The photosynthesis of rice sheath plays a significant role to furnish rice yield, and it is accounted for 10 to 20% of the final yield. But, limited studies have been done to address this phenomenon and to characteriz...The photosynthesis of rice sheath plays a significant role to furnish rice yield, and it is accounted for 10 to 20% of the final yield. But, limited studies have been done to address this phenomenon and to characterize the mesophyllous cells of rice sheath and how it may attribute to the rice yield. In this paper, super hybrid rice Liangyoupeijiu, its parents Wumang 9311 and Peiai 64S, and hybrid rice Shanyou 63 were studied as the experimental materials, and the characteristics of the mesophyllous cells of rice sheaths were examined by microscopic and super-microscopic observation as well as chlorophyll absorption spectrums. The results showed that rice sheath was rich in the intact mesophyllous cells full of chloroplasts, grana and thylakoids, which were much the same as those of rice blade. The absorption spectrum curves of the Chl. a and b of the sheaths were similar to those of the blades. The stomatal density in the outer epidermises of the sheaths was comparable to those in the up- and down-epidermises of the blades. The significant tests proved that the amount of chloroplast per mesophyllous cell of the sheaths was almost the same as those of the blades, and the mesophyllous cells in the sheaths were also rich in chlorophylls. The chlorophyll content of rice sheath reached about 50% of the chlorophyll content of rice blade, and the P, of the sheath/the blade ranged from 13.60 to 34.57%. Therefore, rice sheath was also full of the intact photosynthetic apparatus similar to those in rice blade, and had capabilities of photosynthesis. The statistical analysis revealed that the physiological senescence of the photosynthetic apparatus in both the sheath and the blade of Liangyoupeijiu was significantly slower than those of the other varieties at the late stages. The profuse grain-filling stage was an inflexion point of the physiological senescence of the chloroplasts and the chlorophylls of both the blades and the sheaths.展开更多
Development of hybrid rice is an important strategy to increase yields of irrigated rice in China. Day length is a highly important environmental factor for hybrid rice adaptability, productivity and quality. Heterosi...Development of hybrid rice is an important strategy to increase yields of irrigated rice in China. Day length is a highly important environmental factor for hybrid rice adaptability, productivity and quality. Heterosis of hybrid rice has been utilized under natural- （long） day length conditions in the middle and lower reaches plain of Yangtze River Valley in China for a long time. However, whether the hybrid rice can show heterosis under short-day length conditions is unknown. In this study, we analyzed plant height, grain number per panicle, and other yield related traits of hybrid rice Liangyoupeijiu （LYP9） and its parents （Pei＇ai 64S and 93-11） under natural- and short-day length conditions and compared the respective heterosis. Results showed that earlier heading, reduced plant height, and reduced grain number per panicle were found in these three varieties under short-day length conditions relative to those under natural-day length conditions. In either natural- or short-day length conditions, heterosis of LYP9 was mainly displayed in grain number per panicle and plant height. This study may help in breeding and selectina suitable hybrid rice for different re qions with natural- or short-day length.展开更多
基金supported by the National Natural Science Foundation of China (30670790)the Project of Science & Technology Department of Hunan Province, China (2007FJ4139)
文摘The photosynthesis of rice sheath plays a significant role to furnish rice yield, and it is accounted for 10 to 20% of the final yield. But, limited studies have been done to address this phenomenon and to characterize the mesophyllous cells of rice sheath and how it may attribute to the rice yield. In this paper, super hybrid rice Liangyoupeijiu, its parents Wumang 9311 and Peiai 64S, and hybrid rice Shanyou 63 were studied as the experimental materials, and the characteristics of the mesophyllous cells of rice sheaths were examined by microscopic and super-microscopic observation as well as chlorophyll absorption spectrums. The results showed that rice sheath was rich in the intact mesophyllous cells full of chloroplasts, grana and thylakoids, which were much the same as those of rice blade. The absorption spectrum curves of the Chl. a and b of the sheaths were similar to those of the blades. The stomatal density in the outer epidermises of the sheaths was comparable to those in the up- and down-epidermises of the blades. The significant tests proved that the amount of chloroplast per mesophyllous cell of the sheaths was almost the same as those of the blades, and the mesophyllous cells in the sheaths were also rich in chlorophylls. The chlorophyll content of rice sheath reached about 50% of the chlorophyll content of rice blade, and the P, of the sheath/the blade ranged from 13.60 to 34.57%. Therefore, rice sheath was also full of the intact photosynthetic apparatus similar to those in rice blade, and had capabilities of photosynthesis. The statistical analysis revealed that the physiological senescence of the photosynthetic apparatus in both the sheath and the blade of Liangyoupeijiu was significantly slower than those of the other varieties at the late stages. The profuse grain-filling stage was an inflexion point of the physiological senescence of the chloroplasts and the chlorophylls of both the blades and the sheaths.
文摘Development of hybrid rice is an important strategy to increase yields of irrigated rice in China. Day length is a highly important environmental factor for hybrid rice adaptability, productivity and quality. Heterosis of hybrid rice has been utilized under natural- （long） day length conditions in the middle and lower reaches plain of Yangtze River Valley in China for a long time. However, whether the hybrid rice can show heterosis under short-day length conditions is unknown. In this study, we analyzed plant height, grain number per panicle, and other yield related traits of hybrid rice Liangyoupeijiu （LYP9） and its parents （Pei＇ai 64S and 93-11） under natural- and short-day length conditions and compared the respective heterosis. Results showed that earlier heading, reduced plant height, and reduced grain number per panicle were found in these three varieties under short-day length conditions relative to those under natural-day length conditions. In either natural- or short-day length conditions, heterosis of LYP9 was mainly displayed in grain number per panicle and plant height. This study may help in breeding and selectina suitable hybrid rice for different re qions with natural- or short-day length.
