铀胁迫对不同苔藓生长及抗氧化系统的影响

李俊柯 1; 杜家豪 1; 邓章轩 1; 罗中旭 1; 赖金龙 1; 2; 罗学刚 1; 2

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李俊柯 1，杜家豪 1，邓章轩 1，罗中旭 1，赖金龙 1,2，罗学刚 1,2.铀胁迫对不同苔藓生长及抗氧化系统的影响[J].广东农业科学,2020,47(8):65-73

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Effects of Uranium Stress on Growth and Antioxidant System of Different Bryophytes

DOI：10.16768/j.issn.1004-874X.2020.08.009

中文关键词: 铀（U）抗氧化酶活性氧系统苔藓耐受性

英文关键词: uranium（U） antioxidant enzyme active oxygen system bryophyte tolerance

基金项目:国民核生化灾害防护国家重点实验室开放基金（SKLNBC2019-21）

作者	单位
李俊柯 1，杜家豪 1，邓章轩 1，罗中旭 1，赖金龙 1,2，罗学刚 1,2	1. 西南科技大学生命科学与工程学院，四川绵阳 621010；2. 西南科技大学生物质材料教育部工程研究中心，四川绵阳 621010

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中文摘要:

【目的】研究苔藓植物对铀的积累特性及抗氧化酶系统的应答机制。【方法】采用溶液培养法，用含有不同浓度（0、5、10、15、20 μmol/L）铀溶液处理 3 种苔藓（大灰藓、大灰藓小型变种、砂藓）植株体72 h 后，观察苔藓植物生长状况；测定苔藓植物体内铀累积量及可溶性蛋白、游离脯氨酸（Pro）、丙二醛（MDA）含量；测定过氧化物酶（POD）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）活性。【结果】铀对苔藓植物茎叶有一定的毒害作用，表现为茎叶发黄发黑，出现不同程度的萎缩现象，而对其假根无显著影响；3 种苔藓中，大灰藓小型变种对铀的累积能力最强，在铀浓度为 20 μmol/L 时可达 3 440.67 mg/kg（DW），生物富集系数（BCF）达 0.43。中低浓度铀胁迫（5~10 μmol/L）对 3 类苔藓植物可溶蛋白及脯氨酸含量的累积有一定的促进作用，高浓度铀胁迫（15~20 μmol/L）对其有显著破坏作用。3 种苔藓 MDA 含量随着铀浓度的增加显著上升。3 种苔藓抗氧化酶活性均表现为低浓度（5~10 μmol/L）刺激正向应答，高浓度（15~20 μmol/L）产生抑制作用。【结论】铀胁迫对苔藓植物生长状况、抗氧化酶系统有显著影响。其中，大灰藓对铀胁迫的敏感性高于大灰藓小型变种与砂藓；大灰藓小型变种表现出一定的耐铀能力与富集能力，具有应用于铀矿山苔藓结皮 - 超富集植物联合修复的潜力。

英文摘要:

【Objective】The study aimed to explore the characteristics of uranium accumulation and response mechanism of antioxidant enzyme system in bryophytes【Method】The solution culture method was used in this experiment. The plants of three species of bryophytes〔Hypnum plumaeforme, Hypnum cupressiforme L.ex Hedw. var. cupressiforme, Racomitrium canescens（Hedw.）Brid〕were treated with different concentrations of uranium（0, 5, 10, 15, 20 μmol/L）for 72 h, then the growth statuses of bryophytes were observed. The contents of uranium accumulation, soluble protein, free proline（Pro）and malondialdehyde（MDA）in bryophytes were measured, and the activities of peroxidase（POD）, superoxide dismutase（SOD）and catalase（CAT）were determined.【Result】Uranium had toxic effect on the stems and leaves of bryophytes, showing that the stems and leaves turned yellow and black and shrank in different degrees, but it had no significant effect on their rhizoids. Among the three bryophytes, H. cupressiforme L.ex Hedw.var.cupressiforme had the strongest ability to accumulate uranium, reaching 3 440.67 mg/kg（DW）at uranium concentration of 25 μmol/L, with the BCF of 0.43. The accumulations of soluble protein and proline in three bryophytes were promoted by low and medium concentrations of uranium stress（5-10 μmol/L）, while they were significantly damaged by high concentration uranium stress（15-20 μmol/L）. MDA contents in three bryophytes increased significantly with the increase of uranium concentration. The activities of antioxidant enzymes in three bryophytes showed a positive response to low concentration（5-10 μmol/L）and a inhibitory effect to high concentration（15-20 μmol/L）.【Conclusion】Uranium stress has a significant effect on the growth and antioxidant enzyme system of bryophytes. Among them, the sensitivity of H. plumaeforme to uranium stress is higher than that of H. cupressiforme L.ex Hedw.var.cupressiforme and R. Canescens（Hedw.）Brid. H. cupressiforme L.ex Hedw.var.cupressiforme shows a certain ability of uranium tolerance and enrichment ability, and has the potential to be applied to the joint remediation of moss crust and hyperaccumulation plants in uranium mines.

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