光、氮及其互作对超级粳稻产量和氮、磷、钾吸收的影响

大田条件下以超级粳稻南粳44和宁粳3号为材料, 设置2种氮肥水平(N10: 150 kg hm^-2, N20: 300 kg hm^-2)和3种遮光处理(L1: 不遮光, L2: 抽穗前遮光20 d, L3: 抽穗后遮光20 d), 研究光、氮及其互作对超级粳稻产量和氮、磷、钾吸收的影响。结果表明, 同一氮肥水平下产量呈现L1>L3>L2。其中, L2使植株在拔节至抽穗阶段及抽穗期的氮、磷、钾积累量显著下降, 主要由于L2显著降低了抽穗前期的根系α-NA氧化量及根干重, 导致根系吸收养分能力下降, 最终产量显著低于L1, 达30.58%~35.26%。L3使植株在抽穗至成熟阶段及成熟期的氮、磷、钾积累量显著下降, 主要由于L3显著降低了抽穗后期的根系α-NA氧化量及根干重。尽管在抽穗后随着植株根系逐渐衰老及机能下降, L3对根系、养分吸收及最终产量的影响要小于L2, 但最终产量依然显著低于L1, 达10.91%~18.47%。L2和L3条件下, 随着氮肥水平增加, 植株根系α-NA氧化量及根干重显著增加, 导致拔节至成熟期各阶段的氮、磷、钾积累量显著增加, 最终产量及氮肥利用率显著提高。由此可见氮肥施用能部分弥补弱光逆境对超级粳稻氮、磷、钾吸收及产量的影响。

Effects of Light,Nitrogen and Their Interaction on Grain Yield and Nitrogen,Phosphorus and Potassium Absorption in Japonica Super Rice

A field experiment was conducted using japonica super rice Nanjing 44 and Ningjing 3 with two nitrogen fertilization levels (N10: 150 kg ha^-1, N20: 300 kg ha^-1) and three shading treatments (L1: no shading, L2: shading 20 days before heading, L3: shading 20 days after heading) to study theeffects of light, nitrogen and their interaction on grain yield and NPK absorption. Results showed that yield under the samelevel of nitrogen fertilizer was L1>L3>L2. Compared with L1, L2 significantly reduced NPK accumulation from jointing to heading and at whole heading stage, mainly due to the significant decrease of the root oxidation ability of α-NA and root dry weight before heading, resulting in decreased root nutrient uptake capacity and the final yield decrease of 30.58%–35.26%. L3 significantly reduced NPK accumulation from heading to maturity and at whole maturity stage, mainly due to the significant decrease of the root oxidation ability of α-NA and root dry weight after heading. Although the root was gradualaging with the function declining after heading, resulting in the reducedeffect onroot system, nutrient absorptionand yield in L3 than in L2, the final yield was still 10.91%–18.47% lower in L3 than in L1. Under L2 and L3 conditions, with increasing nitrogen level, the root oxidation ability of α-NA and root dry weight increased significantly, resulting in that NPK accumulation increased significantly in various stages from jointing to maturity, then the final yield and nitrogen use efficiency improved significantly. This indicated that nitrogen fertilizer could partially offset the impact of low light stress on NPK nutrient absorption and grain yield in japonica super rice.