Growth and nutrient level of water spinach (Ipomoea aquaticaForssk.) in response to LED light quality in a plant factory

Abstract

Water spinach (Ipomoea aquatica Forssk.) is widely cultured as an edible green leafy vegetable in Asian countries. Its leaves contain adequate quantities of vitamins, minerals, plant fiber, amino acids, and antioxidant components. It has also been used as a traditional medicine for treating swelling, food poisoning, and antioxidant-related disorders. A plant factory with an artificial lighting system as a fully environment controllable facility has been used for year-round high quantity and quality production of leafy vegetables, herbs, and medicinal plants. This study aimed to investigate the growth and nutrient level in water spinach plants as affected by different LED light qualities in the plant factory. Plants were grown under six light conditions (white, white with far red, blue, red, blue+red, and blue+red with far red), at a PPFD of 200 µmol m(-2) s(-1) for 3 weeks after transplanting. The highest shoot weight, root biomass production, total leaf area, side-shoot development, and ascorbic acid content in shoot were observed in blue light treatment. Different light qualities influenced biomass distributions in plant leaf and stem. Red light increased plant stem length and stem dry mass with a decrease in leaf dry mass. Higher blue ratio (>50%) lights enhanced antioxidant activity in plant shoots, mainly due to a significant increase in stem rather than in leaves.