Examining salinity tolerance mechanisms in (sub)tropical grain legumes: Soybean (Glycine max), cowpea (Vigna unguiculata), mungbean (Vigna radiata), and common bean (Phaseolus vulgaris)

The research elucidated physiological responses to different salt types in soybean (Glycine max) and comparative studies with other (sub)tropical grain legumes. Soybean (G. max) and G. soja were more sensitive to high Na+ than high Cl-; mungbean (Vigna radiata) was more sensitive to high Cl- than high Na+; cowpea (Vigna unguiculata) and common bean (Phaseolus vulgaris) were sensitive to both high Na+ and high Cl-. Leaf 'tissue tolerance' and Na+ exclusion contribute to salt tolerance in (sub)tropical grain legumes; and salt tolerance in soybean was associated with the ability to exclude Na+ from the photosynthetically active mesophyll cells.