Abstract:A field experiment with a low nitrogen efficiency rice variety (Wuyujing3, WY3), a high nitrogen absorption efficiency rice variety (Lianjing7, LJ7) and a high nitrogen absorption and utilization efficiency rice variety (Nanjing 9108, NJ9), was conducted under three conditions including no nitrogen (LN), moderate or reduced nitrogen fertilizer input (MN, 200 kg/hm2) and excessive nitrogen application (HN, 350 kg/hm2). The response of nitrogen contents in the whole rice plant and key function leaf to nitrogen application and the effect of this change to photosynthetic characteristics and nitrogen use efficiency were explored. The results showed that the dry matter and nitrogen accumulation of nitrogen efficient varieties were stronger than that of nitrogen inefficient varieties at the late growth stage. Under MN condition, dry matter accumulation of LJ7 and NJ9 from full heading stage to mature stage increased by 46.44% and 29.12% respectively while nitrogen accumulation increased by 26.28% and 32.31% respectively compared with that of WY3 during the same stage. Meanwhile, under the MN condition, nitrogen concentration decreased by 21.86% in WY3 flag leaves during 27days after applied the heading stage top-dressing (grain filling stage), and decreased by 26.3% and 34.74% respectively in LJ7 and NJ9 flag leaves, the order of decreasing range was NJ9>LJ7>WY3. Dry weight, photosynthetic rate (Pn) and stomatal conductance (Gs) of the flag leaves, weight per panicle and yield of LJ7 and NJ9 were significant different compared with these of WY3, and the nitrogen use efficiency of nitrogen efficient varieties was higher than that of WY3. Under HN condition, dry matter and nitrogen accumulation of LJ7 and NJ9 were still higher than that of WY3 during the grain filling stage, dry weight and Gs of the flag leaves, weight per panicle were higher than these of WY3. Meanwhile, under the same condition, the decreasing range of nitrogen concentration in flag leaves was NJ9>WY3>LJ7. Pn, panicle number and yield of LJ7 were lower than these of NJ9 and WY3. There was no significant difference about nitrogen harvest index (NHI) among different varieties. As a nitrogen strong absorption variety, high recovery nitrogen use efficiency (REN) of LJ7 led to its sensitivity to high nitrogen input, its physiological nitrogen use efficiency (PEN) and agronomic nitrogen use efficiency (AEN) were lower than these of WY3 and NJ9. Therefore, under the moderate or reduced nitrogen application conditions, nitrogen efficient varieties have strong capacity of photosynthate transportation, and the yield and nitrogen use efficiency are optimal. Under the condition of excessive nitrogen application, high nitrogen absorption efficiency variety has a weak tolerance to nitrogen application rate, photosynthate transportation and nitrogen use efficiency are lower than other varieties in this test.