遮阴时期对不同小麦品种淀粉组成结构及淀粉品质的影响

Effects of Shading Stage on the Starch Component and Starch Quality of Different Wheat Cultivar

为研究花前和花后弱光对不同小麦品种淀粉特性的影响,2020—2021年在西昌农科院基地设计二因素裂区试验,主区因素为品种,分别为蜀麦482、川麦39、绵麦51和昌麦34,副区因素为遮阴时期,分别为拔节-开花期(S1)和拔节-成熟期(S2),自然光强为对照(CK)。结果表明,遮阴显著抑制籽粒淀粉积累,拔节-开花期、拔节-成熟期遮阴使淀粉含量分别下降2.96和5.34个百分点,直/支比无显著变化。拔节-成熟期遮阴,A型淀粉粒(>10μm)数目、体积和表面积占比分别较CK提高0.10、4.49和5.01个百分点,α-淀粉酶活性提高36.6%,面粉降落值、糊化黏度和膨胀势降低,淀粉品质变劣;拔节-开花期遮阴降低绵麦51籽粒α-淀粉酶活性,较CK减小28.6%,淀粉糊化黏度、膨胀势和降落值显著增加,淀粉品质改善。绵麦51籽粒α-淀粉酶活性较高,是其他品种的1.55~2.61倍,淀粉峰值黏度、降落值和膨胀势分别较其他品种低948.1~1597.8 Pa·s、108~211 s、2.95~3.88 g·g^(-1),且对光照变化更敏感。相关性分析表明,降落值与峰值黏度等糊化黏度(RVA)参数、膨胀势呈极显著正相关,α-淀粉酶活性与之呈极显著负相关。研究认为,灌浆期弱光通过降低淀粉含量和增加α-淀粉酶活性劣化小麦淀粉品质,低降落值品种绵麦51环境稳定性差,在多阴雨寡照区,建议选择高降落值品种以减小灌浆期弱光产生的不利影响。本研究结果有助于深化小麦淀粉品质研究和指导弱光照区域小麦生产。

To study effects of low light before and after anthesis on the starch properties of different wheat cultivars,the experiment was carried out in the Xichang Academy of Agricultural Sciences base from 2020 to 2021,and was laid out in a two-factor split-plot design,with Shumai482,Chuanmai39,Mianmai51 and Changmai34 as the main plots and the sub-plots as shading stage,which were jointing-flowering stage(S1)and jointing-maturity stage(S2),and normal light was used as control(CK).The results showed that shading during different stage significantly inhibited the accumulation of starch in wheat grains.Compared with CK,the starch content at S1 and S2 decreased by 2.96%and 5.34%,respectively,but there was no significant change in amylose/amylopectin ratio.The number,volume and surface area distribution of A-type starch granules(<10μm)under S2 treatment were 0.10%,4.49%,and 5.01%higher than CK,respectively,but starch quality became worse,because theα-amylase activity increased by 36.6%,and the falling number,starch past viscosity swelling power decreased.Under S1 treatment,starch quality improved because theα-amylase activity of Mianmai51 was 28.6%lower than CK,while the pasting viscosity,swelling power,falling number increased.Mianmai51 was more sensitive to light changes,and itsα-amylase activity was 1.55~2.61 times those of other cultivars,and the peak viscosity,the falling number and swelling power were 948.1~1597.8 cp,108~211 s,2.95~3.88 g·g^(-1) lower than those of other cultivars.Correlation analysis showed that the falling number had a very significant positive correlation with swelling power and some RVA parameters such as the peak viscosity,butα-amylase activity was negatively correlated with it.The study showed that low light at grain filling stage deteriorated wheat processing quality by reducing starch content and increasingα-amylase activity,lower falling number cultivar Mianmai51 had poor environmental stability.It was recommended to choose higher falling number cultivar to reduce the adverse effect of low light during grain filling stage on starch quality.This study will help deepen the wheat starch quality research and guide wheat production in low-light areas.