Rhizophagus intraradices improves arsenic tolerance in Sophora viciifolia Hance

Abstract

Abstract Purpose Arbuscular mycorrhizal fungi (AMF) are capable of protecting host plants against heavy metal toxicity, whereas rare knowledge has been acquired on the underlying effects of AMF on woody leguminous species under arsenic (As) stress. This study was aimed that whether AMF inoculation improves the As tolerance in Sophora viciifolia (a king of leguminous shrub). Methods S. viciifolia seedlings were inoculated with AMF Rhizophagus intraradices, and then the seedlings were grown at three levels (0, 50, and 100 mg As kg−1 soil) of As-polluted soil by performing the potted experiments. The plant growth, photosynthetic parameter, oxidative damage, antioxidant enzyme activities and gene expression of phytochelatin synthase in R. intraradices- and non-inoculated S. davidii seedlings under the different levels of As stress were analyzed. Result Compared with non-inoculated S. viciifolia at the identical As level, R. intraradices-inoculated S. viciifolia were higher in the shoot and root dry weight, plant height, root length, photosynthetic rate, stomatal conductance, transpiration rate, maximal photochemical efficiency of PSII photochemistry, actual quantum yield, and photochemical quenching values, while the intercellular CO2 concentration and non-photochemical quenching values were lower. As-induced oxidative stress generating malondialdehyde, hydrogen peroxide and superoxide in the S. viciifolia leaves and roots reduced significantly by R. intraradices inoculation, whereas the activities of antioxidative enzymes (e.g., superoxide dismutase, peroxidase, and catalase) in S. viciifolia leaves and roots were increased by R. intraradices inoculation. Notably, R. intraradices inoculation up-regulated the gene expression of S. viciifolia phytochelatins in the leaves and roots. Conclusion These results demonstrated that R. intraradices inoculation enhanced the As tolerance in S. viciifolia seedlings by improving the plant growth, gas exchange, chlorophyll fluorescence, reactive oxygen species, antioxidant enzymes and gene expression of S. viciifolia phytochelatins. The present study verified a multifarious positive role of AMF for woody leguminous species under As stress.

Keywords

• Arbuscular mycorrhizal fungi
• Sophora davidii
• Arsenic stress
• Photosynthesis
• Reactive oxygen species
• PCS1 gene expression