Effect of Ratios of Red and White Light on the Growth and Quality of Pak Choi

Abstract

The effects of different ratios of red:white light on the biomass, photosynthetic capacity, phytochemical accumulation, and antioxidant capacity of pak choi were investigated. There were three treatments: red:white = 1:2 (LR), red:white = 1:1 (MR), red:white = 2:1 (HR) with white light as control (CK) at photosynthetic photon flux density (PPFD) of 250 μmol·m−2·s−1. In LR treatment, chlorophyll fluorescence and nitrate content were reduced, while the photosynthetic rate (Y(ll)), the contents of soluble protein, soluble sugar, vitamin C, flavonoids, polyphenols, glucosinolates, FRAP, and 2,2-diphenyl-1-bitter acyl radical scavenging increased. The chlorophyll content was enhanced in MR treatment, and the photosynthetic rate and glucosinolate content increased in HR treatment. The most suitable light for the cultivation of pak choi in the plant factory was red:white = 1:2.

Effects of Supplemental Red and Far-Red Light at Different Growth Stages on the Growth and Nutritional Properties of Lettuce

“…The preharvest supplementation of R light significantly enhanced the phenolic compounds and free radical scavenging activity in lettuce [44]. With the increase in the red light intensity, the antioxidant content and activity of pak choi enhanced [45]. The supplementation of R light for 10 days before harvest (A and FRR) increased the TPs content and DPPH in lettuce (Figure 5).…”

Effect of Red and Blue Light on the Growth and Antioxidant Activity of Alfalfa Sprouts

“…Soluble protein content was determined using Coomassie brilliant blue G-250 reagent [27]. We weighed 1.0 g of alfalfa sprouts, ground them and added 10 mL of distilled water for extraction, and centrifuged it at 4000 r/min for 20 min at 4 • C. We filtered it with a 0.22 µm filter head, aspirated 1 mL of supernatant, added 5 mL of Coomassie Brilliant Blue G-250, and mixed it and let it stand for 2 min, and absorbance values were measured at 595 nm (0-100 mg•L −1 BSA as a standard solution for soluble proteins).…”

“…Nitrate content was determined by a colorimetric method using salicylic acid [27]. We weighed 1.0 g of alfalfa sprouts into a 20 mL graduated test tube, added 10 mL of deionized water, placed it into a boiling water bath for 30 min, cooled and filtered it, and then condensed it into a 25 mL volumetric flask.…”

“…Zhou et al showed that mixed red and blue light was more effective than monochromatic red light in reducing nitrate content of lettuce, and the effect was more obvious in the R/B = 4 treatment [38]. He et al showed that red/white light = 2:1 can reduce the content of nitrate in cabbage leaves, and the increase in the proportion of red light nitrate reduction effect is not obvious [27]. Similar to the results of previous studies, the results of this experiment showed that red and blue compound color light could reduce the nitrate content of sprouts to a certain extent.…”

Rancang Bangun Sistem Plant Factory untuk Produksi Tanaman Pakcoy (Brassica rapa L.)

“…Adapun hasil pengujian suhu selama proses pertumbuhan dapat ditunjukkan pada Tabel 2. 29,9 -30,3 27,3 -28,2 28,8 -29,3 28,3 -29,1 20,9 -21,5 27,2 -28,9 27,5 -28,1 27,9 -29,5 27,3 -28,2 28,8 -30,2 27,9 -29,5 27,2 -28,7 27,4 -28,4 28,5 -29,5 27,2 -28,7 21,5 -22,5 29,5 -30 Tinggi tanaman pakcoy pada umur 7 HST yang ditanam pada Plant Factory ini mempunyai pertumbuhan yang lebih baik dibandingkan tinggi tanaman pada fase pembibitan dengan umur 14 HSS yang ditanam dibawah intensitas cahaya yang besar seperti 250 µmol/m 2 /s (He et al, 2022) dan 400 µmol/m 2 /s (Huang et al, 2021). Hal ini menunjukkan tingkat efisiensi panas yang terdapat pada plant factory yang digunakan lebih baik dibandingkan penelitian sejenis sebelumnya.…”