Effects of Salinity on Some Physiological Characteristics of Lepidium sativum L.

Salinity is one of the major environmental stresses, which has deleterious effect on growth, development and yield of crops. Due to the gradual increase in soil and water salinity in the East Azarbaijan province of Iran, the garden cress cultivation in this region has always been associated with many problems. In order to evaluate the tolerance of this plant to different levels of salinity through some physiological characteristics, the present experiment was conducted using randomized complete block design with five treatments consisting of 0, 50, 100, 150 and 200 mM NaCl concentrations and three replications. The results showed that with enhancement in salinity levels, sodium, proline, soluble sugars and carotenoids content increased but potassium content, potassium to sodium ratio and amounts of chlorophyll a and b declined. Salinity had no significant effect on chlorophyll a+b content, chlorophyll a/b ratio and relative water content. Plants were destroyed at 200 mM concentration after 21 days. Since potassium to sodium ratio was lower than 1 at 100 and 150 mM concentrations, continuing of salinity would has presumably led to the destruction of plants in these treatments.