一株 Cr（Ⅵ）还原菌对 Cr（Ⅵ）胁迫下小白菜幼苗植物毒性及植物有效性的缓解效应

陈土凤; 谢光炎; 许燕滨; 陈鹏程

文章摘要

陈土凤，谢光炎，许燕滨，陈鹏程.一株 Cr（Ⅵ）还原菌对 Cr（Ⅵ）胁迫下小白菜幼苗植物毒性及植物有效性的缓解效应[J].广东农业科学,2020,47(1):77-86

查看全文 HTML 一株 Cr（Ⅵ）还原菌对 Cr（Ⅵ）胁迫下小白菜幼苗植物毒性及植物有效性的缓解效应

Mitigative Effects of a Cr ( Ⅵ ) Reducing Bacterium onPlant Phytotoxicity and Phytoavailability ofPakchoi Seedlings under Cr ( Ⅵ ) Stress

DOI：10.16768/j.issn.1004-874X.2020.01.011

中文关键词: 小白菜植物毒性植物有效性 Cr（Ⅵ）还原菌 Cr（Ⅵ）胁迫

英文关键词: Pakchoi phytotoxicity phytoavailability Cr ( Ⅵ ) reducing bacteria Cr ( Ⅵ ) stress

基金项目:广东省应用型科技研发专项资金（502160007）

作者	单位
陈土凤，谢光炎，许燕滨，陈鹏程	广东工业大学环境科学与工程学院，广东广州 510006

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中文摘要:

【目的】研究 Cr（Ⅵ）还原菌 Exiguobacterium sp. EH5（简称菌株 E）对 Cr（Ⅵ）胁迫下四季青小白菜幼苗的植物毒性及植物有效性的影响。【方法】通过水培盆栽试验，向等体积、含有不同 Cr（Ⅵ）质量浓度（0、1、2、3、4、5 mg/L）的水培营养液中按体积比 1% 添加菌悬液（菌悬液 OD600nm ≈ 4），考察菌株 E 对 Cr（Ⅵ）胁迫下小白菜幼苗的生长量、叶绿素含量、蛋白质含量、丙二醛（MDA）含量、超氧化歧化酶（SOD）活性及铬含量的影响。【结果】（1）Cr（Ⅵ）质量浓度越高，Cr（Ⅵ）毒性抑制小白菜幼苗生长及其蛋白质、叶绿素合成的效果越显著。加入菌株 E 后，在相同最高 Cr（Ⅵ）质量浓度（5 mg/L）对比下，小白菜幼苗茎长、根长、鲜重、叶绿素总量及蛋白质含量比不加菌 E 对照分别增加 98.10%、5.32%、90.49%、10.07%、11.11%。（2）随着 Cr（Ⅵ）胁迫质量浓度升高，小白菜幼苗叶片中 MDA 含量增加，SOD 活性随着 Cr（Ⅵ）质量浓度升高呈先增后降趋势。加入菌株 E 后，在相同质量浓度 1~5 mg/L 下，小白菜幼苗叶片中 MDA 含量比不加菌对照分别降低 19.60%、17.05%、58.85%、28.19%、11.66%。在 Cr（Ⅵ）胁迫质量浓度≤ 4 mg/L 时，加菌株 E 的 SOD 活性比不加菌对照有所降低，随着 Cr（Ⅵ）质量浓度升高（＞ 4 mg/L），加菌株 E 的 SOD 活性比不加菌对照提高 11.51%。（3）Cr（Ⅵ）胁迫质量浓度越高，小白菜幼苗体内（根、茎叶）Cr 含量越高。加入菌株 E 后，小白菜幼苗根、茎叶部分的 Cr 含量比不加菌对照均有不同程度的降低。【结论】添加菌株 E 可以在一定程度上缓解 Cr（Ⅵ）对小白菜幼苗的生长毒性以及 Cr（Ⅵ）诱导的氧化胁迫，并降低小白菜幼苗对 Cr（Ⅵ）的可利用度。

英文摘要:

【Objective】This paper is to study the effects of a Cr ( Ⅵ ) reducing strain Exiguobacterium sp. EH5 (hereinafter called strain E) on the phytotoxicity and phytoavailability of Pakchio seedlings under Cr ( Ⅵ ) stress. 【Method】 The effects of strain E on the growth and concentrations of chlorophyll, protein, malondialdehyde (MDA), superoxide dismutase (SOD) and chromium in Pakchio seedlings under Cr ( Ⅵ ) stress were investigated by pot culture experiment, in which the bacterial suspension with a volume ratio of 1% (bacterial suspension OD600 nm ≈ 4) was added into the hydroponicnutrient solution. 【Result】(1) Under the experimental conditions, when the concentration of Cr ( Ⅵ ) was higher, the Cr ( Ⅵ ) toxicity showed greater inhibition effects on the growth of Pakchio seedlings and their protein and chlorophyll synthesis. After adding strain E, at the same maximum concentration of Cr ( Ⅵ ) (5 mg/L), compared with the group without adding strain E， the stem length, root length, fresh weight, total chlorophyll and protein content of Pakchioi seedlings increased by 98.10%, 5.32%, 90.49%, 10.07% and 11.11%, respectively; (2) With concentration increasing of Cr ( Ⅵ ) stress, the MDA content in the leaves of Pakchoi seedlings increased, the SOD activity was ascend in first and descend at last with concentration of Cr ( Ⅵ ) increasing . After adding strain E, at the same concentration of 1-5 mg/L, the MDA content in leaves of Pakchoi seedlings decreased by 19.60%, 17.05%, 58.85%, 28.19% and 11.66%, respectively, compared with that in group E without adding strain E. When the concentration of Cr ( Ⅵ ) stress was ≤ 4 mg/L, the activity of SOD enzyme in the inoculated group decreased compared with that in the non-inoculated group under the same concentration. Then, with the increase of concentration of Cr ( Ⅵ ) ( ＞ 4 mg/L), SOD activity in the group with strain E was 11.51% higher than that in the non-added group. (3) The Cr content in the roots, stems and leaves of Pakchoi seedlings was higher with the increase of concentration of Cr ( Ⅵ ) stress. After adding strain E, Cr content in the roots, stems and leaves of Pakchoi seedlings decreased compared with that in the group without strain E.【Conclusion】The addition of strain E could alleviate the growth inhibition and oxidative stress from Cr ( Ⅵ ) on Pakchoi seedlings by reducing the bioavailability of Cr ( Ⅵ ) by Pakchoi seedlings.

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