel. Jpn J Corp Sci 51:529–534Google Scholar
- Takahashi E, Hino K (1978) Silica uptake by plant with special reference to the forms of dissolved silica. J Sci Soil Mature Jpn 49:357–360Google Scholar
- Takahashi E, Arai K, Kashida Y (1966) Studies on the physiological role of silicon in corp plant. Part 14. J Sci Soil Mature Jpn 37:594–598Google Scholar
- Yoshida S (1965) Chemical aspect of silicon in physiology of the rice plant. Bull Natl Agric Sci B 15:1–58Google Scholar