Postharvest Quality of Lettuce (Lactuca Sativa L.) as Influenced by Salinity Stress

Abstract

Salinity is one of the abiotic stresses and one of the major constraints to plant growth, development, productivity, postharvest quality, and nutrition. Plant responses to high salinity affects its morphological and developmental aspects of growth as well as its physiological and biochemical processes. Lettuce is an important crop for human diet; however, it is moderately sensitive to salinity stress. Hence, this study was conducted to examine the response of lettuce to different salinity levels. The study was laid out in Randomized Complete Block Design (RCBD) replicated three times with five sodium chloride (NaCl) concentrations as treatments. This includes the control (water); 500 parts/million (ppm); 1,000 ppm; 5,000 ppm; and10,000 ppm. Results show that salinity stress did not significantly influence on yield, leaf moisture content, color deterioration, percent weight loss, wilting, texture, and Visual Quality Rating (VQR) of harvested lettuce. Furthermore, it also did not significantly influence on some biochemical properties specifically on initial pH and initial titratable acidity (TA), final total soluble solids (TSS) and TA, leaf chlorophyll, sugar, and starch content. Lettuce planted on potting media with various levels of salinity during it growth and development until harvesting significantly obtained a significantly lower initial TSS during postharvest analysis than those lettuce planted in potting media without any added salt content. Therefore, lettuce can still survive when planted in soil containing up to 10,000 ppm NaCl without impairing its growth, yield, physical characteristics, and some biochemical properties of harvested lettuce specifically on TA, chlorophyll, sugar, and starch content.