title: The Combined Effects of Arbuscular Mycorrhizal Fungi (AMF) and Lead (Pb) Stress on Pb Accumulation, Plant Growth Parameters, Photosynthesis, and Antioxidant Enzymes in Robinia pseudoacacia L.
abstract: Arbuscular mycorrhizal fungi (AMF) are considered as a potential biotechnological tool for improving phytostabilization efficiency and plant tolerance to heavy metal-contaminated soils. However, the mechanisms through which AMF help to alleviate metal toxicity in plants are still poorly understood. A greenhouse experiment was conducted to evaluate the effects of two AMF species (Funneliformis mosseae and Rhizophagus intraradices) on the growth, Pb accumulation, photosynthesis and antioxidant enzyme activities of a leguminous tree (Robinia pseudoacacia L.) at Pb addition levels of 0, 500, 1000 and 2000 mg kg(-1) soil. AMF symbiosis decreased Pb concentrations in the leaves and promoted the accumulation of biomass as well as photosynthetic pigment contents. Mycorrhizal plants had higher gas exchange capacity, non-photochemistry efficiency, and photochemistry efficiency compared with non-mycorrhizal plants. The enzymatic activities of superoxide dismutase (SOD), ascorbate peroxidases (APX) and glutathione peroxidase (GPX) were enhanced, and hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents were reduced in mycorrhizal plants. These findings suggested that AMF symbiosis could protect plants by alleviating cellular oxidative damage in response to Pb stress. Furthermore, mycorrhizal dependency on plants increased with increasing Pb stress levels, indicating that AMF inoculation likely played a more important role in plant Pb tolerance in heavily contaminated soils. Overall, both F. mosseae and R. intraradices were able to maintain efficient symbiosis with R. pseudoacacia in Pb polluted soils. AMF symbiosis can improve photosynthesis and reactive oxygen species (ROS) scavenging capabilities and decrease Pb concentrations in leaves to alleviate Pb toxicity in R. pseudoacacia. Our results suggest that the application of the two AMF species associated with R. pseudoacacia could be a promising strategy for enhancing the phytostabilization efficiency of Pb contaminated soils.
authors.affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China.|College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Yurong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Plant Systems Biology Lab, Botany and Plant Science, School of Natural Sciences, National University of Ireland, Galway, Ireland.
authors.forename: Xiaozhen
authors.initials: X
authors.lastname: Han
authors.affiliation: Joint BioEnergy Institute, 5885 Hollis St, Emeryville, California 94608, United States of America.|Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States of America.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liang
authors.affiliation: School of Energy Science and Engineering, PK Sinha Centre for Bioenergy, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Ghosh
authors.affiliation: College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Tang
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D000075322:Heavy Metal Poisoning; D007854:Lead / Q000032:analysis / Q000378:metabolism*; D038821:Mycorrhizae / Q000502:physiology*; D010788:Photosynthesis / Q000502:physiology*; D063245:Plant Development / Q000502:physiology*; D011041:Poisoning; D031301:Robinia / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology*; D013312:Stress, Physiological
chemical_list: D000975:Antioxidants; D007854:Lead