光、氮及其互作对超级粳稻产量和物质生产特征的影响

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物质生产特征的影响。结果表明,较之L1,L2不仅减少了有效穗数和每穗粒数,导致总颖花量下降,降幅达24.81%~35.63%,而且还显著降低了抽穗期茎蘖数和叶面积指数,降幅达2.90%~6.44%和19.02%~27.17%,导致抽穗至成熟阶段的光合势、干物质积累量显著下降,最终产量显著下降,降幅达27.23%~35.26%。较之L1,L3主要影响了抽穗至成熟阶段的光合物质积累,导致结实率和千粒重显著下降,降幅达1.49%~4.48%和5.54%~9.17%,最终产量显著下降,降幅达10.91%~18.47%。L2条件下,随着氮肥水平增加,抽穗期茎蘖数与叶面积指数均显著增加,导致抽穗至成熟阶段光合势、干物质积累显著增加,最终有效穗数、每穗粒数、总颖花量以及产量显著提高。L3条件下,随着氮肥水平增加,抽穗至成熟阶段的光合物质积累显著提高,其中茎叶干物质向穗部转运量显著增加,转运率和贡献率也进一步提高,最终产量显著提高。由此可见氮肥施用能部分弥补因弱光逆境对超级粳稻物质生产及其产量的影响。

Effects of Light,Nitrogen and Their Interaction on Grain Yield and Matter Production Characteristics of Japonica Super Rice

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 matter production. Results showed that, compared with L1 treatment, L2 not only reduced the effective panicles and grains per panicle, resulting in the decline of total spikelets by 24.81% to 35.63%, but also significantly reduced the tiller number and leaf area index at heading by 2.90%–6.44% and 19.02%–27.17% respectively, causing photosynthetic potential, dry matter accumulation decreased significantly from heading to maturity, and at last the final yield decreased by 27.23%–35.26%. Compared with L1 treatment, L3 mainly affected photosynthate accumulation from heading to maturity, leading to seed setting rate and grain weight significantly decreased by 1.49%–4.48% and 5.54%–9.17% respectively, and the final yield decreased by 10.91%–18.47%. UnderL2 condition, with increasing nitrogen level, tiller number and leaf area index at heading increased significantly, resulting in photosynthetic potential, dry matter accumulation increased significantly from heading to maturity, and the ultimately effective panicles, number of grains per panicle, total number of spikelets and the yield improved significantly. Under L3 condition, with increasing nitrogen level, photosynthate accumulation from heading to maturity increased significantly, dry matter translocation from stems and leavesto the panicle increased significantly, meanwhile, translocation rate and contribution rate were further improved, and the ultimate yield improved significantly. This indicated that nitrogen fertilizer could partially offset the impact of low light stress on the matter production and yield of japonica super rice.