追氮时期对超高产冬小麦旗叶和根系衰老的影响

采用水泥池栽培和田间土柱栽培相结合，研究了超高产条件下追氮时期对冬小麦旗叶和根系衰老及产量的影响。结果表明，拔节期较起身期追施氮肥提高了旗叶和根系开花后的活性氮清除能力，降低了膜质过氧化水平，提高了ｉＰＡｓ的含量，减少了ＡＢＡ的积累，延缓了旗叶光合能力和根系活力的下降，提高了籽粒生长速率，从而增加了粒重和产量。

Effects of Nitrogen Topdressing Stage on the Senescence of Flag Leaves and Roots in Winter Wheat under Super-high-yielding Level

Effects of nitrogen topdressing stage on flag leaves and roots senescence and grain yield of winter wheat under super-high-yielding level were studied by combined experi ments of trough culture and soil colum culture. The results showed that compared with nitrogen topdressing at double ridged stage (treatment 1) , nitrogen topdressing at jointing stage (treatment 2) improved the ability to eliminate the activated oxygen, lowered the membrane peroxidation level, increased the content of iPAs, lightened the accumulation of ABA both in flag leaves and roots; retarded the falling of photosynthesis ability of flag leaves and activity of roots and accele rated the grain growing rate. As a result the grain weight and yield were increased.