Response of Miscanthus sacchariflorus to zinc stress mediated by arbuscular mycorrhizal fungi

- Arbuscular mycorrhizal fungi (AMF) promote growth of Miscanthus sacchariflorus.
- AMF inoculation helps M. sacchariflorus to absorb Zn from Zn-deficit soil.
- AMF inoculation protects M. sacchariflorus from Zn toxicity by binding Zn in root tissue.
- AMF mediated M. sacchariflorus can be used in Zn phytoremediation.

Arbuscular mycorrhizal (AM) fungi have the ability to promote growth of the associated plants by enhancing water and nutrient uptake. In the present study, we aimed to explore the performance of Miscanthus sacchariflorus under different soil zinc (Zn) levels in association with inoculated AM fungi. M. sacchariflorus was grown in a greenhouse with three doses of added Zn (0, 100 and 1000 mg kg−1 soil) in combination with or without association of AM fungi, and its growth, oxidative stress levels, and ultrastructure were observed. The additions of medium levels of Zn (100 mg kg−1) did not show significant effects on mycorrhizal colonization; however, when the Zn addition level was 1000 mg kg−1, the mycorrhizal infection rate slightly decreased in comparison to the no Zn addition treatment (control). Inoculation of AM with 100 mg kg−1 Zn addition increased chlorophyll concentration, Fv/Fm, total dry mass, concentrations of indole acetic acid, total nitrogen and total phosphorus, and content of Zn, whereas activity levels of peroxidase and indole acetic acid oxidase, and H2O2 levels were low when compared with the other two treatments. 1000 mg kg−1 Zn addition resulted in lower Zn contents in the aerial parts of inoculated compared to non-inoculated plants. Zn crystals in the root parenchyma of mycorrhizal plants were observed. These results open the possibility of using arbuscular mycorrhizal fungi symbiotic Miscanthus plants in phytoremediation as well as to grow them in Zn-deficient soils.