Arbuscular mycorrhizal fungi (AMF) promote the growth of the pioneer dune plant of coastal areas

Salinity is the primary restriction factor for vegetation conservation and the rehabilitation of coastal areas in Eastern China. Arbuscular mycorrhizal fungi (AMF) have been proved to have the ability to alleviate salt stress in plants. However, the role of AMF in relieving salt stress among indigenous trees species is less well known, limiting the application of AMF in the afforestation of local area. In this study, a salt-stress pot experiment was conducted to evaluate the effects of AMF on Zelkova serrata (Thunb.) Makino, a tree species with significant potential for afforestation of coastal area. The Z. serrata seedlings inoculated with three AMF strains (Funneliformis mosseae 1, Funneliformis mosseae 2, and Diversispora tortuosa) were subjected to two salt treatments (0 and 100 mM NaCl) under greenhouse conditions. The results showed that the three AMF strains had positive effects, to a certain extent, on plant growth and photosynthesis under normal condition. However, only F. mosseae 1 and F. mosseae 2 alleviated the inhibition of growth, photosynthesis, and nutrient uptake of Z. serrata seedlings under salt stress. The two AMF strains mitigated salt-induced adverse effects on seedlings mainly by increasing the leaf photosynthetic ability and biomass accumulation by reducing Na+ content, increasing P, K+, and Mg2+ content, as well as by enhancing photosynthetic pigments content and the stomatal conductance of leaves. These results indicated that AMF inoculation is a promising strategy for the afforestation of coastal areas in Eastern China.

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Physiological mechanism of enhancing salinity tolerance of Gleditsia sinensis Lam. by arbuscular mycorrhizal fungi

10.21203/rs.2.18799/v1 ◽

2019 ◽

Author(s):

Jinping Wang ◽

Bo Zhang ◽

Jinchi Zhang ◽

G. Geoff Wang ◽

Jie Lin ◽

...

Keyword(s):

Arbuscular Mycorrhizal Fungi ◽

Salinity Tolerance ◽

Mycorrhizal Fungi ◽

Physiological Mechanism ◽

Arbuscular Mycorrhizal ◽

P Uptake ◽

Coastal Areas ◽

Protective Effects ◽

Mycorrhizal Dependency ◽

Gleditsia Sinensis

Abstract Background and AimsThe protective effects of arbuscular mycorrhizal fungi (AMF) on salt-stressed crop plants had been well studied. However, the physiological mechanism of AMF in mitigating adverse impact caused by salinity stress in different tissues of woody plants is not clear. Gleditsia sinensis Lam. is a valuable tree species with various phamaceutical uses; however, high soil NaCl concentration limits its growth in saline soil including coastal areas. This study aimed to investigate the effects of AMF on G. sinensis salinity tolerance and reveal its underlying physiological mechanism.MethodsA greenhouse experiment was performed. G. sinensis seedlings with and without AMF inoculation were subjected to four salinity levels (0, 50, 100, and 150 mM NaCl). After 2 months, the seedlings were harvested and analyzed for growth and biochemical parameters.ResultsHigh AMF colonization rates (over 95%) and high mycorrhizal dependency (over 75%) were observed across all NaCl levels, and AMF-inoculated plants presented significantly higher aboveground and below ground growth than non-inoculated plants. AMF effectively enhanced the salinity tolerance of G. sinensis seedlings by enhancing leaf gas exchanges inducing higher leaf net photosynthetic rates; improving peroxidase, catalase, and superoxide dismutase activities resulting in higher membrane stability indexes and lower malondialdehyde contents in leaves and roots; increasing P uptake and P/N ratio to mitigate P-limited biomass products; selectively absorbing less Na + and more Ca 2+ in their tissues to alleviate ion toxicity and maintain more favorable ion balances (e.g., K + /Na + ) in their tissues.ConclusionsThe results suggested the feasibility of using AMF to improve salinity tolerance as well as afforestation and rehabilitation of G. sinensis in coastal areas.

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