RESUMEN
Little is known about how exactly light plays its role in the growth of choy sum (Brassica rapa var. parachinensis), a widely cultivated vegetable in Asia. By applying a commercial soil using black peat as major constituent with 17:10:14 ratio of NPK fertilizer in this study, the growth responses of choy sum seedling to progressively increasing white LED light intensity in an indoor plant factory were investigated, where positive enhancements were observed in choy sum morphology and growth including both dry and fresh mass accumulation under higher light intensity till 400 µmol/(m2â s), then a reduction occurred due to light oversaturation and overheat. In indoor plant factory, the inhomogeneous distribution phenomenon of illumination level was inevitably occurred in indoor farm racks generally. For accurately evaluating the productivity of choy sum grown on such racks, a light-time-biomass response model of choy sum seedling grown at the seedling stage was thus established for the first time, which could reliably predict the production outcome of this species in indoor farming practice under various lighting condition and duration. The robustness of the model was further tested by model variation test and sufficient robustness of this model was confirmed. The new insight obtained for the light-dependence of choy sum growth and the light-time-biomass response model can be used to efficiently direct its seedling production in indoor plant factories.
RESUMEN
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.
Asunto(s)
Brassica rapa , Carotenoides , Clorofila , Glucosinolatos , Hojas de la Planta , VerdurasRESUMEN
The ability of nine commercial broths to enrich healthy and 90% sanitizer-injured Salmonella Typhimurium and Salmonella cocktail on mung bean sprouts was evaluated to select an optimum broth for detection. Results showed that S. Typhimurium multiplied faster and reached a higher population in buffered peptone water (BPW), Salmonella AD media (AD) and ONE broth-Salmonella (OB), compared with other broths. Healthy and 90% sanitizer-injured Salmonella at low concentrations increased by 4.0 log CFU/ml in these three broths. However, no Salmonella growth was observed in lactose broth (LB). Further investigation showed that during incubation, pH of LB dropped from 6.7 to 4.2, due to production of lactic (66 mM) and acetic acids (62 mM) by lactic acid bacteria that were identified as dominant microbiota in bean sprouts. Though no cell membrane damage was detected by propidium monoazide combined with real-time PCR, it was found that LB inhibited Salmonella growth, especially from low inoculum levels. This study suggests that in consideration of effectiveness and cost, BPW would be a suitable enrichment broth to use for isolating and detecting Salmonella on mung bean sprouts, while using LB might cause false negative results in Salmonella detection by either PCR or standard cultural method.