低镉浓度下丛枝菌根真菌对植物的保护作用

Protective effects of arbuscular mycorrhizal fungi on plants under low concentration of cadmium

摘要:

为探讨生物固定技术在低镉污染土壤中的原位利用和水稻安全生产中的应用，采用盆栽试验的方法对比分析了低镉污染条件下接种丛枝菌根真菌(AMF)与否对水稻生长及籽实镉含量的影响.结果表明：低镉污染条件下，AMF可与水稻形成良好的共生关系，宿主水稻菌根依赖性指数达120.43%;AMF侵染可促进植物地下器官的扩张，增加根系的吸收与吸附能力，AMF侵染下水稻的株高、根长、根冠比等营养生长指标均高于非侵染植物水稻，尤其是根冠比提高达22.37%，接种菌剂可以显著增加水稻营养器官生物量，接种菌剂组较空白对照组水稻籽实产量平均提高12.61%；菌剂的施加使水稻籽实镉含量符合国家食品安全标准的土壤安全生产阈值由0.20 mg/kg提高到0.32 mg/kg, 对于保障低镉污染土壤的原位利用和水稻安全生产有重要意义.

Abstract:

To investigate the biological fixation in the application of low cadmium contaminated soil and in-situ utilization of rice safe production, this study adopts the pot experiment to compare and analyze the impact of arbuscular mycorrhizal fungi (AMF) on rice growth and seed cadmium content under low cadmium contamination conditions. The results showed that under the conditions of low cadmium contamination, rice and AMF formed a good symbiotic relationship, and the mycorrhizal dependency index of the host rice reached 120.43%. AMF infection can promote the expansion of the underground plant organs, and increase the adsorption capacity of roots. With AMF infection, the vegetative growth indicators, including rice plant height, root length, ratio of root to shoot, were higher than non-infected rice plants, especially the ratio of root to shoot increased up to 22.37%. Therefore, inoculum can significantly increase the rice nutrition biomass. Compared with the blank control group, the yield of rice seed increased by 12.61%. With the application of the mocrobial inoculim, the soil cadmium content threshold for ational food safety standards of rice seed increased from 0.20 mg/kg to 0.32 mg/kg, which guaranteed the in situ utilization of the low cadmium contaminated soil and the production safety of rice.