Characterising the rhizospheric soil niches of beach plum (Prunus maritima) colonised by arbuscularmycorrhizal fungi and/or phosphate-solubilising fungi when grown under NaCl stress

Abstract

SummaryThe objective of this work was to study the effects of inoculation with an arbuscular mycorrhizal fungus (AMF), Glomus mosseae, and/or a phosphate-solubilising fungus (PSF), Mortierella sp. SM-1, on the rhizospheric niche of beach plum (Prunus maritima) when grown under 1% (w/v) NaCl stress. Salinisation adversely affected colonisation by AMF, microorganism populations, available-P, and hydrolysable-N concentrations in the soil, as well as phosphatase, urease, and proteinase activities in the rhizospheric niche of beach plum, resulting in a significant reduction (P 0.05) in the dry weight (DW) of the plants. Plants inoculated with AMF and/or PSF avoided these adverse changes. Combined inoculation with AMF and PSF promoted AMF colonisation, increased plant DWs, and significantly increased bacterial and actinomycete numbers on the root surface and in roots, and nitrogen-fixing bacterial numbers on the root surface of beach plum plants. Dual inoculation with AMF plus PSF also resulted in significantly higher phosphatase, urease, and protease activities, and higher concentrations of available-P and hydrolysable-N in rhizosphere soil than following a single inoculation with AMF or PSF. After 90 d of 1% (w/v) NaCl stress, soil pH values in the rhizosphere of beach plum plants co-inoculated with AMF plus PSF were significantly lower than in the rhizosphere of plants inoculated with AMF or PSF alone.We conclude that inoculation with AMF plus the application PSF synergistically improved the micro-ecological environment and increased soil fertility in the rhizosphere of beach plum, which improved the tolerance of these plants to saline stress.