Is 5-aminolevulinic acid concentration in plants related to soil salinity? A test with 17 native species of Bahrain

•ALA is specific to plants regardless of locations, habitats, and soil salinity.•No correlation was observed between soil salinity and ALA in plants studied.•ALA of desert and mangrove plants was significantly different at P < 0.05.•ALA a compatible organic solute produced in high quantity to avoid water deficit.

The objective of this study was to determine the effect of soil salinity on the concentration of ALA in 17 native plants species collected from different locations across the Kingdom of Bahrain. ALA was extracted from the various plant species and measured by flourometric analysis. ALA concentrations ranged between 21.53 ± 2.05 μg g−1 and 66.03 ± 4.42 μg g−1. The highest ALA concentration was found to be in Aizoon canariense whereas the lowest concentration was recorded in Avicennia marina. Significant difference (P < 0.05) in ALA concentration among all plant species was found between 108 out of 136 possible combinations (79.4%). Furthermore, ALA concentrations of desert and mangrove plants only were found to be significantly different at P < 0.05. However, no correlation was observed between soil salinity and ALA concentrations in any of the plant species studied. Therefore, the results of this study suggest that the main role of internal ALA in plants' is to maintain plant specific chlorophyll content and photosynthetic parameters regardless of soil salinity.