Abstract: For building a pattern of high yield, high efficiency and water-saving planting technology of rice, a split-plot design experiment was conducted to explore the influences of interaction between nitrogen and density on photosynthetic characteristics and the yield of the late rice Fengyuanyou 299. Significant differences between net photosynthetic rate, conductance to H₂O, intercellular CO₂ concentration and transpiration rate of different nitrogen and density in rice leaf were showed and the highest photosynthetic rate was observed at the tillering stage. The net photosynthetic rate at tillering stage and milky stage both showed the highest parameters when the amount of nitrogen fertilizer was 180 kg/hm², and had about 6.43%-10.01% and 3.92%-70.51% higher than other treatments respectively. Tillering stage net photosynthetic rate reduced linearly with increasing density, and had about 5.04%-6.73% lower than other treatment at the planting density of 300 thousand/hm² points, there were no significant differences at booting stage and milky stage, and the higher density was responsible for the stronger net photosynthetic rate at the heading, the regularity of net photosynthetic rate had significantly lower about 4.45%-7.97% in the low-density processing than in the high-density processing. The trends of its dynamic performance showed as follows:The net photosynthetic rate was increased at first, then decreased and reduced eventually; conductance to H₂O was declined at first and then ascended; the intercellular CO₂ concentration was increased at first, then reduced and elevated after that; transpiration rate was declined straightly. The results showed that a positive correlation had existed between economic yield and the photosynthesis in the early rice and the late rice growth stages, especially had extremely significant correlation at the late growth stage and had negative correlation at the mid growth stage of the rice respectively. So it's an important way to improve the economic yield of rice by building a reasonable regulation of nitrogen and density, improving the photosynthesis in the early and late growth of rice and keeping the photosynthesis in the mid growth stage of rice.

Key words: Water saving irrigation, Photosynthetic traits, Interactive of nitrogen and density, Rice, Grain yield

CLC Number: 

• S141.1

• S511.01