Effects of artificial light quality on health-promoting compounds in broccoli sprouts

Effect of Se treatment on glucosinolate metabolism and health-promoting compounds in the broccoli sprouts of three cultivars

Effect of sucrose and mannitol on the accumulation of health-promoting compounds and the activity of metabolic enzymes in broccoli sprouts

Effects of light quality on plant development and fruit metabolism and their regulation by plant growth regulators in tomato

Broccoli sprouts are rich in health-promoting bioactive compounds. Their content depends on both cultivation light quality and temperature. However, these effects have been previously addressed in isolation. Here, the dual inputs of cultivation light quality [blue (B), red (R), mixture of R and B (R+B), mixture of R and UVA (R+UVA)] and air temperature (15, 19, and 23 °C) on determining growth, external quality, and the cotyledon and hypocotyl content of five major bioactive compounds were investigated. The carbohydrate status at harvest and postharvest ratio of variable to maximum fluorescence (Fv/Fm) were also assessed. Hypocotyl length was generally enhanced under monochromatic light (R or B) and elevated temperature. Total phenolic, total flavonoid, and glucoraphanin contents were generally higher in cotyledon as compared to hypocotyl. Hypocotyl anthocyanin, total phenolic, total flavonoid, and ascorbic acid contents were generally enhanced by R+B, and were decreased by R. Cotyledon content in these metabolites was generally stimulated by B, and reduced under R or R+UVA. Temperature affected metabolite content depending on the metabolite, organ, and light quality. Lower temperatures, R (23 °C) or R+UVA (15, 19, and 23 °C) were associated with decreased postharvest Fv/Fm. In conclusion, low cultivation temperature (<23 °C), as well as R or R+UVA ought to be avoided. Instead, B and R+B are suitable, with B being preferable, owing to better external quality and enhanced metabolite content in cotyledon which generally holds higher content than hypocotyl.

Seedlin g quality is directly related to the success rate of automatic grafting. To select the suitable light quality for cultivating mechanically grafted tomato seedlings, the effects of different LED light qualities on the morphological parameters and mechanical properties of tomato seedlings were measured in an artificial light environment in a plant factory. Combination of red (R) and blue (B) LEDs as follows: R: B=100:0 (RLT), R: B=75:25(RBI), R: B=50:50(RBII), R: B=25:75(RBIII), R: B=0:100(BLT). The results showed that Red light is beneficial for the elongation of the hypocotyl of seedlings, Blue light is beneficial for the accumulation of dry matter in seedlings and monochromatic red light can reduce the seedling index. The effect of light quality on rootstocks and scions is different. Increasing the proportion of blue light is beneficial for increasing the stem diameter of scions, but it is not significant for the stem diameter of rootstocks. On the 25th to 30th day, the growth rate of stem diameter is the fastest. Based on morphological characteristics, the suitable light quality for rootstocks is RBI and RBII, and scions are RBII and RBIII. The mechanical properties of rootstocks and scions under different light-quality treatments were measured, and the results showed that the mechanical properties of scions were generally better than those of rootstocks. The rootstock has a significantly better bending strength than the scion, while the scion has a significantly better radial and axial compression force than the rootstock. Considering the automatic grafting process and mechanical characteristics, BLT and RBII were selected as the suitable light quality for rootstocks and scions. Based on the influence of comprehensive light quality on morphological and mechanical characteristics, the suitable light quality for cultivating mechanically grafted tomato seedlings is RBII.

Health-promoting compounds, antioxidant and myrosinase activity in the sprouts of three broccoli cultivars under 40 mM, 80 mM and 160 mM NaCl were investigated. LangYan (LY) sprouts had the richest health-promoting compounds among the evaluated cultivars. Treatment of 40 mM and 80 mM NaCl significantly decreased the content of ascorbic acid and total phenolic as well as antioxidant activity, but did not affect glucoraphanin, sulforaphane and myrosinase activity compared to the control. However, 160 mM NaCl treatment significantly enhanced the level of total phenolic, glucoraphanin, sulforaphane, antioxidant and myrosinase activity, while significantly decreased ascorbic acid content. The results suggest that 160 mM NaCl treatment would enhance antioxidant activity and sulforaphane yield in broccoli sprouts. The health-promoting value of broccoli sprouts depends on plant genotype and could be affected by NaCl stress.

The effect of light quality, light intensity and photoperiod on stem elongation of chrysanthemum was studied using an image processing technique. The plant stem and internode elongation was higher in the dark than in the light, and the growth of chrysanthemum was promoted in dark period. The effect of light quality was more significant than that of light intensity and photoperiod on the growth of chrysanthemum. The growth of chrysanthemum was inhibited under blue light, and the relative elongation rate of internodes decreased with increasing intensity of blue light and irradiation duration. Chrysanthemum growth is regulated by the light condition during irradiation. This system is useful to build a model to describe the stem elongation relative to light condition for chrysanthemum, and to suggest effective production method with substitutes for chemical growth regulators.

The effect of photoperiod and light quality on Macrolophus pygmaeus Rambur (Hemiptera: Miridae) nymphal development, fecundity and longevity

Effects of light quality on main health-promoting compounds and antioxidant capacity of Chinese kale sprouts

Effect of 2, 4-epibrassinolide on main health-promoting compounds in broccoli sprouts

Effects of combined treatment of light quality and melatonin on health-promoting compounds in Chinese kale sprouts

The effect of light quality on growth, photosynthesis, leaf anatomy and volatile isoprenoids of a monoterpene-emitting herbaceous species (Solanum lycopersicum L.) and an isoprene-emitting tree (Platanus orientalis L.)

Metabolomic analysis based on EESI-MS indicate blue LED light promotes aliphatic-glucosinolates biosynthesis in broccoli sprouts

We investigated the mechanism of the effect of different light qualities on the synthesis and regulation of mung bean sprouts. Light quality acts as a signal molecule, strongly enhancing polyphenol biosynthesis in sprouts. Mung bean (Vigna radiata) sprouts are a popular sprouting vegetable all over the world and are an excellent source of polyphenols with high antioxidant activity. This study investigated the effects of light qualities on the kinetic changes and metabolic regulation mechanism of light signal-mediating polyphenols in three mung bean sprout cultivars. Experimental results showed that three light qualities significantly enhanced the contents of caffeic acid, rutin, vitexin,genistin and delphinidin 3-glucoside. Interestingly, ferulic acid and vitexin responded selectively to blue light and red light, severally. Most genes involved in polyphenol biosynthesis were activated under different light quality conditions, resulting in an overaccumulation of phenylpropanoids. Pearson correlation analysis showed that PAL, F3H, F3'H and F3'5'H expression correlated highly with rutin, whereas ANS expression paralleled anthocyanin biosynthesis. Moreover, MYB111, MYB3, MYB4, MYB1 and MYC2 were critical regulators of polyphenol biosynthesis in mung bean sprouts. These changes were likely due to the changes in theexpression of the photoreceptor genes CRY-D, PHOT2, PHYE and light response genes (PIF3 and HY5). Our results provide insights into polyphenol biosynthesis in sprouts and microgreens.

Selenium (Se) supplement was combined with different LED light qualities to investigate mutual effects on the growth, nutritional quality, contents of glucosinolates and mineral elements in broccoli sprouts. There were five treatments: CK:1R1B1G, 1R1B1G+Se (100 μmol L−1 Na2SeO3), 1R1B+Se, 1R2B+Se, 2R1B+Se, 60 μmol m−2 s−1 PPFD, 12 h/12 h (light/dark). Sprouts under a combination of selenium and LED light quality treatment exhibited no remarkable change fresh weight, but had a shorter hypocotyl length, lower moisture content and heavier dry weight, especially with 1R2B+Se treatment. The contents of carotenoid, soluble protein, soluble sugar, vitamin C, total flavonoids, total polyphenol and contents of total glucosinolates and organic Se were dramatically improved through the combination of Se and LED light quality. Moreover, heat map and principal component analysis showed that broccoli sprouts under 1R2B+Se treatment had higher nutritional quality and health-promoting compound contents than other treatments. This suggests that the Se supplement under suitable LED lights might be beneficial to selenium-biofortified broccoli sprout production.