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| Effects of cadmium stress on chloroplast damage and reactive oxygen metabolism of Plagiomnium acutum |
| Received:September 26, 2019 |
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| KeyWord:Plagiomnium acutum;cadmium;chloroplast damage;cadmium subcellular distribution;reactive oxygen metabolism |
| Author Name | Affiliation | | LI Zhao-yang | College of Biology and Environmental Science, Jishou University, Jishou 416000, China
Key Laboratory of Plant Resources Conservation and Utilization(Jishou University), College of Hunan Province, Jishou 416000, China | | XIAO Jun-wen | College of Biology and Environmental Science, Jishou University, Jishou 416000, China | | ZUO Shen-jun | College of Biology and Environmental Science, Jishou University, Jishou 416000, China | | CAO Zi-teng | College of Biology and Environmental Science, Jishou University, Jishou 416000, China | | LI Yuan-xin | College of Biology and Environmental Science, Jishou University, Jishou 416000, China | | TIAN Xiang-rong | College of Biology and Environmental Science, Jishou University, Jishou 416000, China
Key Laboratory of Plant Resources Conservation and Utilization(Jishou University), College of Hunan Province, Jishou 416000, China |
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| Abstract: |
| As pioneer species, mosses are frequently used to indicate atmospheric heavy metal pollution owing to their typical physiological characteristics. However, their mechanism of cadmium(Cd)adaptation is unclear. In this study, submerged culture experiments at different Cd concentrations(0, 1, 5, and 10 mg·L-1)were employed to investigate the impact of Cd stress on chloroplasts and reactive oxygen metabolism in the leaves of Plagiomnium acutum. The results showed:Increasing the Cd concentration increased chloroplast damage, including chloroplast shrinkage and vacuolization. The contents of Cd in different locations in the leaves of P. acutum were distributed in the following order:cell wall > organelle > soluble fraction. The percentage of Cd in the organelles increased as the Cd concentration increased. With an increased Cd concentration, O2-· initially decreased and then increased, but H2O2 continuously increased. Compared with the controls, the O2-· and H2O2 both increased to the maximum values of 7.9% and 13.7%, respectively, when 10 mg·L-1 of Cd was used. Cd stress obviously stimulated ascorbate peroxidase(APX)and glutathione reductase(GR)activities. Compared with the controls, the APX increased 947%, 810%, and 712%, while the GR increased 430%, 765%, and 1125%, respectively, at Cd concentrations of 1, 5, and 10 mg·L-1. There was a dose-effect relationship between the ascorbic acid content and Cd concentration tested, especially regarding reduced ascorbic acid, which increased by 42.7%, 72.7%, and 89.2% compared with the controls, respectively, at Cd concentrations of 1, 5, and 10 mg·L-1. In summary, Cd cause chloroplast damage, lead to denatured and inactivated APX, and abruptly induced the production of reactive oxygen species (ROS). Therefore, the Halliwell-Asada pathway can be the main ROS scavenging mechanism of P. acutum. |
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