小麦根系活力变化与叶片衰老的研究

对小麦根系活力、叶片叶绿素含量和光合速率变化的田问实验结果表明，根系活力的衰退早且快于叶片叶绿素含量和光合速率的衰退；根系活力和叶片光合速率呈正相关关系(r=0．8006)．拔节期追施氮肥，改善根际营养条件后，叶片的光合速率、根系活力明显提高，叶片中ABA含量降低，ZRs升高,SOD活性增加，MDA的高峰期比对照推迟8～10d，说明根系活力变化与地上部叶片的衰老密切相关，改善根际营养，提高生育前期的根系活力有助于延缓地上部分的衰老．

Relationship between wheat root activity and leaf senescence

A field trial on the wheat root activity, chlorophyll content and photosynthetic rate showed that the decline of root activity was earlier and faster than that of flag leaf chlorophyll content and photosynthetic rate, and there was a positive correlation between root activity and leaf photosynthetic rate (r = 0.8006). Topdressing nitrogen fertilizer at elongation stage could obviously improve root activity and photosynthetic rate, decrease leaf ABA content, increase ZRs content and SOD activity, and delay the peak value of MDA for 8-10 days, which suggested that the variation of root activity was closely related to the senescence of flag leaf. Improving root nutrition and root activity at earlier growth stages could delay the senescence of wheatleaf.