Impact of Ascorbic Acid on Seed Germination, Seedling Growth, and Enzyme Activity of Salt-Stressed Fenugreek

Fenugreek (Trigonella foenum-graecum) seeds soaked in ascorbic acid had increased germination, seedling shoot length and total chlorophyll under salt stress as compared with seeds not treated with ascorbic acid. Root length, fresh weight, dry weight, proline, and catalase activity (CAT) increased in salt stressed seedling in which seeds were not treated with ascorbic acid. In seeds treated with ascorbic acid, the salt stress effect on CAT activity was decreased. Ascorbic acid pretreatment of seeds counteracted the decrease in ascorbate oxidase (AO) induced by salt stress, but appeared to act synergistically with salt stress to decrease proline dehydrogenase. The application of ascorbic acid to fenugreek seed apparently increased antioxidant activity, leading to an increase in resistance to salt stress. Salt stress and the ascorbic acid treatment of seeds led to metabolic changes in seedlings as evidenced by changes in peroxidase (Prx) and esterase (Est) isozymes associated with increases in salt and ascorbic acid concentrations. Such changes could account for increases in seedling vigor with ascorbic acid seed treatment and the ability of the seedling to grow in the presence of a salt stress.