Reversibility Effects of Salinity Stress in Lepidium Sativum: Growth, Resistance State, and Management

Abstract

Salinity is an important stress factor that limits plant growth and productivity. In order to better improve the effects of salinity on the growth state of plants, we decided to perform recovering experiments by following both chemical and physiological parameters in NaCl pre-stressed Lepidium sativum seedlings after NaCl had been removed from the nutrient solution. The work shows that NaCl suppression results in the resumption of growth activity. The increase in leaf biomass is more important than that of the roots. The results indicated that a significant increase in protein, sugar, and proline contents is needed to reach the level obtained with unstressed controls. Additionally, the high endogenous accumulation of Na+ ion decreased significantly after NaCl suppression, especially in roots. Salt ions provoked an increase in the NH4+ concentrations in the leaves and roots, parallel to the high increase of proteolytic enzymes activities involved in the protein degradation. This was in accordance with the pronounced decrease of dry weight by salt in leaves and roots. Also, proteolysis activity decreased during the recovering time. According to the obtained results, we will discuss the ability of the plant to dilute the effects of NaCl toxicity during the recovering period. An important conclusion of this work is that a transient salt accumulation in the culture medium is not necessarily followed by a significant depreciation in product yield and tolerance.