| Rice, as one of the three major cereal crops, is largest crop of China, perennial planting area over the0.267million hectares, accounting for nearly30%of the grain sown area, total grain production accounts for nearly40%.(China Rural Statistical Yearbook2005). And more than half population of China, rice is the staple food. Therefore, rice production is related to food security of China, rice yield, high yield research cannot be ignored.so that the rice production to achieve the successful cultivation of rice and hybrid rice research after the success of the third leap. China launched a "super rice breeding programs implemented by the Ministry of Agriculture. China’s rice production after the third leap in the success of the success of hybrid rice research Following the dwarf rice cultivation. Jiangsu as the main producing provinces of the rice growing regions in the middle and lower reaches of the Yangtze River,80percent of the acreage of japonica rice. District of the rice paddy in the jointing stage often encounter low-intensity continuous rain, and the booting stage encountered by high-light high-temperature environment, especially the late growth stage low temperature under strong light, easy to premature aging affect grain plumpness, so the performance of the inter-annual yield was not stable. Therefore, the production potential of high-quality high-yielding japonica varieties in Jiangsu Province to play relies heavily on its light and temperature adaptability. Photooxidation of Jiangsu Province rice, to ascertain the mechanism of high yield, optimize cultivation measures and accelerate the demonstration and extension of the varieties of great significance, so we selected eight typical high-yielding varieties of Jiangsu, where late maturing japonica including Nanjing45(super rice), Wuyujing3(japonica control),02102, Wuyunjing7late japonica,(late japonica control), Nanjing74142, Nanjing44(super rice) and Nanjing5055, maturing japonica rice, including Nanjing46, respectively, in the field and pot conditions, study their photosynthetic physiological characteristics, the results are as follows:1The physiological characteristics of Nanjing44under field conditions:In the field we choose the super japonica rice Nanjing44high-yielding of photosynthetic characteristics in Jiangsu China. Under field conditions, with Japonica rice(Nanjing46,Nanjing5055) and Japonica rice(Wuyunjing7) as control. In a critical period-before and after flowering of rice production we measured different organs of different varieties of dry matter accumulation and transformation properties of maturing stages, photosynthesis, soluble protein, antioxidant enzyme activities and Chlorophyll fluorescence of reciprocal first leaf were analyzed. The results showed that, In field conditions, In the critical period-booting and grain filling stage of japonica production of Nanjing44, the function leaves (Source) have a relatively high net photosynthetic rate(Pn). And less photoinhibition of photosynthesis at noon in a day,"lunch" is not obvious. And with a stable net photosynthetic rate in the late growth stage, has a strong ability to adapt light in the whole growth period is the intensity of the wide amplitude. It is useful to formation more spikes, each panicle (large Sink) and start grain filling faster. In the transformation of photosynthetic products, its high output rate of the material stems and stems biomass conversion rate (Flow), is conducive to photosynthetic products accumulate in the grain, got a higher seed setting rate and grain weight; In the late growth stage it still maintain a high soluble protein content, leaf antioxidant ability, help to clear peroxidation products MDA, and has less attenuation function of chlorophyll, photosynthesis to keep more stable and longer filling time, these all are stable and high yield physiological basis of photosynthesis of Nanjing44.2The physiological characteristics of Nanjing45under field conditions: With"Wuyujing3,108"as control,have a study in transplanted field about super-high-yielding Nanjing45that is early harvest late Japonica rice in the field, in different nitrogen (150.0kg.hm-2:LN、300.0kg.hm"2:MN、375.0kg/.hm-2:HN) at tillers stage, jointing Stage and post-flowering growth and photosynthetic performance and the tolerance to photooxidation and shading characteristics.Also research the yield components in heading stage. The results showed that, as compared with Wuyujing3,108, Individual plant yield of Nanjing45have increase24.89%,5.4%at MN respectively. Also in growth period and different nitrogen application, it got a better photosynthetic capacity. Particularly, Pn of Nanjing45was increased by8.33%,8.56%,2.33%;After photooxidation treatment, Fv/Fm in Nanjing45decreased less. Under shading treatment, Seed setting rates and dry matter accumulation decreased less. The photosynthetic traits and applicability mentioned above may be an important physiological basis for high yield in Nanjing45.It should be noted that formation of rice yield was significantly related to their photosynthetic capacity during30d after flowering. So it could also be a reliable physiological yield potential of rice.3Physiological basis of different material in different nitrogen of high yielding japonica rice:The conditions in the pot experiments, with super rice Nanjing44and Nanjing45,choose three middle Japonica rice(Wuyujing3,Nanjing45,02102) and five late Japonica rice(Wuyunjing7,Nanjing44,Ning74142,Nanjing46,Nanjing5055) at maturing stages, photosynthesis, soluble protein and antioxidant enzyme activities of reciprocal first leaf were analyzed in different nitrogen fertilizations(150.0kg.hm-2:LN-.300.0kg.hm-2: MN、450.0kg.hm-2:HN).We analyze the different nitrogen application in their photosynthesis and yield formation under physiological mechanisms. The result show that from the perspective of photosynthesis, while at high CO2concentration, the Jiangsu rice varieties in the low nitrogen or medium nitrogen conditions, can improve their photosynthetic CO2saturation point, with high photosynthetic rate; The amount of nitrogen increased the ability to use high light intensity, in particular, can relieve yellowing leaves and premature aging due to higher activity of antioxidant enzymes under the low temperature and high light conditions during the maturing stages... |
PDF Full Text Request