Study On Differences Of Carbon And Nitrogrn Metabolism In Different Genotype Maizes

ABSTRACT In order to find maize carbon and nitrogen metabolism and the theory principle which can increase yield and quality of it, we adopted field tester to study on accumulation and transfer rules of total nitrogen , protein nitrogen, soluble sugar and starch in the four maize cultivars stem , leaf and grain which grow in same growing conditions. We compared the inference of grain,yield dry matter accumulation, photosynthetic rate, chlorophyll contents of leaves. The main results were as follows :1. The nitrogen metabolism is vigorous and the carbon metabolism is feeblish in Yudan 2002 . The carbon metabolism is vigorous and the nitrogen metabolism is feeblish in Xundan 20. The coordinating activity of the carbon and nitrogen metabolism in Zhengdan 958 is better,but the carbon metabolism about it is a little more vigorous. The coordinating activity of the carbon and nitrogen metabolism in Nongda 108 is better,and both of them are vigorous.2. Yudan 2002:The leaf chlorophyll content of it declined faster after silking,and more nitrogen and protein-N in leaf transfer to grain in this time. Nitrogen supplying capacity to grain of root is strong during later grouth stage. Nitrogen and protein-N content are higher during the whole growth. The nitrogen harvest index in harvest time is higher. Photosynthesis speed of leaf is lower in filling stage. The starch content and C/N rate of stem,leaf and grain are all lower in harvest time.3. Xundan 20: The ability of photosynthate in vegetative organs transfering to grain is strong. The harvest index is higher. The ability of soluble sugar changing to starch in grain is stronger. The starch content in grain is higher ,the nitrogen content is lower and C/N rate in all organs is higher in harvest time. Nitrogen supplying capacity to grain of root is feeblish during later grouth stage and it is sensitive to nitrogen. If the nitrogen fertilization supply is lack,a great deal of the nitrogen in leaf and stem would transfer to grain ,so the leaf would be early aging , the stem would be lodging easily,and the yield woule be decrease.4. Zhengdan 958:The time of the leaf holding green is long,the photosynthetic efficiency is higher and the balance of source and sink is better. The starch content in grain is higher , the nitrogen content is lower and the C/N rate in all organs is higher in harvest time. The nitrogen transfering to grain in the vegetative organs is few. If nitrogen fertilization supply is lack during later grouth stage ,the nitrogen in the stem would transfer to grain first,and the bility of photosynthesis in leaf would be holding.5.Nongda 108: The time of the leaf holding green is long,LAI decreases slower, photosynthesis speed of leaf is higher and be keeping long time,but the photosynthetic efficiency is lower. The weight of dry matter accumulation were large ,but dry matter weight of stem and leaf decrease earlier,so the balance of source and sink is weak. The nitrogen content in the stem and leaf are higher, the nitrogen supplying capacity to grain of root is feeblish during later grouth stage,but the nitrogen transfering to grain in the vegetative organs is more. The nitrogen content of grain and C/N rate are all medium level.