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| 土壤接种棘孢木霉菌降低小油菜砷胁迫及其可能机理 |
| Reliefs the Exposure Stress of Soils Arsenic on Brassica campestris L. Growth and Its Possible Mechanisms by Inoculation of Trichoderma asperellum SM-12F1 |
| 投稿时间：2018-01-05 修订日期：2018-02-08 |
| DOI：10.13254/j.jare.2018.0007 |
| 中文关键词: 砷胁迫，小油菜，棘孢木霉菌，砷形态，抗氧化酶 |
| 英文关键词: arsenic stress, Brassica campestris L., T.asperellum SM-12F1, arsenic speciation, antioxidant enzyme |
| 基金项目:“十三五”国家重点研发计划课题项目（2016YFD0801003） |
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| 摘要点击次数: 2032 |
| 全文下载次数: 1964 |
| 中文摘要: |
| 农田土壤中砷的过量累积会影响作物生长，砷可通过食物链影响人体健康。缓解土壤砷对作物生长的胁迫和累积是亟待解决的科学问题之一。本文以具有高耐砷和砷形态转化能力的棘孢木霉菌为研究材料，通过盆栽试验研究了棘孢木霉菌对外源砷胁迫下小油菜生长的影响及其可能机理。结果表明： 120 mg· kg-1外源砷污染土壤上小油菜生长受到显著抑制，接种棘孢木霉菌可显著促进小油菜生长；接种棘孢木霉菌降低了小油菜对砷的吸收及富集系数，与未接菌污染土相比，小油菜地上部和地下部砷含量分别降低了12.4%和20.2%，砷富集系数降低了7.8%。接种棘孢木霉菌使土壤有效态砷含量降低了15.7%，土壤和小油菜地上部均检测到一甲基砷和二甲基砷，表明接种棘孢木霉菌促进了土壤中砷的甲基化，降低了土壤中砷有效性和小油菜体内砷的毒性。此外，外源砷胁迫下小油菜超氧化物歧化酶和过氧化氢酶活性，以及谷胱甘肽、抗坏血酸及丙二醛含量显著升高，而接种棘孢木霉菌可降低小油菜部分抗氧化胁迫相关酶活性，表明接种棘孢木霉菌有效缓解了砷对小油菜生长的胁迫。研究结果可为今后砷高风险农田的安全利用与风险调控提供材料与技术参考。 |
| 英文摘要: |
| The over-accumulation of arsenic(As)in agricultural soils affects crop growth. Subsequently, the accumulated As can pose risk to human health via food-chain. It is urgent to develop technologies to relief the As exposure stress on crop growth and lower the As uptake by crop. In this study, Trichoderma asperellum SM -12F1, capable of As resistance and speciation transformation was used as experimental material. Pot experiments were conducted to investigate the effects of inoculation on the growth of Brassica campestris L. in As-contaminated soils. The possible mechanisms of inoculation relieving As exposure stress and lowering As uptake were revealed. The results indicated that the growth of Brassica campestris L. was significantly inhibited in soils spiked with As of 120 mg· kg-1. Inoculation could significantly improve the growth of Brassica campestris L. and significantly decreased the As uptake and bioconcentration factor(BCF)of Brassica campestris L. Compared with As-contaminated soils without inoculation, the As contents in the over-and under-ground part of Brassica campestris L. declined by 12.4% and 20.2%, respectively, and the BCF declined by 7.8%. Soil available As contents decreased by 15.7% after inoculation. Methylarsonic acid(MMA)and dimethylarsinic acid(DMA)were detected in water extraction of soil and the shoot of Brassica campestris L. tissues, which indicated that inoculation could trigger soil As methylation and decrease soil As availability and toxicity. Furthermore, inoculation could effectively relief the As exposure stress on Brassica campestris L. growth by the response of antioxidant enzymes. The enzymes in Brassica campestris L. such as superoxide dismutase(SOD)and catalase(CAT), and the contents of glutathione(GSH), ascorbic acid(AsA)and malondialdehyde(MDA), capable of reactive oxygen elimination, significantly enhanced during soil As exposure. However, inoculation lessened the activities or contents of SOD, CAT, GSH, and MDA in Brassica campestris L.. These observations will provide materials and technical reference for the future safe utilization and risk control of As-contaminated soils. |
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