氮素水平对不同穗型水稻品种植株衰老和产量的影响

在大田条件下，研究了两种氮素水平对直、弯穗水稻品种植株生长、叶片衰老和产量的影响。结果表明，高氮条件下两品种的朱粗度和叶片性状均优于低氮条件。增施氮肥能提高剑叶的叶绿素含量，延长叶绿素含量缓降期，使植株在生育后期能保持较高的绿叶面积；同时能提高剑叶的全氮含量，延长光合速率高值持续期，增加植株的干物质积累和籽粒产量。在同一氮素水平下，直立穗型品种的植株粗度、剑叶活力、籽粒灌浆速率、千粒重、生物产量及籽粒产量均略优于弯曲穗型品种。

Effect of Different N-level on Plant Senesecence and Grain Yield of Rice Varieties with Different Panicle Types

Effect of two different levels of soil N-fertilizer on plant growth, leaf senescence and grain yield of erect-panicle and curved-panicle rice varieties were studied under field conditions. The results revealed that diameter in stem base and panicle neck and leaf characters of two rice varieties were better in high-N level than in low-N one. Application of N-fertilizer could inceas chlorophyll content of flag leaf, prolong its relative steady phase (RSP) of chlorophyll content and keep higher leaf area during grain-filling stage. Also there were higher total-N content of flag leaf and longer photosynthetic active duration. Eventually it increased plant dry matter accumulation and grain yield. Under the same N-level, diameter in stem base and panicle neck, activity of flag leaf, grain filling rate, 1000-grain weight, biomass and grain yield were basically better in erect-panicle variety than that in curved one.