中文摘要：

在土培条件下,选用氮高效水稻品种扬稻6号和氮低效水稻品种农垦57和日本晴,比较了它们的旗叶在开花期、灌浆期和成熟期的叶绿素含量、净光合速率(Pn)、可溶性蛋白含量、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性和MDA含量变化,以及氮积累量、产量与氮效率的差异。结果表明:氮高效品种扬稻6号在生育后期旗叶叶绿素含量和Pn较高,灌浆期氮积累量比日本晴和农垦57高16%和25%,氮转移率比较恒定,CAT和POD活性较高,MDA含量较低,衰老较慢。氮低效品种日本晴和农垦57的旗叶氮转移率下降较快,灌浆期各为34%和35%,成熟期则下降到16%和19%;Pn和抗氧化酶活性下降较快,趋于早衰。可见扬稻6号旗叶延缓衰老对于促进水稻籽粒灌浆,维持氮高效十分重要。

英文摘要：

Pot experiments were conducted to investigate the changes of chlorophyll content,net photosynthetic rate(Pn),N content,soluble protein(SB)content,catalase(CAT)activity,peroxidase(POD)activity and malondialdehyde(MDA)content among Yangdao 6,Nongken 57 and Nipponbare in flowering stage,grain filling stage and maturing stage.We found that the flag leaves of Yangdao 6 could stay green longer and maintain higher at Pn and soluble protein content.Furthermore,N content in Yangdao 6 flag leaves was 16% and 25% high...