遮阴对南疆冬小麦光合特性和产量的影响

Effect of Shading on the Photosynthetic Characteristics and Yield in Winter Wheat in Southern Xinjiang

【目的】在小麦生长中后期,采用人工模拟核桃、杏、红枣三种果树不同程度遮阴条件下,研究分析不同遮阴处理对小麦光合特性、干物质积累及分配和产量的影响,为新疆南疆果树-小麦间作模式下小麦高产栽培管理提供理论依据。【方法】供试冬小麦品种为新冬20号,遮阴处理设置4个水平,S1:拔节期遮阴10%-抽穗期遮阴25%,S2:拔节期遮阴20%-抽穗期遮阴50%,S3:拔节期遮阴30%-抽穗期遮阴75%,S0:不遮阴。遮阴均从小麦拔节期至成熟期。【结果】小麦扬花期随着遮阴幅度的增大,小麦旗叶光合速率显著降低;灌浆期轻度遮阴Pn与对照无明显差异,但显著高于S2和S3处理;蒸腾速率和气孔导度均随着遮阴幅度的增大而降低,胞间CO 2浓度随着遮阴幅度的增大而增大。随着遮阴幅度的增大总干物质积累量和向籽粒的分配均呈降低趋势,干物质向籽粒的分配率分别降低9.5%、24.2%和27.7%;收获穗数、千粒重、产量和经济系数均随着遮阴幅度的增大而显著降低,而轻度遮阴对穗粒数的影响不明显。随着遮阴幅度的增大,产量和经济系数分别降低22.%、42.9%、67.8%和8.9%、23.8%、27.6%。【结论】随着遮阴幅度的增加,小麦光合速率、蒸腾速率和气孔导度降低,胞间CO 2浓度升高,总干物质积累量和向籽粒的分配比例降低,轻度遮阴收获穗数和千粒重降低,中度和重度遮阴产量三要素均显著降低,导致产量和经济系数显著降低。

【Objective】To study the effects of different shading treatments on photosynthetic characteristics and yield of winter wheat in the hope of providing theoretical basis for high yield cultivation and management of wheat under fruit tree and wheat intercropping model in southern Xinjiang by using artificial shade simulation of three kinds of fruit trees(walnut,apricot and jujube)under the condition of the middle and later periods of the wheat growth in different degree of shade.【Method】The winter wheat variety tested was Xindong 20,and four treatments were set in the shading treatment:S1:shading at the pulling-heading stage was 10%-25%,S2:shading at the pulling-heading stage was 20%-50%,S3:shading at the pulling-heading stage was 30%-75%and S0:not shading at the pulling stage.Shading was from the jointing stage to maturity stage and the effects of shading on photosynthesis,dry matter accumulation,distribution and yield of wheat were studied.【Result】The photosynthetic rate of wheat flag leaf decreased significantly with the increase of shade during blooming period.There was no significant difference between mild shade Pn in grouting period and control period,but it was significantly higher than those of S2 and S3 treatment.Both Tr and Gs decreased with the increase of shading amplitude,and Ci increased with the increase of shading amplitude.With the increase of shading amplitude,the amount of total dry matter accumulation and the distribution to seeds all showed a decreasing trend,the distribution of dry matter to grain decreased by 9.5%,24.2%and 27.7%respectively.The number of ears harvested,1,000-grain weight,yield and economic coefficient all decreased significantly with the increase of shading amplitude,while the effect of light shading on panicle number was not obvious.The yield and economic coefficient decreased by 22%,42.9%,67.8%and 8.9%,23.8%and 27.6%,respectively with the increase of shading amplitude.【Conclusion】With the increase of shading amplitude,Pn,Tr and Gs of wheat were decreased,intracellular CO 2 concentration increased,total dry matter accumulation and distribution ratio to grain decreased,panicle number and 1,000-grain weight decreased,moderate and severe shading yield decreased significantly,resulting in a significant decrease in yield and economic coefficient.