| Arbuscular mycorrhizal fungi(AMF)is a kind of widely exist in nature and can be with most terrestrial plants form symbiotic relationship of soil fungi,many studies have shown that AM plays a positive role in the aspect of plants to adapt to the heavy metal pollution stress.The plant-growth promoting rhizobacteria is a kind of exist in plant rhizosphere range can through own secretion or induced plant growth regulator and so on ways to improve plants(such as drought and salt)in adversity tolerance of beneficial bacteria.Meantime,studies have also shown that arbuscular mycorrhizal fungi together with plant-growth promoting rhizobacteria,have positive effects on plant tolerance to drought and organic pollution(such as oil).However,studies on plant tolerance chromium by inoculating AM fungi and AM fungi cooperating with plant-growth promoting rhizobacteria under different pH are relatively few.In this study,the positive effects of AM and together with plant-growth promoting rhizobacteria on growth and chromium tolerance were confirmed through biomass,physiological index and mineral nutrient absorption.The key results and conclusions are as follows:(1)A pot experiment was conducted to evaluate the effects of Rhizophagus irregularis(BGC AH01)on the growth,toralance of dandelion growth in different pH values soils spiked with chromium.The results indicated that the inoculation of AMF promoted plant growth by increasing the host plant's absorption of mineral nutrients phosphorus,diluted the chromium concentration in the plant,alleviated the toxic effect of chromium on dandelion,reduced the content of proline in the leaves,and improved the tolerance of dandelion to chromium.This study showed that the dandelion biomass was increased by the inoculation of AMF,among which the plant biomass increased the most in the alkaline soil,followed by the acidic soil,and the least in neutral soil;(2)The effects of inoculated with arbuscular mycorrhizal fungi(Rhizophagus irregularis BGC AH01),Bacillus mucilaginosus and co-inoculation on the growth and chromium tolerance of dandelion grown in different pH values soils with exogenous add hexavalent chromium were studied by pot experiment.The results showed that co-inoculation treatment increased mycorrhizal colonization in acidic and neutral soils,while alkaline soil inhibited the activity of Bacillus mucilaginosus.Through Bacillus mucilaginosus soluble phosphorus releasing to soil and AMF to promote plant absorption of phosphorus,potassium,inoculated treatment in acidic and neutral soils and inoculated AMF in alkaline soil promoting the growth of dandelion,increase plant biomass,dilute the chromium concentration in the plant,alleviate the plant's toxicity of chromium,reduces the leaf proline content,improved the tolerance of plants in chromium stress.Meanwhile,the removal rate of soil chromium was improved.The study has demonstrated that the role of arbuscular mycorrhizal fungi and plant-growth promoting rhizobacteria(Bacillus mucilaginosus)on plant growth and chromium tolerance in chromium stress condition,alleviated chromium toxicity to plant through improving plant's phosphorus nutrition,thus improving plant growth and chromium tolerance,and provided some reference for using AM fungi and co-inoculation with plant-growth promoting rhizobacteria in ecological restoration of chromium-contaminated soils with different pH values. |
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