Figures (6)  Tables (0)

    • Figure 1. 

      Phenotypic and physiological characteristics of grapes under different light quality treatments. (a) Color phenotypes of 'Queen Nina' grapes at 15, 30 and 45 d after treatment with different light qualities. Abbreviations: W, white light treatment; R, red light treatment; B, blue light treatment; R1B1, red and blue light at a 1:1 ratio; R4B1, red and blue light at a 4:1 ratio; R1B4, red and blue light at a 1:4 ratio. (b)−(d) Measurement of various physiological parameters including individual berry weight, longitudinal and transverse diameters. (e) Color difference a*; (f) Color difference b*; (g) Color saturation c*. Data are presented as mean ± standard deviation (n = 10). Different letters indicate statistically significant differences based on one-way analysis of variance (P < 0.05).

    • Figure 2. 

      Changes of sugar and acid in grape berry after different light quality treatments at 15, 30, and 45 d. (a) Total soluble solids content (TSS); (b) Titratable acidity (TA); (c) Sugar acid ratio (TSS/TA); (d) Glucose content; (e) Fructose content; (f) Sucrose content; (g) Tartaric acid content; (h) L-malic acid content; (i) Citric acid content. Data are presented as mean ± standard deviation (n = 3). Different letters indicate statistically significant differences based on one-way analysis of variance (p < 0.05).

    • Figure 3. 

      Changes in grape berry anthocyanin components and color difference after different light quality treatments at 15, 30, and 45 d. (a) Total anthocyanin content (TAC); (b) Peonidin-3-O-glucoside content (Pn); (c) Cyanidin-3-O-glucoside content (Cy); (d) Petunidin-3-O-glucoside content (Pt); (e) Delphinidin-3-O-glucoside content (Dp); (f) Malvidin-3-O-glucoside content (Mv); (g)−(i) total chlorophyll content, chlorophyll a content, chlorophyll b content at each time point. Data are presented as mean ± standard deviation (n = 3). Different letters indicate statistically significant differences based on one-way analysis of variance (P < 0.05).

    • Figure 4. 

      Changes in grape berry flavonoid components after different light quality treatments at 45 d. (a) Total flavonoid content; (b) Flavanols content; PB1, procyanidin B1; PB2, procyanidin B2; EGCG, epigallocatechin gallate; (c) Flavonols content; Quercetin-gal, Quercetin-galctoside; Quercetin-glu, Quercetin-glucoside; Myricetin-gal, Myricetin-galctoside; Myricetin-glu, Myricetin-glucoside; Kaempferol-gal, Kaempferol-galctoside. (d) Isoflavones content; (e) Flavones content. Data are presented as mean ± standard deviation (n = 3). Different letters indicate statistically significant differences based on a one-way analysis of variance (p < 0.05).

    • Figure 5. 

      Changes in grape berry aroma components after different light quality treatments at 45 d. (a) Total aroma content; (b) Venn diagrams presenting unique and common aroma metabolites in six light treatments compared to control; (c) Aroma components up-regulated and down-regulated by six light treatments compared to control; (d) Heat maps of 107 VOCs components in all treatments.

    • Figure 6. 

      Correlation analysis of 19 quality indicators in 'Queen Nina'. (a) The color intensity and circle size are proportional to the value of each correlation coefficient. Red represents a positive correlation, and blue represents a negative correlation. TTA, tartaric acid; LMA, L-malic acid; CA, citric acid; Ant, total anthocyanins; HC, Heter compound. (b) PCA scores of physiological parameters of 'Queen Nina' under different treatments at maturity stage. (c) Radar plots of sensory assessment of different treatments at harvest.