Beneficial effects of exogenous selenium, glycine betaine and seaweed extract on salt stressed cowpea plant

Pot experiments in sandy soil were carried out to investigate foliar applications of [selenium (5 10 μM Se), glycine betaine (5 10 mM GB) and seaweed extract (2 4% SWD)] on cowpea plant, under salt stress (0 50 mM NaCl). Growth, yield parameters and biochemical constituents were determined. The obtained results indicated that all foliar treatments under both salinity concentrations achieved an increment in most of the growth, yield parameters and biochemical constituents. As for the effect of single treatment on growth and yield parameters, 5 μM Se without salinity revealed higher significant values than all treatments followed by 10 μM Se under 50 mM NaCl. Meanwhile, 4% SWE under 50 mM NaCl showed the highest values of photosynthetic pigments, proline and Phenylalanine ammonia lyase (PAL). On the other hand, 10 mM GB 50 mM under NaCl recorded the highest value of total soluble sugars (TSS), while a significant increase in protein concentrations was observed by 5μM Se without salinity.