Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka, Saudi Arabia.
Department of Botany and Microbiology, Faculty of Science, Cairo University, Giza, 12613, Egypt.
Plant Physiol Biochem. 2021 Sep;166:235-245. doi: 10.1016/j.plaphy.2021.05.036. Epub 2021 Jun 6.
Nano-sized arsenic oxide nanoparticles (AsO-NP) limit crop growth and productivity. AsO-NP represent a strong environmental hazard. The predicted rise in future atmospheric CO could boost plant growth both under optimal and heavy metal stress conditions. So far, the phytotoxicity of AsO-NP and their interaction with eCO were not investigated at physiological and metabolic levels in crop species groups such as C3 and C4. We investigated how eCO level (620 ppm) alleviated soil AsO-NP toxicity induced growth and mitigated oxidative damages through analysing photosynthetic parameters, primary (sugars and amino acids) and secondary (phenolics, flavonoids and anthocyanins) metabolism in C3 (barley) and C4 (maize) plants. Compared to maize, barley accumulated higher AsO-NP level, which inhibited growth and induced oxidative damage particularly in barley (increased HO and lipid peroxidation). Interestingly, eCO differently mitigated AsO-NP toxicity on photosynthesis, which consequently improved sugar metabolism. Moreover, high carbon availability in eCO treated plants directed to produce osmo-protectant (soluble sugars and proline) and antioxidants (anthocyanins and tocopherols). In the line with increased proline and anthocyanins, their metabolism was also improved. Notable differences occurred between the two plant species. The ornithine pathway was preferred in maize while in barley proline accumulation was mainly through glutamate pathway. Moreover, under AsO-NP stress, barley preferentially accumulated anthocyanins while maize accumulated total phenolics and flavonoids. This work contributes to improving our understanding of the differences in growth, physiological and biochemical responses of major crops of two functional photosynthetic groups (C3 and C4 plants) under ambient and elevated CO grown under AsO-NP stress.
纳米级三氧化二砷纳米颗粒（AsO-NP）限制了作物的生长和生产力。AsO-NP 代表了一种强烈的环境危害。预计未来大气 CO 的增加将在最佳和重金属胁迫条件下促进植物生长。到目前为止，还没有在生理和代谢水平上研究过 AsO-NP 的植物毒性及其与 eCO 的相互作用，特别是在 C3 和 C4 等作物群体中。我们研究了在 620 ppm 的 eCO 水平下，如何通过分析光合作用参数、初级代谢产物（糖和氨基酸）和次生代谢产物（酚类、类黄酮和花青素）来缓解土壤 AsO-NP 毒性诱导的生长和减轻氧化损伤在 C3（大麦）和 C4（玉米）植物中。与玉米相比，大麦积累了更高水平的 AsO-NP，这抑制了生长并在大麦中诱导了氧化损伤（增加了 HO 和脂质过氧化）。有趣的是，eCO 以不同的方式缓解了 AsO-NP 对光合作用的毒性，从而改善了糖代谢。此外，eCO 处理植物中高碳可用性促使产生渗透保护剂（可溶性糖和脯氨酸）和抗氧化剂（花青素和生育酚）。与脯氨酸和花青素的增加相一致，它们的代谢也得到了改善。两种植物之间存在显著差异。玉米中优先使用鸟氨酸途径，而在大麦中脯氨酸的积累主要通过谷氨酸途径。此外，在 AsO-NP 胁迫下，大麦优先积累花青素，而玉米则积累总酚类和类黄酮。这项工作有助于提高我们对两种功能光合作用群体（C3 和 C4 植物）主要作物在大气和升高 CO 下生长时，在生长、生理和生化反应方面的差异的理解，同时还受到 AsO-NP 胁迫的影响。
