Impact of high temperature stress on photosynthetic characteristic and yield of rice (Oryza sativa) at heading
2012
XIE, XIAO JIN | LI, BIN BAI | SHEN, SHUANG HE
To estimate impact of high temperature stress on photosynthetic characteristic and yield in rice (Oryza sativa L.), a pot experiment was conducted during 2008 in environment-controlled chambers with two rice cultivars (Yangdao 6 and Nanjing 44) under high temperature stresses (35°C/3d, 35°C/5d, 39°C/3d and 39°C/5d) at heading. The results showed that rice grain yield, chlorophyll content, net photosynthetic rate (NPn), superoxide dismutase content (SOD) and leaf area index (LAI) presented a sharply decline, and the relative conductivity, malondialdehyde content (MDA) increased gradually with the elevation of stress temperature and extension of stress time. The increasing rate (reduction rate) of some physiological and biochemical indexes in Yangdao 6 were lower than that in Nanjing 44 compared with the CK under the same temperature stress. It was showed that response of Nanjing 44 to high temperature was stronger than that of Yangdao 6. In accordance with correlation analysis, the rice grain yield showed a positive correlation with NPn and LAI (P<0.01), and the correlation coefficients of them were 0.93 and 0.89 respectively. Further, the correlation between rice grain yield and DW after early stage of maturing, the export percentage of the matter in stem-sheath (EPMSS) and the transformation percentage of the matter in stem-sheath (TPMSS) were not significant. It was showed that rice grain yield under high temperature stress originated mainly from leaves photosynthesis and LAI after heading.
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