Effect of salinity and ascorbic acid on growth, water and osmotic relations of Lepidium sativum

Soil salinity is a serious environmental problem in arid and semi-arid regions that have negative impacts on crop production. In this research، because of medicinal and nutritional importance of the garden cress (Lepidium sativum) plant، the interactive effects of salinity (225 mM NaCl) and ascorbic acid (1 mM) were evaluated on growth and its water relations. A completely randomized design with four replications was conducted under controlled conditions. The results showed that salinity decreased growth، relative water content، osmotic potential and soluble proteins and increased soluble sugars، amino acids and proline contents. Many of salinity damaged characteristic were improved by adding exogenous ascorbic acid to salty environment. Exogenous ascorbic acid alone، in comparison with control، enhanced the growth of garden cress by increasing relative water content، soluble sugars and soluble proteins contents. The results indicated that usage of ascorbic acid، as an antioxidant، reduced harmful effects of salinity stress and led to growth improvement in garden cress plants.