Light Intensity Plays Contrasting Roles in Regulating Metabolite Compositions in Choy Sum (Brassica rapa var. parachinensis)

Abstract

Light intensity can be an efficient tool in regulating leafy vegetable quality and yet little is known mechanistically hitherto. In this study, choy sum metabolic responses to progressively increasing white light intensity were investigated in terms of its essential metabolites including chlorophylls, carotenoids, phenolic compounds, and glucosinolates. Significant enhancements were observed in choy sum’s nutritional quality like the total phenolic content and antioxidant capacity under a high intensity of light. However, progoitrin was significantly increased by up to 7.54-fold under a low light intensity of 50 μmol/(m2·s) compared with high light intensity, presenting a unique virus/pest-prevention strategy of choy sum under poor growth status. Pearson’s correlation analysis revealed a linear relationship between the light intensity and some metabolites. Principal component analysis further confirmed such contrasting roles of light intensity. The new knowledge gained about light-influenced choy sum metabolite levels can be critical in directing farmers in indoor farming practice for improving vegetable nutritional values.

Performance evaluation of a novel adjustable lampshade-type reflector (ALR) in indoor farming practice using choy sum (Brassica rapa var. parachinensis)

“…After centrifugation, the supernatant was collected, and its absorbance was scanned from 200 to 780 nm to obtain the values at 663.6, 646.6, and 440.5 nm, respectively, by using a UV-vis spectrophotometer (UV1800, Shimadzu, Japan). The chla, chlb, and TC contents were finally calculated using the following equations (mg per gram DW) (Huang et al, 2021a):…”

“…The mixture was then sonicated in an ice bath for 15 min and centrifuged at 20,000 × g for 10 min at 4°C to collect the supernatants. The above-mentioned procedure was repeated twice, and the supernatants were pooled and then stored at -80°C prior to further analyses for TPC and antioxidant capacity (Huang et al, 2021a).…”

“…After the effectiveness of ALR on improving the key environmental conditions on a cultivation shelf was confirmed, validating the performance of ALR in real plant cultivation on the shelf would be essential to eventually prove that this reflector offers benefits to an indoor plant factory. As such, a popular leafy vegetable rich in bioactive metabolites and widely cultivated in Asia, choy sum, was chosen as the experimental plant (Liang et al, 2018;Huang et al, 2021a).…”

“…This situation urged people to develop efficient methods to produce more food (Satterthwaite et al, 2010;Benke and Tomkins, 2017). Vegetables, especially leafy green vegetables, have been shown to present a variety of bioactive metabolites such as carotenoids, phenolic compounds, vitamins, and glucosinolates that could benefit human health and supplement daily nutritional needs Liang et al, 2018;Lee et al, 2020;Huang et al, 2021a;Du et al, 2022). Vegetables are traditionally cultivated by using outdoor farming methods such as the conventional flat planting approach.…”

Light-Time-Biomass Response Model for Predicting the Growth of Choy Sum (Brassica rapa var. parachinensis) in Soil-Based LED-Constructed Indoor Plant Factory for Efficient Seedling Production

“…The consumption of vegetables has been an integral part of the human diet due to their many health-promoting functions, such as providing dietary fiber as roughage, a variety of bioactive substances, e.g., carotenoids, phenolic compounds, vitamins, and glucosinolates, contained under different levels, as well as their abilities to enhance satiety and promote the absorption of other macronutrients in the intestinal tract ( Zhang et al, 2011 ; Samoulienë et al, 2013 ; Kwack et al, 2015 ; Walsh et al, 2015 ; Peluso et al, 2016 ; Padayachee et al, 2017 ; Yahia et al, 2017 ; Liang et al, 2018 ; Tan et al, 2020 ; Huang et al, 2021 ). However, traditional cultivation methods, which account for the bulk of vegetable production, tend to be inefficient and unreliable due to the constant fluctuations in sunlight, which is the main source of light energy for such methods ( Alvino and Barbieri, 2016 ).…”