Plant Process and Function

en Salt tolerance of sweet clover in response to application of ascorbic acid, proline and urea Salt tolerance of sweet clover in response to application of ascorbic acid, proline and urea تنش شوري Salt Stress پژوهشي Research <div dir="ltr">Cost-effective exogenous application of some metabolites (ascorbic acid and proline) and nutrients (e.g. nitrogen) may help to minimize the harmful effects of salinity. This split-plot research was tackled to evaluate the impact of ascorbic acid (5 mM), proline (20 mM), and urea (46%N) on the alleviation of osmotic, ionic, and oxidative stresses of non-saline and 6.7 dS/m salinity in Melilotus officinalis according to a 2-year experiment at Urmia University. Salt stress increased the activities of superoxide dismutase, glutathione peroxidase, Phenylalanine ammonia-lyase and the amounts of malondialdehyde, peroxide hydrogen, flavonoids, sodium, potassium and calcium in leaves. The proline, potassium, calcium and relative water contents, activities of catalase and ascorbate peroxidase, plant biomass and seed yield were decreased at salinity. In salt-treated plants, foliar sprays of proline enriched the leaf cells with K+ ions and reduced the Na+/K+ ratio, leading to increased relative water content. Foliar sprays of urea increased the proline content, flavonoids, relative water content, and antioxidant enzyme activities that lead to reducing oxidative damage. These findings exhibited the beneficial effects of foliar-applied urea and proline that led to considerable improvement in salt tolerance through biochemical responses.</div> Cost-effective exogenous application of some metabolites (ascorbic acid and proline) and nutrients (e.g. nitrogen) may help to minimize the harmful effects of salinity. This split-plot research was tackled to evaluate the impact of ascorbic acid (5 mM), proline (20 mM), and urea (46%N) on the alleviation of osmotic, ionic, and oxidative stresses of non-saline and 6.7 dS/m salinity in Melilotus officinalis according to a 2-year experiment at Urmia University. Salt stress increased the activities of superoxide dismutase, glutathione peroxidase, Phenylalanine ammonia-lyase and the amounts of malondialdehyde, peroxide hydrogen, flavonoids, sodium, potassium and calcium in leaves. The proline, potassium, calcium and relative water contents, activities of catalase and ascorbate peroxidase, plant biomass and seed yield were decreased at salinity. In salt-treated plants, foliar sprays of proline enriched the leaf cells with K+ ions and reduced the Na+/K+ ratio, leading to increased relative water content. Foliar sprays of urea increased the proline content, flavonoids, relative water content, and antioxidant enzyme activities that lead to reducing oxidative damage. These findings exhibited the beneficial effects of foliar-applied urea and proline that led to considerable improvement in salt tolerance through biochemical responses. Flavonoids, Malondialdehyde, Melilotus officinalis, Osmolytes, Oxidative stress, Saline soil Flavonoids, Malondialdehyde, Melilotus officinalis, Osmolytes, Oxidative stress, Saline soil 71 78 http://jispp.iut.ac.ir/browse.php?a_code=A-10-690-4&slc_lang=en&sid=1 Sajad Rahimi Sajad Rahimi sajadrahimi693@gmail.com No Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia- Iran Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia- Iran Alireza Pirzad Alireza Pirzad a.pirzad@urmia.ac.ir Yes Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia- Iran Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia- Iran Jalal Jalilian Jalal Jalilian j.jalilian@urmia.ac.ir No Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia- Iran Department of Plant Production and Genetics, Faculty of Agriculture, Urmia University, Urmia- Iran Saeedeh Rahimzadeh Saeedeh Rahimzadeh srahimzadeh9@gmail.com No Department of Plant Eco-physiology, Faculty of Agriculture, University of Tabriz, Tabriz, Iran Department of Plant Eco-physiology, Faculty of Agriculture, University of Tabriz, Tabriz, Iran