长期遮光对冬小麦群体及单叶光合特性的影响(英文)

目的]研究长期弱光对冬小麦(Triticum aestivumL.)群体光合速率(CAP)以及上3叶特别是旗叶光合特性的影响。方法]以耐弱光性不同的冬小麦品种扬麦158和扬麦11为材料,设不遮光(S0)、从拔节至成熟期遮去小麦冠层自然光强的22%(S1)和33%(S2)3个处理,测定小麦CAP、上3叶的光合速率(Pn)、旗叶叶绿素含量以及籽粒产量。结果]扬麦158和扬麦11CAP随遮光强度的增强而显著下降;长期弱光下,旗叶Pn显著下降,倒2叶Pn无明显变化,而倒3叶Pn则显著上升,从而部分地补偿了旗叶Pn的降低。该补偿效应因遮光强度和品种而异:S1处理的补偿效应大于S2处理,扬麦158的补偿效应大于扬麦11。在旗叶光合速率高值持续期内,长期遮光降低了扬麦158和扬麦11总叶绿素、叶绿素a和b的含量,以及叶绿素a/b值。结论]弱光下,旗叶叶绿素a含量以及叶绿素a/b值下降引起其Pn显著降低,从而使得CAP明显降低,最终导致籽粒产量显著下降。该研究可为长江中下游地区的小麦生产提供重要的理论依据。

Effects of Shading on Photosynthetic Properties of Canopy and Single Leaf of Winter Wheat

Objective] The aim was to study on the effects of long-term low radiation on canopy apparent photosynthetic rate(CAP) and photosynthetic properties of top three leaves of winter wheat,especially the flag leaf.Method] Two winter wheat(Triticum aestivum L.) cultivars,Yangmai 158 and Yangmai 11,which differed in low radiation resistance,were used to measure the CAP,photosynthetic rate(Pn) of the top three leaves,chlorophyll content of flag leaf and grain yield.In the test,three treatments were designed from jointing to maturity,as follows:control without shading(S0),S1 and S2 treatments with 22% and 33% sunshine shaded.Result] CAP of Yangmai 158 and Yangmai 11 declined with shading.Under low radiation,Pn of flag leaf declined significantly,while no obvious effects were found on Pn of the 2nd leaf,and Pn of the 3rd leaf increased significantly,which partially compensated the decrease of Pn of the flag leaf.In addition,the compensation effect differed in shading and cultivars:compensation effect in S1 group was higher than that of S2 and effect of Yangmai 158 was higher than that of Yangmai 11.During the period of high Pn,shading decreased the content of total chlorophyll,chlorophyll a,b,and a/b.Conclusion] Under low radiation,the decrease of chlorophyll a and a/b led to substantial declining of Pn,and CAP declined accordingly,finally resulting in drop of grain yield.The research provides important theoretical basis for wheat production in the middle and lower reaches of Yangtze River.