弱光及氮肥互作对冬小麦叶源特性、氮素利用率及产量影响的研究

Light and nitrogen are two important factors of crop growth, and there is a significant interaction effects.There are more than 300,000 hectares of wheat inter-cropped with fruit trees in South of Xinjiang, and the poor light became an important limited factor for wheat production.Inter-cropping Wheat grew poorly and decreased more than 27.7%,the heaviest over 77.3% by long term poor light stress by fruit trees.The applicant of project have a good research basement on wheat inter-cropping with fruit trees ever funded by a project of national science and technology.Three typical winter wheat varieties of Southern Xinjiang are involved in this study, simulating different shading on wheat of three kinds of fruit trees from elongation to maturity stage in field by artificial shading,dealing with different nitrogen fertilizer lever as well. To analyze the relationships between poor light and wheat inherent physiology, external organ composition. To analyze internal relations between low light with senescence and endogenous hormones.To reveal effect mechanism on wheat yield production by poor light.By comparing effect of nitrogen to wheat leaf source character,nitrogen utilization efficiency and yield production in different shading lever, definite effect mechanism on wheat growth and development by interaction of low light and nitrogen fertilizer, and compensation effect of nitrogen fertilizer to poor light stress.Expect to provide a theoretical basis for wheat variety using, shading resistance,high nitrogen use efficiency,variety improvement and high efficient management of nitrogen in wheat inter-cropping with fruit trees in southern Xinjiang.

光照和氮素是作物生长的两个重要因素，存在明显的互作效应。新疆南疆地区500多万亩小麦与果树间作，光照成为限制该区小麦高产的重要因子。受果树长期遮阴等影响，间作小麦生长不良，减产27.7%以上，严重减产达77.3%。本项目在申请人主持的国家科技支撑课题有关果麦间作小麦研究工作基础上，以南疆具有代表性的3个冬小麦品种为研究对象，采用人工遮阴模拟田间3种果树对小麦生长中后期不同程度遮阴（拔节到成熟期）及不同氮素互作条件下，利用生理生化及酶学方法，分析弱光与小麦内在生理及外在器官构成的关系、弱光与衰老特性、内源激素变化的内在联系，揭示弱光对小麦产量形成的影响机制。通过比较不同遮阴程度时，施氮对小麦叶源特性、氮素利用及产量构成的影响，明确弱光及氮素互作对小麦生长发育的影响机理和氮素调控对光胁迫的补偿效应。以期为南疆果麦间作模式下小麦品种选用、耐阴、高效氮素利用率品种遗传改良和氮高效管理提供理论依据。

新疆南疆70%左右的小麦与果树间作，形成了特有的果树（核桃、杏、红枣等）与小麦复合生产模式。本项目执行期为2016年1月至2019年12月，采用人工遮光与氮肥处理，研究了光氮互作对南疆冬小麦叶源特性、产量及氮素利用率的影响，揭示了果麦间作复合系统中长期弱光影响小麦生长发育及产量形成的内在生理机制，明确了氮素调控对光胁迫的补偿效应。完成了研究计划目标和任务，达到了预期的研究结果。.1、随着遮阴强度与施氮量的增加，扬花至成熟期持续时间延长。在轻度遮阴和不遮阴下，成穗数随着施氮量的增加先增后降；在中度和重度遮阴下，随着施氮量的增加而降低。.2、在轻度遮阴下，小麦光合面积、色素含量增加，光合机构PSII的实际光化学效率和所占的比例升高，适量施氮（拔节期追施纯氮9.2kg/亩）能改善轻度遮阴下小麦扬花期光合性能。在中度和重度遮阴下，小麦光合面积、色素含量和光合速率显著降低，且施氮的调控效应降低。.3、在轻度遮阴下，适量施氮能促进茎叶中干物质向籽粒转移；在中度和重度遮阴下，施氮（拔节期追施纯氮6.9kg/亩以上）使茎叶中积累量增加，总干物质积累量及向籽粒中分配降低。.4、在轻度遮阴下，适量施氮能促进植株氮素积累及向籽粒分配；在中度和重度遮阴下，施氮不利于氮素积累及向籽粒分配，氮素利用率降低。.5、在轻度遮阴下，小麦旗叶SOD、POD、CAT活性增加，IAA和GA3含量提高，NR活性降低，适量施氮能增强叶片的生理活性。在中度和重度遮阴下，施氮对叶片生理活性的调控效应降低。.6、在轻度遮阴下，适量施氮穗粒数和千粒重与对照无明显差异，收获穗数及产量低于对照；在中度和重度遮阴下，施氮对产量形成的调控效应降低。.7、在轻度遮阴和不遮阴下，新冬40适量施氮产量高于其它品种，在中度和重度遮阴下，施氮对产量的调控效应降低，3品种产量显著下降。.8、在核心期刊发表论文2篇，已接收2篇；申请发明专利1项；培养硕士研究生1名。