Zhang Zhe, Ma Rongrong, Tao Yihui, Ma Haizhen, Jiang Xiaoyu, Wang Ziling, Yang Yingli
College of Life Science, Northwest Normal University, Lanzhou 730070, PR China.
College of Life Science, Northwest Normal University, Lanzhou 730070, PR China.
Ecotoxicol Environ Saf. 2025 Sep 1;302:118661. doi: 10.1016/j.ecoenv.2025.118661. Epub 2025 Jul 11.
Heavy metals including iron (Fe) and copper (Cu) pollution in soil is threatening the ecological environment and crop yield. In this experiment, photosynthetic characteristics, stomatal microstructure and proline (Pro) metabolism in wheat variety 'Xihan 3' seedlings were assessed to explore the mechanism of phytotoxicity induced by various combinations of zinc (Zn), Fe and Cu. Compared with the control, Zn + Fe, Zn + Cu, Fe + Cu and Zn + Fe + Cu treatments obviously lowered the shoot and root lengths, reduced leaf area and root number, along with the increases of malondialdehyde, hydrogen peroxide and superoxide anion radicals levels and relative conductivity in wheat leaves. The net photosynthetic rate also lessened with the decreases of chlorophyll (Chl) level, Chl fluorescence parameters, stomatal conductance and stomatal length and width under these combined treatments. Additionally, different combinations of Zn, Fe and Cu increased the amount of osmotic regulators including Pro in wheat roots, up-regulated Δ1-pyrroline-5-carboxylic acid synthetase (P5CS), glutamate kinase, Δ1-pyrroline-5-carboxylate reductase (P5CR) and ornithine aminotransferase (OAT) activities and TaP5CS, TaP5CR and TaOAT expression, but down-regulated Pro dehydrogenase (ProDH) activity and TaProDH expression. Taken together, different combined treatments of Zn, Fe and Cu severely restricted root and leaf development through enhancing oxidative damage and weakening photosynthetic efficiency in wheat leaves, and the combined treatment-caused Pro accumulation in wheat roots could achieved through both glutamate and ornithine synthesis pathway and attenuated Pro degradation.
包括铁（Fe）和铜（Cu）在内的重金属对土壤的污染正威胁着生态环境和作物产量。在本实验中，对小麦品种‘西旱3号’幼苗的光合特性、气孔微观结构和脯氨酸（Pro）代谢进行了评估，以探究锌（Zn）、铁和铜的不同组合所诱导的植物毒性机制。与对照相比，锌 + 铁、锌 + 铜、铁 + 铜和锌 + 铁 + 铜处理显著降低了地上部和根部长度，减少了叶面积和根数，同时小麦叶片中的丙二醛、过氧化氢和超氧阴离子自由基水平以及相对电导率均有所增加。在这些组合处理下，净光合速率也随着叶绿素（Chl）水平、Chl荧光参数、气孔导度以及气孔长度和宽度的降低而减小。此外，锌、铁和铜的不同组合增加了小麦根中包括Pro在内的渗透调节物质的含量，上调了Δ1-吡咯啉-5-羧酸合成酶（P5CS）、谷氨酸激酶、Δ1-吡咯啉-5-羧酸还原酶（P5CR）和鸟氨酸转氨酶（OAT）的活性以及TaP5CS、TaP5CR和TaOAT的表达，但下调了脯氨酸脱氢酶（ProDH）的活性和TaProDH的表达。综上所述，锌、铁和铜的不同组合处理通过增强氧化损伤和削弱小麦叶片的光合效率，严重限制了根和叶的发育，并且组合处理导致的小麦根中Pro积累可通过谷氨酸和鸟氨酸合成途径实现，并减弱Pro的降解。
