氮肥运筹对小麦花后剑叶衰老及籽粒发育的影响

EFFECTS OF NITROGEN APPLICATION METHODS ON FLAG LEAF SENESCENCE AFTER ANTHESIS AND GRAIN DEVELOPMENT IN WHEAT

以扬麦158为试验材料,研究小麦花后剑叶衰老特性及其与胚乳细胞增殖充实关系。结果表明:小麦剑叶衰老过程可划分为3个时期:1功能稳定期(花后0～10d),叶绿素和可溶性蛋白质含量基本稳定,剑叶超氧化物歧化酶(SOD)、过氧化物酶(POD)活性上升,丙二醛(MDA)含量略有上升。2缓衰期(花后10～25d),叶绿素含量下降较快,可溶性蛋白质含量和SOD、POD活性等下降平缓,MDA含量增加较缓慢;群体叶色保持绿色。3速衰期(花后25d至成熟),可溶性蛋白质含量和SOD、POD活性等快速下降,MDA含量增加幅度明显加大,植株衰老进程加快;剑叶SOD、POD活性高且下降缓慢,MDA含量低且增加缓慢的处理,其胚乳细胞数多,粒重高。氮肥基肥与追肥施用比例为5∶5时,可有效延长剑叶功能期,提高粒重。

The senescence characteristics of flag leaves after anthesis and their relationship to the development of grains in wheat (Triticum aestivum L. cv. Yangmai 158) were studied in Agricultural College of Yangzhou University from 1995-1997. The processes of flag leaf senescence could be divided into three periods, ie function stable, slowsenescence and fastsenescence phases. During the slowsenescence phase (the 10th to 25th day after anthesis), chlorophyll content declined quickly, soluble protein content, SOD and POD activities declined slowly, and MDA content increased slowly too. Leaves in population remained green. During the fastsenescence phase (from the 25th day after anthesis to maturity), soluble protein content, SOD and POD activities declined quickly, and MDA contents increased significantly. Plant senescence rate became very fast. The treatment of basal∶top dressing N 5∶5, with low MDA content and high SOD, POD activities could result in more endosperm cells and heavier grain weight.