INTERACTIVE EFFECTS OF SALINITY STRESS AND NICOTINAMIDE ON PHYSIOLOGICAL AND BIOCHEMICAL PARAMETERS ON FABA BEAN PLANT

A possible survival strategy of plants under saline conditions is to use some compounds that could alleviate salt stress effect. One of these compounds is nicotinamide. The effect of exogenously application of nicotinamide with different concentrations (0, 200 and 400 mg/l) on Vicia faba L. plant against different NaCl treatments (0, 50 and 100 mM NaCl) was investigated at the wire house of the National Research Centre, Cairo, Egypt. Salinity stress reduced significantly plant height, dry weight of shoot, photosynthetic pigments, polysaccharides, total carbohydrates, total-N contents of shoot, seed yield, total carbohydrates & total crude protein of the yielded seeds compared with those of the control plants. In contrast, salinity induced marked increases in sucrose, total soluble sugars, total free amino acids, proline, lipid peroxidation product (MDA) and some oxidative enzymes (polyphenol oxidase and peroxidase enzymes). Also, salinity stress increased Na+ contents with the decreases of other macro and micro elements contents (P, K+, Mg+, Ca2+, Fe2+, Mn2+, Zn2+ and Cu2+) of shoots and the yielded seeds of faba bean. Foliar spraying of nicotinamide alleviated the adverse effects of salinity stress through increased plant height, dry weight of shoot, photosynthetic pigments, polysaccharides, total carbohydrates, total-N contents of shoot and seed yield as well as, sucrose, total soluble sugars, total free amino acids and proline, compared with those of the corresponding salinity levels, while decreased lipid peroxidation product as MDA and the oxidative enzymes (polyphenol oxidase and peroxidase enzymes). Nicotinamide inhibited the uptake of Na+ and accelerated the accumulation of P, K+ , Mg+, Ca2+, Fe2+, Mn2+, Zn2+ and Cu2+ contents in the shoots of salt stressed plants and enhanced total carbohydrate and total crude protein percentage and solutes concentrations in seeds of salinity treated plants