Effects of arbuscular mycorrhiza inoculation on plant growth, biological and physiological parameters and mineral nutrition in pepper grown under different salinity and p levels

A study was conducted in a greenhouse, to investigate the effects of arbuscular mycorrhizal fungi (Glomus intraradices), soil salinity and P availability on growth (leaf area and dry weight), nutrient absorption and ion leakage, chlorophyll, soluble sugar and proline content and alkaline phosphatase activity of pepper plants (Capsicum annuum L.). Plants were grown at four levels of salinity (0, 50, 100 and 200 mM NaCl) and two P levels (10 and 40 mg kg-1). Colonisation was 80% to 51% in non-stressed and high salt-stressed plants, respectively. The mycorrhizal dependency was high and only reduced at the higher salinity level. Mycorrhizal plants maintained greater root and shoot biomass at all salinity levels compared to non-mycorrhizal plants, regardless the P level. Interactions between salinity, phosphorous and mycorrhizae were significant for leaf area, root and shoot dry mass. Non-mycorrhizal plants accumulated higher Na and lower K and P compared to mycorrhizal plants. The cell membrane integrity was greater in mycorrhizal plants than in non-mycorrhizal ones. The proline content increases with increasing salt stress and was significantly higher in leaves than in roots. The results indicate that the mycorrhizal inoculation is capable of alleviating the damage caused by salt stress conditions on pepper plants, to maintaining the membranes stability and plant growth, and this could be related to P nutrition.