Mitigation of Saline Stress Adverse Effects in Lettuce Plant Using Selenium and Silicon

Abstract

Two field experiments were conducted in the two successive seasons of 2012-2013 and 2013-2014 to investigate the effects of selenium (Se) and silicon (Si) application on two lettuce (lactuca sativa L.) cultivars Great lakes and Balady grown under salt stress (3.22 dSm −1) in irrigation water. Two levels of Se (16 and 32 µM) as sodium selenate and Si (1 and 2 mM) as potassium silicate were used to adverse the destructive effect of salinity. Application of Se and Si improved growth parameters e.g., plant height, root length, number of leaves per plant, plant fresh weight, plant dry weight, chlorophyll a, b and carotenoids content. Si at 2 mM gave the highest significant increase of leaf relative water content (LRWC), accumulation of proline, total soluble sugars (TSS). Treatments also affected the activity of super oxide dismutase (SOD), peroxidase (POD), and the content of K and Ca. However, same treatments decreased lipid peroxidation (MDA), membrane permeability (MP) and Na content.