科研之友
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摘要
Vast rainfed lowland areas in Asia periodically experience flash floods that adversely affect the survival and productivity of rice (Oryza sativa L.). Progress has been made in developing tolerant germplasm, but fewer efforts have been devoted to developing proper management options for flood-prone areas. The effects of silica application (600 kg SiO(2) ha(-1)) in soil 1 d before sowing on the growth and survival of 21-d-old seedlings submerged for 12 d were evaluated in two experiments. Four contrasting cultivars, tolerant IR49830-7-1-2-3 and Swarna-Sub1 and intolerant IR42 and Swarna, were used. Dry weight, chlorophyll concentration, shoot length, and non-structural carbohydrates were measured before and after complete submergence, and survival was determined 21 d after de-submergence. Survival of all genotypes decreased substantially in Si-treated seedlings, with the tolerant genotypes showing consistently higher survival. No significant interaction was observed between Si treatment and genotypes varying in tolerance of flooding. Si-treated seedlings had lower root dry weight and root-shoot biomass ratio, and greater chlorophyll concentration before submergence. Greater shoot elongation and higher reduction in levels of chlorophyll and non-structural carbohydrate concentrations during complete submergence and greater chlorophyllase activity 1 d after de-submergence were observed in Si-treated seedlings than in the control, and similarly in the sensitive genotypes than in tolerant ones. Survival was negatively correlated with chlorophyll degradation, extent of non-structural carbohydrate depletion, and shoot elongation during submergence. Apparently, excessive Si application in soil 1 d before sowing has negative consequences on seedling growth and survival after complete submergence at vegetative stage in rice.
- 出版日期2011-8
- 单位中国水稻研究所
