Yang Hongkun, Zhao Jiarong, Ma Hongliang, Shi Zhiqiang, Huang Xiulan, Fan Gaoqiong
State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Ministry of Science and Technology, Chengdu 611130, Sichuan, PR China.
Biotechnology and Nuclear Technology Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, Sichuan 610061, PR China.
Int J Biol Macromol. 2023 May 1;236:123972. doi: 10.1016/j.ijbiomac.2023.123972. Epub 2023 Mar 9.
Heavy haze-induced decreases in solar radiation represent an important factor that affects the structural properties of starch macromolecules. However, the relationship between the photosynthetic light response of flag leaves and the structural properties of starch remains unclear. In this study, we investigated the impact of light deprivation (60 %) during the vegetative-growth or grain-filling stage on the leaf light response, starch structure, and biscuit-baking quality of four wheat cultivars with contrasting shade tolerance. Shading decreased the apparent quantum yield and maximum net photosynthetic rate of flag leaves, resulting in a lower grain-filling rate and starch content and higher protein content. Shading decreased the starch, amylose, and small starch granule amount and swelling power but increased the larger starch granule amount. Under shade stress, the lower amylose content decreased the resistant starch content while increasing the starch digestibility and estimated glycemic index. Shading during the vegetative-growth stage increased starch crystallinity, 1045/1022 cm ratio, starch viscosity, and the biscuit spread ratio, while shading during the grain-filling stage decreased these values. Overall, this study indicated that low light affects the starch structure and biscuit spread ratio by regulating the photosynthetic light response of flag leaves.
严重雾霾导致的太阳辐射减少是影响淀粉大分子结构特性的一个重要因素。然而，旗叶光合光响应与淀粉结构特性之间的关系仍不清楚。在本研究中，我们调查了在营养生长或灌浆期遮光60%对四个耐荫性不同的小麦品种叶片光响应、淀粉结构和饼干烘焙品质的影响。遮光降低了旗叶的表观量子产率和最大净光合速率，导致灌浆速率和淀粉含量降低，蛋白质含量升高。遮光减少了淀粉、直链淀粉和小淀粉颗粒的数量以及膨胀力，但增加了大淀粉颗粒的数量。在遮荫胁迫下，较低的直链淀粉含量降低了抗性淀粉含量，同时增加了淀粉消化率和估计血糖指数。营养生长阶段遮光增加了淀粉结晶度、1045/1022 cm比值、淀粉粘度和饼干扩展率，而灌浆期遮光则降低了这些值。总体而言，本研究表明弱光通过调节旗叶光合光响应来影响淀粉结构和饼干扩展率。
