Effects of Nitrogen Form and Water Stress Interaction on Photosynthesis,Utilization of Water and Nitrogen of Rice Plants at the Tillering Stage

By using the method of nutrient solution culture and simulated water stress (by adding PEG6000), the effects of different nitrogen forms (NO_3~-, NH_4~+, and the ratio of NO_3~- to NH_4~+ is 50∶50) and water stress interaction on nitrogen use efficiency and the characteristics of nitrogen consumption of rice plants at the tillering stage were studied. Under non-water stress, the increased biomass of rice plants under the mixed supply of nitrate and ammonium was higher than that under the other two sole nitrogen supply. However, under water stress, the increased biomass of rice plants under sole ammonium supply was the highest. The photosynthetic rate, nitrogen use efficiency and water use efficiency of rice plants supplied with sole ammonium were higher than those of the other two treatments under the two water regimes. Furthermore, under the mixture supply of nitrate and ammonium, nitrate consumption was higher than ammonium consumption of rice plants at the tillering stage regardless of water regimes.