基于高氮投入和基因型差异的水稻氮素营养特征

采用氮素低效品种武育粳3(WY3)、氮素吸收高效品种连粳7(LJ7)和氮素吸收利用双高效品种南粳9108(NJ9)，开展了包括不施氮肥(LN)、适宜或减量氮肥投入(MN, 200 kg/hm2)和过量施氮(HN, 350 kg/hm2)三个条件的田间试验，探究了不同基因型差异的水稻植株整体和关键功能叶含氮量对施氮水平的响应，及其导致的光合特征的变化对氮素利用效率的作用特征。结果表明：在生育后期，氮高效品种的干物质和氮素积累强于氮低效品种。在MN条件下，LJ7和NJ9在齐穗期至完熟期干物质积累量相比WY3分别高46.44%和29.12%，氮素积累量分别高26.28%和32.31%；在该条件下，施用穗肥后27 d的时间段内(灌浆阶段)，WY3的剑叶氮含量降低21.86%,LJ7和NJ9的剑叶氮含量分别降低26.3%和34.74%，降幅次序为NJ9>LJ7>WY3,LJ7和NJ9的剑叶干重、光合速率、气孔导度、单穗重和产量显著高于WY3，氮高效品种的氮素利用效率指标优于WY3。在HN条件下，LJ7和NJ9在灌浆阶段的干物质和氮素积累量仍高于WY3，剑叶干重、气孔导度和单穗重显著优...

Characteristics of Nitrogen Nutrition in Rice Based on High Nitrogen Input and Genotype Differences

A field test adapting a low nitrogen efficiency variety (Wuyujing3, WY3), a high nitrogen absorption efficiency variety (Lianjing7, LJ7) and a high nitrogen absorption efficiency variety (Nanjing 9108, NJ9), was conducted under three conditions: no nitrogen (LN), suitable or reduced nitrogen fertilizer input (MN, 200 kg hm_^-2) and excessive nitrogen application (HN, 350 kg hm_^-2). The response of nitrogen content of whole rice plant and its key functions level to nitrogen application and the effect of changes in photosynthetic characteristics on nitrogen use efficiency were analyzed. The results showed that the dry matter and nitrogen accumulation of N efficient varieties were stronger than that of N inefficient varieties at the late growth stage. Under the MN condition, the dry matter accumulation of LJ7 and NJ9 from full heading stage to mature stage was 46.44% and 29.12% higher than that of WY3, and the nitrogen accumulation were 26.28% and 32.31% than that of WY3. At the same treatment, the nitrogen concentration of the flag leaves of WY3 decreased by 25.4% at the filling stage (27d after panicle fertilization), and the nitrogen concentration in the flag leaves of LJ7 and NJ9 decreased by 30.74% and 42.11% respectively, the order was NJ9> LJ7>WY3. The leaf dry weight, Pn, g_s, grain weight per spike and yield of LJ7 and NJ9 were significantly higher than those of WY3, and the nitrogen use efficiency of nitrogen efficient varieties was better than that of WY3. Under the HN condition, the dry matter and nitrogen accumulation of LJ7 and NJ9 in the grouting stage was still higher than that of WY3, the leaf dry weight, g_s and grain weight per spike were significantly better than those of WY3. At the same treatment, the decreasing range of nitrogen concentration in flag leaf was NJ9>WY3>LJ7. Pn, spike number and yield of LJ7 were lower than those of NJ9 and WY3. There was no significant difference in nitrogen harvest index (NHI) among varieties. The nitrogen physiological efficiency (PE_N) and nitrogen agronomic efficiency (AE_N) of LJ7 were lower than those of WY3 and NJ9. It can be seen that under the appropriate or reduced nitrogen application conditions, the nitrogen efficient varieties have strong capacity photosynthate transportation, and the yield and nitrogen use efficiency are optimal. When nitrogen input is high, nitrogen efficient absorbing varieties are sensitive to nitrogen application rate.