Chen Xu-Feng, Chen Huan-Huan, Huang Wei-Lin, Huang Wei-Tao, Huang Zeng-Rong, Yang Lin-Tong, Ye Xin, Chen Li-Song
College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Antioxidants (Basel). 2024 Feb 22;13(3):268. doi: 10.3390/antiox13030268.
Citrus is mainly cultivated in acid soil with low boron (B) and high copper (Cu). In this study, seedlings were submitted to 0.5 (control) or 350 μM Cu (Cu excess or Cu exposure) and 2.5, 10, or 25 μM B for 24 weeks. Thereafter, HO production rate (HPR), superoxide production rate (SAPR), malondialdehyde, methylglyoxal, and reactive oxygen species (ROS) and methylglyoxal detoxification systems were measured in leaves and roots in order to test the hypothesis that B addition mitigated Cu excess-induced oxidative damage in leaves and roots by reducing the Cu excess-induced formation and accumulation of ROS and MG and by counteracting the impairments of Cu excess on ROS and methylglyoxal detoxification systems. Cu and B treatments displayed an interactive influence on ROS and methylglyoxal formation and their detoxification systems. Cu excess increased the HPR, SAPR, methylglyoxal level, and malondialdehyde level by 10.9% (54.3%), 38.9% (31.4%), 50.3% (24.9%), and 312.4% (585.4%), respectively, in leaves (roots) of 2.5 μM B-treated seedlings, while it only increased the malondialdehyde level by 48.5% (97.8%) in leaves (roots) of 25 μM B-treated seedlings. Additionally, B addition counteracted the impairments of Cu excess on antioxidant enzymes, ascorbate-glutathione cycle, sulfur metabolism-related enzymes, sulfur-containing compounds, and methylglyoxal detoxification system, thereby protecting the leaves and roots of Cu-exposed seedlings against oxidative damage via the coordinated actions of ROS and methylglyoxal removal systems. Our findings corroborated the hypothesis that B addition alleviated Cu excess-induced oxidative damage in leaves and roots by decreasing the Cu excess-induced formation and accumulation of ROS and MG and by lessening the impairments of Cu excess on their detoxification systems. Further analysis indicated that the pathways involved in the B-induced amelioration of oxidative stress caused by Cu excess differed between leaves and roots.
柑橘主要种植在硼（B）含量低且铜（Cu）含量高的酸性土壤中。在本研究中，将幼苗分别置于0.5（对照）或350 μM铜（铜过量或铜暴露）以及2.5、10或25 μM硼的环境中处理24周。此后，测定叶片和根系中的过氧化氢产生速率（HPR）、超氧化物产生速率（SAPR）、丙二醛、甲基乙二醛、活性氧（ROS）以及甲基乙二醛解毒系统，以验证以下假设：添加硼可通过减少铜过量诱导的ROS和甲基乙二醛的形成与积累，并抵消铜过量对ROS和甲基乙二醛解毒系统的损害，从而减轻铜过量对叶片和根系造成的氧化损伤。铜和硼处理对ROS和甲基乙二醛的形成及其解毒系统具有交互影响。在2.5 μM硼处理的幼苗叶片（根系）中，铜过量分别使HPR、SAPR、甲基乙二醛水平和丙二醛水平提高了10.9%（54.3%）、38.9%（31.4%）、50.3%（24.9%）和312.4%（585.4%），而在25 μM硼处理的幼苗叶片（根系）中，铜过量仅使丙二醛水平提高了48.5%（97.8%）。此外，添加硼抵消了铜过量对抗氧化酶、抗坏血酸-谷胱甘肽循环、硫代谢相关酶、含硫化合物以及甲基乙二醛解毒系统的损害，从而通过ROS和甲基乙二醛清除系统的协同作用保护暴露于铜环境中的幼苗叶片和根系免受氧化损伤。我们的研究结果证实了以下假设：添加硼可通过减少铜过量诱导的ROS和甲基乙二醛的形成与积累，并减轻铜过量对其解毒系统的损害，从而缓解铜过量对叶片和根系造成的氧化损伤。进一步分析表明，叶片和根系中硼诱导缓解铜过量引起的氧化应激所涉及的途径有所不同。
