Su Shiming, Zeng Xibai, Bai Lingyu, Williams Paul N, Wang Yanan, Zhang Lili, Wu Cuixia
Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment, Ministry of Agriculture, Beijing, PR China.
Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment, Ministry of Agriculture, Beijing, PR China.
Chemosphere. 2017 May;175:497-504. doi: 10.1016/j.chemosphere.2017.02.048. Epub 2017 Feb 9.
Arsenic (As)-contaminated agricultural soils threaten crop yields and pose a human health risk. Augmentation of exogenous microorganisms exhibiting plant-growth promoting and As speciation changing shows potential to improve crop growth and change soil As availability. Trichoderma asperellum SM-12F1 exhibiting both traits was developed into chlamydospores to improve its persistence in contaminated soils. After inoculation, As availability and enzyme activity in two types of soils and the growth as well as As uptake of water spinach (Ipomoea aquatic Forsk.) were investigated. The results indicated that inoculation significantly improved water spinach growth in both soils. Inoculating chlamydospores at 5% significantly increased As concentration (139%), bioconcentration factor (150%), and translocation factor (150%) in water spinach grown in Chenzhou (CZ) soils, while no significant change for these in Shimen (SM) soils. Inoculating chlamydospores at 5% caused a significant increase (16%) of available As content in CZ soils, while a significant decrease (13%) in SM soils. Inoculation significantly caused As methylation in both soils, while significant As reduction merely observed in CZ soils. The differential changes in available As contents in both soils were attributed to the soil pH, As fractionations and speciation characteristics. Furthermore, Inoculating chlamydospores at 5% significantly improved the activities of β-glucosidase (155%), chitinase (211%), and phosphatase (108%) in SM soils, while significant decreases in β-glucosidase (81%), phosphatase (54%), aminopeptidase (60%), and catalase (67%) in CZ soils. Bioaugmentation and As availability change were responsible for this result. These observations will be helpful for the application of fungal chlamydospores in the future bioremediation.
受砷（As）污染的农业土壤威胁着作物产量，并对人类健康构成风险。增强具有促进植物生长和改变砷形态功能的外源微生物，显示出改善作物生长和改变土壤砷有效性的潜力。兼具这两种特性的棘孢木霉SM-12F1被制成厚垣孢子，以提高其在污染土壤中的持久性。接种后，研究了两种土壤中砷的有效性和酶活性，以及空心菜（Ipomoea aquatic Forsk.）的生长和砷吸收情况。结果表明，接种显著促进了两种土壤中空心菜的生长。在郴州（CZ）土壤中种植的空心菜，接种5%的厚垣孢子显著提高了砷浓度（139%）、生物富集系数（150%）和转运系数（150%），而在石门（SM）土壤中这些指标无显著变化。接种5%的厚垣孢子使CZ土壤中有效砷含量显著增加（16%），而在SM土壤中显著降低（13%）。接种在两种土壤中均显著导致砷甲基化，而仅在CZ土壤中观察到显著的砷还原。两种土壤中有效砷含量的差异变化归因于土壤pH值、砷的形态和形态特征。此外，接种5%的厚垣孢子显著提高了SM土壤中β-葡萄糖苷酶（155%）、几丁质酶（211%）和磷酸酶（108%）的活性，而在CZ土壤中β-葡萄糖苷酶（81%）、磷酸酶（54%）、氨肽酶（60%）和过氧化氢酶（67%）显著降低。生物强化和砷有效性变化导致了这一结果。这些观察结果将有助于真菌厚垣孢子在未来生物修复中的应用。
