花后弱光对软质小麦籽粒产量与淀粉品质的影响

Effect of Weak Light after Anthesis on Grain Yield and Starch Quality in Soft Wheat

为探明花后弱光胁迫对软质小麦籽粒产量、淀粉粒度分布及黏度参数的影响,以软质小麦品种荃麦725和扬麦15为材料,在小麦开花后设置3个弱光处理即S1(遮光10%)、S2(遮光20%)、S3(遮光30%)处理,以自然光照条件为对照,分析花后不同程度弱光条件下软质小麦籽粒产量、淀粉粒度分布与黏度参数的差异。结果表明,与对照相比,花后弱光降低了小麦粒重、穗粒数和产量,提高了籽粒蛋白质含量,但使籽粒淀粉含量、籽粒蛋白质和淀粉积累量显著减少。花后弱光降低了软质小麦B型淀粉粒(粒径≤10μm)体积、表面积百分比,增加了A型淀粉粒(粒径>10μm)体积、表面积百分比,对A、B型淀粉粒数目百分比无显著影响。在B型淀粉粒中,弱光对粒径0.1~2.8μm的淀粉粒体积百分比的影响较粒径2.8~10μm的淀粉粒大。在A型淀粉粒中,弱光对粒径>22μm的淀粉粒体积百分比的影响大于粒径10~22μm的淀粉粒。弱光导致小麦籽粒淀粉峰值黏度、低谷黏度、最终黏度、稀懈值、回升值等参数显著下降。花后弱光虽然可增加软质小麦籽粒蛋白质含量,但显著降低籽粒淀粉含量以及蛋白质和淀粉积累量,不利于粒重与产量形成;弱光对B型淀粉粒的影响大于A型淀粉粒,会降低B型淀粉粒体积和表面积占比,但可增加A型淀粉粒体积和表面积占比,降低淀粉峰值黏度等参数。

To investigate the effects of post flowering weak light stress on the grain yield,starch particle size distribution,and viscosity parameters of soft wheat,three weak light treatments,namely S1(10%shading),S2(20%shading),and S3(30%shading),were set up after wheat flowering using soft wheat varieties Quanmai 725 and Yangmai 15 as materials.Natural light conditions were used as control to analyze the grain yield and changes in starch particle size distribution and viscosity parameters of soft wheat under different degrees of weak light conditions after flowering.The results showed that compared with the control,weak light after flowering reduced wheat grain weight,spike grain number and yield,increased grain protein content,but significantly reduced grain starch content,grain protein and starch accumulation.After flowering,weak light reduced the B-type starch granules of soft wheat(particle size≤10μm)in volume and surface area percentage,increased A-type starch granules(particle size>10μm)in volume and surface area percentage,but had no significant effect on the number percentage of A and B type starch granules.In B-type starch granules,weak light affected volume percentage more on the particle size from 0.1 to 2.8μm than that of the particle size of 2.8-10μm.In A-type starch granules,weak light affected volume percentage more on the particle size over 22μm than that of the particle size of 10-22μm.Weak light led to a significant decrease in parameters such as peak viscosity,trough viscosity,final viscosity,breakdown,and setback of wheat starch.Although weak light after flowering can increase the protein content of soft wheat grains,it significantly reduces the starch content and protein and starch accumulation,which is not conducive to the formation of grain weight and yield.The effect of weak light on B-type starch granules is greater than that on A-type starch granules,which will reduce the volume and surface area proportion of B-type starch granules,but can increase the volume and surface area proportion of A-type starch granules,and reduce parameters such as starch peak viscosity.