[Arbuscular mycorrhizal fungi enhance cadmium uptake of wetland plants in contaminated water].

Arbuscular mycorrhizal fungi (AMF) play an important role in plant growth enhancement, tolerance to heavy metal toxicity, and rehabilitation of contaminated ecosystems. An experiment was carried out with Phragmites communis and Pennisetum alopecuroides inoculated with or without Funneliformis mosseae (Fm), or Rhizophagus intraradices (Ri) under the simulated wetland system with Cd polluted water (0, 5, 10 or 20 mg·L). The results showed that Cd addition significantly decreased mycorrhizal colonization. AMF increased plant height, dry mass, leaf chlorophyll, N and Cd contents in shoot and root of P. communis and P. alopecuroides, enhanced Cd enrichment capability by roots, and decreased Cd transfer coefficient. Under Cd 5 mg·L treatment, all of the indices in Fm + P. communis combination treatment were higher than those of other treatments, with 60.6% of AMF colonization, and the entry points and vesicles per mm root length were 2.3 and 3.7, respectively. Under the inoculation treatment, dry mass of shoot and root was improved by 69.1%, and 75.0%, nitrogen contents in shoot and root were increased by 38.7% and 27.8%, and the chlorophyll content and plant height were increased by 3.8% and 11.1%, respectively. There was a significant positive correlation between Cd concentration in wetland system and Cd content in shoot and root. Under Cd 20 mg·L treatment, Fm + P. communis combination had the maximum Cd contents of 182.4 mg·kg and 663.3 mg·kg in shoot and root, respectively, the lowest Cd transfer coefficient (0.27), and the highest enrichment coefficient (0.55). In conclusion, Fm + P. communis was the best combination for absorbing Cd in polluted water.