文章摘要
李朝阳,肖钧文,左深君,曹子藤,李垣鑫,田向荣.Cd对湿地匍灯藓叶绿体损伤与活性氧的影响[J].农业环境科学学报,2020,39(3):504-510.
Cd对湿地匍灯藓叶绿体损伤与活性氧的影响
Effects of cadmium stress on chloroplast damage and reactive oxygen metabolism of Plagiomnium acutum
投稿时间:2019-09-26  
DOI:10.11654/jaes.2019-1067
中文关键词: 湿地匍灯藓  镉(Cd)  叶绿体损伤  Cd亚细胞分布  活性氧代谢
英文关键词: Plagiomnium acutum  cadmium  chloroplast damage  cadmium subcellular distribution  reactive oxygen metabolism
基金项目:国家自然科学基金项目(31660119)
作者单位
李朝阳 湖南吉首大学生物资源与环境科学学院, 湖南 吉首 416000
植物资源保护与利用湖南省高校重点实验室, 湖南 吉首 416000 
肖钧文 湖南吉首大学生物资源与环境科学学院, 湖南 吉首 416000 
左深君 湖南吉首大学生物资源与环境科学学院, 湖南 吉首 416000 
曹子藤 湖南吉首大学生物资源与环境科学学院, 湖南 吉首 416000 
李垣鑫 湖南吉首大学生物资源与环境科学学院, 湖南 吉首 416000 
田向荣 湖南吉首大学生物资源与环境科学学院, 湖南 吉首 416000
植物资源保护与利用湖南省高校重点实验室, 湖南 吉首 416000 
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中文摘要:
      为探讨不同镉(Cd)浓度胁迫对湿地匍灯藓(Plagiomnium acutum)叶绿体、Cd的亚细胞分布及活性氧代谢的影响,设置了4个Cd浓度梯度(0、1、5、10 mg·L-1),采用浸没培养方法对湿地匍灯藓进行处理。结果表明:随Cd胁迫浓度增加,细胞损伤加大,叶绿体严重皱缩成球状,同时细胞空泡化程度也逐渐加重。Cd在亚细胞组分中的分布为:细胞壁 > 细胞器 > 可溶部分。随Cd浓度增加,细胞器中Cd累积量增加;随Cd胁迫浓度的增加,湿地匍灯藓体内超氧阴离子自由基(O2-·)的产生速率先降后升,过氧化氢(H2O2)的含量则持续上升,均在10 mg·L-1时达到最大值,与对照相比,二者分别增加了7.9%和13.7%;与之对应,抗坏血酸过氧化物酶(APX)活性和谷胱甘肽还原酶(GR)活性均显著增加,与对照相比,两种酶活性分别增加了947%和430%、810%和765%、712%和1125%;藓体内抗坏血酸含量与Cd存在剂量效应关系,尤其是还原型抗坏血酸(ASA),与对照相比分别增加了42.7%、72.7%和89.2%。综上所述,进入藓体内的Cd可能通过攻击叶绿体,使APX变性失活,诱导活性氧产生;而抗坏血酸-谷胱甘肽途径可能是湿地匍灯藓体内主要的活性氧清除机制。
英文摘要:
      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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