Nitrogen Supply Mitigates Heat Stress on Photosynthesis of Maize (Zea mays L.) During Early Grain Filling by Improving Nitrogen Assimilation

文献类型： 外文期刊

第一作者： Guo, Dong

作者： Guo, Dong;Wang, Rui;Ding, Zaisong;Wang, Xinbing;Zhao, Ming;Zhou, Baoyuan;Guo, Dong;Chen, Chuanyong;Yin, Baozhong

作者机构：

关键词： enzymatic activity; heat stress; nitrogen assimilation; nitrogen supply; photosynthesis

期刊名称：JOURNAL OF AGRONOMY AND CROP SCIENCE （ 影响因子：3.7； 五年影响因子：4.0 ）

ISSN： 0931-2250

年卷期： 2024 年 210 卷 5 期

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收录情况： SCI

摘要： High temperature during early grain-filling stage is one of the serious abiotic stresses limiting maize yield in the North China Plain. Nitrogen (N) fertiliser has an important role in promoting crop growth, especially under abiotic stresses. However, its contribution to alleviating heat stress (HS) inhibition on maize photosynthesis during early grain-filling stage is still unclear. Experiments with three N rates (LN, low nitrogen; MN, medium nitrogen; HN, high nitrogen) and two temperature (HS, heat stress; CK, ambient temperature as control) regimes were conducted to examine the effects of increasing N supply on photosynthesis, N assimilation, antioxidant system, and hormones homeostasis of maize during early grain-filling stage using two maize hybrids Xianyu335 (XY335, heat-sensitive) and Zhengdan (ZD958, heat-tolerant). HS negatively affected photosynthesis of both two hybrids, exhibited lower net photosynthetic rate, chlorophyll content and activities of Rubisco and phosphoenolpyruvate carboxylase (PEPC) compared with CK, and then decreased dry matter accumulation of maize, with a lesser extent for ZD958 than XY335. However, increasing N supply alleviated the adverse effects of HS on maize photosynthesis due to improved N assimilation capacity. Under HS condition, greater N content and higher activities of glutamine synthetase and glutamate synthase in maize ear leaf were found in treatment of HN compared with LN and MN. HN with higher N assimilation capacity directly increased the net photosynthetic rate due to improved chlorophyll content, activities of Rubisco and PEPC and antioxidant capacity. HS-induced abscisic acid (ABA) accumulation was also repressed by HN, and then enhanced the stomatal conductance and transpiration rate to maintain higher photosynthetic capacity compared with LN and MN. Moreover, the positive effects of increasing N supply on maize photosynthesis under HS condition exhibited a larger extent for XY335 than ZD958. As a result of improved photosynthesis and N assimilation capacity by adequate N supply, maize accumulated more biomass under HS, especially for heat-sensitive hybrid.

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