ABSTRACT The wide application of zinc oxide (ZnO) nanoparticles inevitably facilities their release into the terrestrial and agricultural ecosystems, severely affecting crop production. The effects of nano-ZnO (100 mg L−1) on stomatal morphology, gas exchange and key carbon metabolism enzyme activities were investigated in drought-stressed and well-watered maize. Drought stress limited the plant growth, caused stomatal closure, decreased the net photosynthetic rate, while increased the osmolyte concentrations. In drought-stressed maize, the application of nano-ZnO (100 mg L−1) alleviated photosynthetic pigment degradation and benefited the stomatal movement, maintained a higher net photosynthetic rate, and enhanced water use efficiency, promoting the drought tolerance in maize. In addition, the nano-ZnO increased the activities of UDP-glucose pyrophosphorylase, phosphoglucoisomerase and cytoplasmic invertase by 17.8%, 391.5% and 126%, respectively, which enhanced the starch and sucrose biosynthesis and glycolysis metabolism in leaves under drought stress. Manipulation of primary carbohydrate metabolism through nano-ZnO induced regulation of the key enzymes activity benefited the drought tolerance in maize. The nano-ZnO application (100 mg L−1) alleviates the negative effect of drought stress via improving photosynthetic carbon assimilation of maize.

中文翻译：

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纳米氧化锌通过调节玉米的植物水分利用和碳水化合物代谢缓解干旱胁迫

摘要氧化锌（ZnO）纳米粒子的广泛应用不可避免地促进了它们释放到陆地和农业生态系统中，严重影响了作物生产。在干旱胁迫和水分充足的玉米中研究了纳米氧化锌 (100 mg L-1) 对气孔形态、气体交换和关键碳代谢酶活性的影响。干旱胁迫限制了植物的生长，导致气孔关闭，降低了净光合速率，同时增加了渗透物浓度。在干旱胁迫的玉米中，纳米ZnO（100 mg L-1）的应用减轻了光合色素降解，有利于气孔运动，保持较高的净光合速率，提高水分利用效率，促进玉米的耐旱性。此外，纳米氧化锌使UDP-葡萄糖焦磷酸化酶、磷酸葡萄糖异构酶和细胞质转化酶的活性分别提高了17.8%、391.5%和126%，从而增强了干旱胁迫下叶片的淀粉和蔗糖生物合成和糖酵解代谢。通过纳米氧化锌诱导的关键酶活性调节来调控初级碳水化合物代谢有利于玉米的耐旱性。纳米 ZnO 应用（100 mg L-1）通过改善玉米的光合碳同化来减轻干旱胁迫的负面影响。通过纳米氧化锌诱导的关键酶活性调节来调控初级碳水化合物代谢有利于玉米的耐旱性。纳米 ZnO 应用（100 mg L-1）通过改善玉米的光合碳同化来减轻干旱胁迫的负面影响。通过纳米氧化锌诱导的关键酶活性调节来调控初级碳水化合物代谢有利于玉米的耐旱性。纳米 ZnO 应用（100 mg L-1）通过改善玉米的光合碳同化来减轻干旱胁迫的负面影响。