Enhancing Head Lettuce Growth and Quality under Water Stress with Proline, Melatonin and Vermicompost Applications

Abstract

Two field experiments were done in order to reduce the effect of water stress on head lettuce, therefore this study were conducted to impact the influence of vermicompost soil addition and foliar application of proline and melatonin on growth (fresh, dry weights, leaf area, relative water content, numbers of outer leaves, in addition chlorophyll a, b, and carotene contents), yield (head height, head diameter, head weight and total yield), and quality (total dissolved solids (TDS), total carbohydrates, crude protein, total sugar, crude fibers percentages, vitamin C, vitamin E, nitrate (NO3), nitrite (NO2), proline, super oxidase dismutase, peroxidase and catalyse) of head lettuce (lactuca sativa) cv Kharga under water stress (100, 75 and 50% of full irrigation). The results showed the combined treatment of vermicompost and foliar spray with proline under 75% of full irrigation provided the highest vegetative growth, photosynthetic pigments, head yield and quality relative to other treatments including plants grown full irrigation without vermicompost and foliar spray with tap water treatments. These results suggest that yield and quality of head lettuce could be improved under abiotic stress including water scarcity through application of proline, melatonin and vermicompost, additionally these treatments could save water quantities.