花前遮阴对小麦光合特性和产量形成的影响
关键词：小麦；遮阴；光合特性；产量
Effects of Pre-anthesis shading on Photosynthetic characteristics and grain yield in wheat
Abstract：Due to climate change and air pollution，the solar radiation in the middle and lower reaches of the Yangtze River continues to decline，and weak radiation has became one of the most important factors that restrict wheat production in this region. The aim of this study is to elucidate the response and adaptation mechanism of wheat to weak radiation stress in order to provide theoretical guidelines for high yield maintaining under weak radiation conditions. Field experiment was conducted using two wheat cultivars, Yangmai 158 and yangfumai 4, to study the effect of moderate shading (70% radiation) and severe shading (50% radiation) from jointing to anthesis on photosynthetic characteristics and grain yield of wheat. The results showed that under shading conditions, both cultivars exhibited a yield decrease, and the decrements were dependant on stress severity and genotypic responses. Relatively lower yield decrease degree was observed when weak radiation was occurred at moderate level for Yangfumai 4. Besides, shading from jointing to anthesis mainly reduced grains per spike. Furthermore, shading from joint to anthesis significantly lowered net photosynthetic rate and specific leaf weight, but increased leaf area. Therefore, selecting tolerant varieties to weak radiation and adopting reasonable cultivation measures in different growth stage will beneficial to improve photosynthetic characteristics and reduce yield loss under weak radiation conditions.
Key words: Wheat; Shading; Photosynthetic characteristics; Yield
目 录
摘要2
关键词2
Abstract2
Key words3
引言3
1材料与方法3
1.1实验设计 3
1.2测定项目和方法 3
1.2.1净光合速率3
1.2.2叶面积和比叶重3
1.2.3叶绿素含量（SPAD）4
1.2.4花后干物质转运4
1.2.5生长速率4
1.2.6产量和产量构成4
1.3数据分析4
2结果与分析4
2.1产量和产量构成的因素4
2.2生长速率5
2.3花后干物质转运6
2.4叶面积和比叶重6
2.5叶绿素含量（SPAD）和净光合速率7
3讨论9
3.1遮阴对小麦产量和生长速率的影响9
3.2遮阴对小麦光合特性的影响9
4结论10
致谢10
参考文献10
花前遮阴对小麦光合特性和产量形成的影响
我国的小麦产量占全世界总产量的优尔分之一，针对小麦产量的相关研究对于我国的粮食安全现状有着极为深刻的意义。黄淮海麦区和长江中下游麦区（30～42°N）是时我国重要的小麦产区[1]，超过70％的小麦面积和产量分布在这里。但随气候变化和现代种植模式的改变，该区域的太阳辐射持续下降，弱光现象已然成为了小麦种植的主要逆境之一[2]。
太阳辐射是光合作用的能源，小麦正是通过一系列能量转化过程，以干物质的形式将太阳能转变成体内的化学能储存起来[5]，因此光照强度的变化对小麦的生长和产量的形成有直接的影响。而小麦的产量则是由单位面积穗数、每穗粒数和每粒粒重构成[2-4]，在其形成的过程中，光合产物的生成、转运及向库里的分配能力是制约产量的重要因素[6]。另一方面，小麦光合产物的多少取决于光合面积、光合强度与光合时间三因素，光合产物的分配最终决定了小麦的产量[7]。因此没我们在衡量小麦的光合能力的时候就主要包含了叶片的光合速率，叶面积和比叶重以及叶绿素含量三个指标[8]。另外，孕穗期是小麦小穗分化发育的重要时期，孕穗期小麦生长情况的好坏直接影响了小麦产量的形成。