Growth and glucosinolate profiles of a common Asian green leafy vegetable, Brassica rapa subsp. chinensis var. parachinensis (choy sum), under LED lighting

Abstract

Technological advancements in light-emitting diode (LED) technology have led to the production, under controlled indoor conditions, of value-added crops that are high in nutritional or nutraceutical contents. In this study, the growth and glucosinolate (GSL) profiles of a common Asian vegetable, Brassica rapa subsp. chinensis var. parachinensis (choy sum or cai xin) were determined under LED lighting. The growth of choy sum was influenced by both the LED light intensity and spectrum, with plants grown under 160 µmol m-2 s-1 red-blue light (160RB) producing the highest shoot biomass (~100–300% increment in adult plants). GSL content was found to vary across growth stages regardless of LED treatment. Total GSLs per gram fresh weight were four times higher in one-leafed seedlings than in adult plants. A shift from a high proportion of aliphatic GSLs in one-leafed seedlings to indolic and aromatic GSLs in three-leafed seedlings and adult plants was attributed to an increase in the proportion of glucobrassicin and/or 4-hydroxy-glucobrassicin, and gluconasturtiin which are known to have anti-cancer properties. Our results will be useful for the production of GSL-enhanced vegetables through urban farming.