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Figure 1.
The grape clusters of 'Jinling Xiangxin' during the ripening period under CPPU and TDZ treatments. Letters indicate different plant growth regulator treatments; specific concentrations are listed in Table 1.
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Figure 2.
Aroma radar map of 'Jinling Xiangxin' grapes with different treatments.
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Figure 3.
Expression trend analysis of 113 metabolites from CPPU and CPPU + TDZ treatments data sets.
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Figure 4.
Venn diagram depicting the shared and unique differentially expressed metabolites (DMs) identified by VIP and FC values across treatments.
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Figure 5.
Differential metabolites identified by VIP and FC values. (a) FC values for 5C–0C vs 5C–2.5C, 5C–0C vs 5C–5C. (b) FC values for 3C+2T–0C vs 3C+2T–2.5C, 3C+2T vs 5C–5C.
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Figure 6.
Aroma wheel of DMs in 5C–2.5C vs 5C–0C, 5C–5C vs 5C–0C, 3C+2T–2.5C vs 3C+2T–0C, and 3C+2T–5C vs 3C+2T–0C. Different colors represent treatment groups and correspond to the flavor characteristics and specific metabolites.
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Treatments 3 d post-bloom (DPB) 15 d post-bloom (DPB) 5C–0C 20 mg·L−1 GA3 + 5 mg·L−1 CPPU 25 mg·L−1 GA3 5C–2.5C 20 mg·L−1 GA3 + 5 mg·L−1 CPPU 25 mg·L−1 GA3 + 2.5 mg·L−1 CPPU 5C–5C 20 mg·L−1 GA3 + 5 mg·L−1 CPPU 25 mg·L−1 GA3 + 5 mg·L−1 CPPU 3C+2T–0C 20 mg·L−1 GA3 + 3 mg·L−1 CPPU + 2 mg·L−1 TDZ 25 mg·L−1 GA3 3C+2T–2.5C 20 mg·L−1 GA3 + 3 mg·L−1 CPPU + 2 mg·L−1 TDZ 25 mg·L−1 GA3 + 2.5 mg·L−1 CPPU 3C+2T–5C 20 mg·L−1 GA3 + 3 mg·L−1 CPPU + 2 mg·L−1 TDZ 25 mg·L−1 GA3 + 5 mg·L−1 CPPU Table 1.
Treatment of 'Jinling Xiangxin' clusters with CPPU and TDZ.
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Phenotypic characteristics 5C–0C 5C–2.5C 5C–5C 3C+2T–0C 3C+2T–2.5C 3C+2T–5C Longitudinal diameter (mm) 35.58 ± 2.55 bc 37.17 ± 1.57 a 37.55 ± 1.65 a 35.01 ± 1.27 c 35.77 ± 1.24 bc 36.15 ± 1.29 b Transverse diameter (mm) 24.81 ± 1.36 c 24.94 ± 0.91 bc 25.37 ± 1.06 bc 25.53 ± 1.28 b 27.26 ± 1.31 a 26.73 ± 1.02 a Berry shape index 1.44 ± 0.11 b 1.49 ± 0.08 a 1.48 ± 0.05 a 1.37 ± 0.07 c 1.31 ± 0.06 d 1.35 ± 0.05 c Single Berry weight (g) 11.23 ± 1.40 e 12.80 ± 1.10 cd 13.75 ± 1.21 b 12.48 ± 1.22 d 13.28 ± 1.12 bc 14.78 ± 0.99 a L 50.39 ± 0.42 a 49.60 ± 0.20 b 44.30 ± 0.30 f 47.88 ± 0.42 c 46.76 ± 0.54 d 45.47 ± 0.36 e a −6.80 ± 0.69 ab −7.28 ± 0.41 bc −6.50 ± 0.49 a −7.84 ± 0.83 c −7.46 ± 0.18 c −7.68 ± 0.26 c b 15.89 ± 0.44 a 14.47 ± 0.21 b 12.62 ± 0.52 c 15.31 ± 0.98 a 13.78 ± 0.66 b 13.89 ± 0.21 b C 25.57 ± 1.55 a 23.52 ± 0.50 b 21.31 ± 1.13 c 25.77 ± 2.11 a 23.18 ± 1.05 b 23.85 ± 0.92 b Note: Different letters within the same row mean significant differences according to a Duncan test (p < 0.05). The same below. Table 2.
Phenotypic characteristics of grape berries in CPPU and TDZ treatments.
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Fruit quality 5C–0C 5C–2.5C 5C-5C 3C+2T–0C 3C+2T–2.5C 3C+2T–5C Seedless ratio (%) 37.01 57.50 60.00 26.67 33.33 46.77 TSS (°Brix) 17.48 ± 0.15 b 16.95 ± 0.23 c 18.25 ± 0.18 a 16.35 ± 0.21 d 16.88 ± 0.19 c 17.68 ± 0.19 b TA 0.18 ± 0.01 d 0.27 ± 0.01 a 0.16 ± 0.01 e 0.21 ± 0.02 c 0.24 ± 0.01 b 0.19 ± 0.01 d TSS/TA 97.46 ± 6.53 b 63.70 ± 1.65 d 114.87 ± 6.88 a 77.04 ± 7.99 c 69.40 ± 3.57 cd 91.61 ± 3.39 b Soluble sugar (mg·g−1) 140.18 ± 2.38 bc 134.7 ± 3.20 c 154.09 ± 3.11 a 128.60 ± 2.93 d 136.04 ± 2.44 c 142.50 ± 4.07 b Soluble protein (mg·g−1) 0.25 ± 0.02 e 0.40 ± 0.04 bc 0.52 ± 0.05 a 0.31 ± 0.01 d 0.36 ± 0.02 c 0.44 ± 0.01 b Phenol (mg·g−1) 11.81 ± 0.33 c 11.16 ± 0.19 d 10.43 ± 0.31 e 13.14 ± 0.19 a 12.30 ± 0.28 b 11.71 ± 0.15 c Table 3.
The fruit quality of 'Jinling Xiangxin' grape in CPPU and CPPU + TDZ treatments.
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Index Principal component PC1 PC2 PC3 Longitudinal diameter 0.37 0.11 −0.78 Transverse diameter 0.08 −0.71 0.51 Single berry quality 0.52 −0.69 0.17 L −0.39 0.86 0.01 a 0.65 0.17 −0.20 b −0.82 0.51 0.01 C −0.79 0.41 0.19 TSS 0.77 0.50 0.12 TA −0.55 −0.55 −0.54 TSS/TA 0.70 0.55 0.39 Soluble protein content 0.84 0.37 0.11 Soluble sugar content 0.88 −0.30 −0.00 Total phenol content −0.77 −0.30 0.38 Variance contribution rate (%) 44.16 25.64 12.18 Cumulative variance contribution rate (%) 44.16 69.79 81.97 Table 4.
Score matrix, Eigenvalue and contribution ratio of principal components.
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Treatments F1 F2 F3 Comprehensive score Rank 5C−0C −0.80 2.17 0.25 0.54 2 5C−2.5C −0.76 −0.16 −1.10 0.24 6 5C−5C 4.14 −0.11 −0.01 0.68 1 3C+2T−0C −2.73 0.17 0.26 0.24 5 3C+2T−2.5C −0.82 −1.37 0.17 0.25 4 3C+2T−5C 0.96 −0.71 0.43 0.45 3 Table 5.
Comprehensive score and ranking of grape berry quality under different treatments.
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Compounds (μg/kg) 5C–0C 5C–2.5C 5C–5C 3C+2T–0C 3C+2T–2.5C 3C+2T–5C Alcohol 1-Dodecanol 26.09 ± 3.37ab 21.52 ± 0.79b 29.79 ± 2.77a 25.99 ± 3.53ab 29.94 ± 3.51a 25.02 ± 1.38ab 1-Heptanol 5.87 ± 0.60a 4.96 ± 0.60ab 5.33 ± 0.59ab 6.31 ± 1.37a 6.06 ± 1.14a 3.83 ± 0.42b 1-Octanol 0.98 ± 0.17ab 0.72 ± 0.09b 1.01 ± 0.11ab 0.98 ± 0.19ab 1.17 ± 0.19a 0.76 ± 0.10b (E)-2-Decenol 11.42 ± 0.90c 12.74 ± 0.19bc 15.84 ± 3.05a 14.43 ± 1.79ab 15.27 ± 0.78ab 13.37 ± 0.95abc Aldehyde (E)-2-Decenal 1.06 ± 0.10c 1.2 ± 0.20bc 2.02 ± 0.45a 1.13 ± 0.21bc 1.58 ± 0.32ab 0.98 ± 0.09c (E)-2-Heptenal 0.8 ± 0.24b 0.31 ± 0.02c 1.1 ± 0.18ab 0.94 ± 0.32ab 1.39 ± 0.13a 0.63 ± 0.45bc 2-Hexenal 31.12 ± 0.74a 34.12 ± 6.16a 33.08 ± 2.63a 29.63 ± 2.96a 32.71 ± 2.30a 22.45 ± 1.51b Veratraldehyde 9.82 ± 0.87a 7.46 ± 1.30b 12.02 ± 1.42a 9.97 ± 1.37a 12.02 ± 1.53a 10.06 ± 0.52a Tridecanal 4.25 ± 0.29bc 2.93 ± 0.78c 7.14 ± 2.97a 4.15 ± 1.00bc 6.56 ± 1.41ab 4.12 ± 0.24bc Ester Ethyl sorbate 2.91 ± 0.11bc 3.22 ± 0.06b 3.29 ± 0.5ab 2.7 ± 0.24c 3.74 ± 0.31a 2.45 ± 0.18c cis-3-Hexenyl butyrate 1.59 ± 0.34bc 1.43 ± 0.07c 2.13 ± 0.17a 1.52 ± 0.22c 1.98 ± 0.05ab 1.54 ± 0.33c Heptyl acetate 1.52 ± 0.42b 1.1 ± 0.16b 3.59 ± 1.12a 2.01 ± 0.73b 3.83 ± 1.38a 1.75 ± 0.47b 3-Mercaptohexyl acetate 1.21 ± 0.25bc 0.5 ± 0.08d 1.89 ± 0.53a 1.06 ± 0.42cd 1.74 ± 0.39ab 0.89 ± 0.09cd Ketone Apocynin 1.38 ± 0.12b 0.96 ± 0.08c 2.04 ± 0.37a 1.51 ± 0.18b 2 ± 0.14a 1.65 ± 0.09b Terpenoid Dihydro-β-ionol 0.52 ± 0.06ab 0.46 ± 0.09b 0.5 ± 0.09b 0.55 ± 0.03ab 0.46 ± 0.03b 0.63 ± 0.05a β-Bisabolene 1.11 ± 0.19bc 0.88 ± 0.07bc 1.53 ± 0.31a 0.8 ± 0.18c 1.23 ± 0.12ab 0.92 ± 0.17bc α-Pinene oxide 0.46 ± 0.17bc 0.88 ± 0.09a 0.41 ± 0.13bc 0.48 ± 0.09bc 0.31 ± 0.02c 0.58 ± 0.05b Note: Data are means (n = 3). The aroma compounds were listed on the left of the concentration arrays. Different superscript letters within a row indicate significant differences (p < 0.05). Table 6.
Concentrations (μg/kg) of volatile compounds determined in 'Jinling Xiangxin' grapes.
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Compounds (%) 5C–0C 5C–2.5C 5C–5C 3C+2T–0C 3C+2T–2.5C 3C+2T–5C Alcohol 10.33% 9.45% 11.72% 9.95% 10.98% 10.39% Aldehyde 21.31% 18.47% 20.24% 18.49% 21.66% 19.07% Ester 23.60% 26.35% 23.42% 25.73% 22.72% 23.00% Ketone 4.10% 3.70% 3.67% 3.96% 3.78% 5.01% Terpenoids 40.67% 42.04% 40.95% 41.87% 40.86% 42.53% Table 7.
Concentrations (%) of volatile compounds determined in 'Jinling Xiangxin' grapes.
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Compounds 5C–0C 5C–2.5C 5C–5C 3C+2T–0C 3C+2T–2.5C 3C+2T–5C Alcohol 1-Decanol 2.93 ± 0.23a 2.63 ± 0.20a 3.01 ± 0.59a 2.65 ± 0.11a 2.58 ± 0.34a 2.42 ± 0.22a 1-Heptanol* 19.58 ± 2.00a 21.05 ± 4.57a 16.52 ± 2.00ab 20.19 ± 3.78a 17.76 ± 1.97ab 12.75 ± 1.38b 1-Nonanol 107.85 ± 13.42a 104.69 ± 21.62a 94.55 ± 9.44a 111.29 ± 14.00a 126.24 ± 29.61a 95.34 ± 11.84a cis-3-Hexenol 6.8 ± 0.32a 7.36 ± 0.98a 7.45 ± 0.26a 7.38 ± 0.15a 8.35 ± 1.00a 7.3 ± 0.10a Aldehyde (E)-2-Decenal* 2.12 ± 0.21c 2.27 ± 0.42bc 2.41 ± 0.39bc 3.17 ± 0.63ab 4.03 ± 0.90a 1.96 ± 0.17c (E)-2-Heptenal < 1 < 1 < 1 1.07 ± 0.10 < 1 < 1 (Z,Z)-3,6-Nonadienal 6,958.62 ± 1,584.57a 5,172.79 ± 1,046.83a 5,731.27 ± 1,779.45a 5,586.22 ± 1,550.26a 5,522.15 ± 466.04a 4,696.66 ± 78a (Z)-2-Decenal 1.94 ± 0.19a 1.93 ± 0.39a 1.77 ± 0.05a 2.19 ± 0.22a 2.02 ± 0.14a 1.74 ± 0.10a (E)-2-Dodecenal 1.2 ± 0.33a 1.21 ± 0.17a 1.56 ± 0.51a < 1 1.15 ± 0.73a 1.33 ± 0.62a 2-Hexenal* 18.3 ± 0.44a 17.43 ± 1.74a 20.07 ± 3.62a 19.24 ± 1.35a 19.46 ± 1.55a 13.21 ± 0.89b 2-Nonenal 3,318.74 ± 415.65a 3,364.87 ± 579.68a 2,994.82 ± 229.00a 3,072.69 ± 269.00a 3,871.55 ± 1,195.27a 3,093.93 ± 305.02a (E)-4-Nonenal 34.43 ± 7.94a 25.3 ± 6.69a 26.76 ± 7.17a 28.31 ± 9.52a 26.27 ± 4.27a 25.34 ± 5.47a (Z)-6-Nonenal 9,059.03 ± 1,363.81a 7,871.97 ± 1,895.74a 7,654.85 ± 1,617.99a 8,510.44 ± 2,850.93a 7,726.05 ± 472.40a 6,940.68 ± 1183.23a Decanal 163.13 ± 12.82a 167.42 ± 13.94a 170.55 ± 27.07a 173.72 ± 5.50a 172.02 ± 16.18a 158.27 ± 13.89a Hexanal 52.06 ± 9.69a 46.86 ± 1.88a 51.42 ± 17.45a 52.64 ± 4.71a 43.98 ± 4.84a 35.59 ± 4.18a Nonanal 388.65 ± 26.36a 396.84 ± 46.30a 369.43 ± 33.52a 437.3 ± 67.22a 464.32 ± 82.78a 360.56 ± 14.38a Tridecanal < 1 < 1 < 1 < 1 1.02 ± 0.42 < 1 Ester Ethyl (2E,4Z)-decadienoate 5.03 ± 0.80a 4.55 ± 0.64a 4.35 ± 0.14a 5.4 ± 0.72a 5.41 ± 0.62a 4.56 ± 0.26a γ-Octalactone 9.61 ± 0.71a 9.53 ± 1.47a 9.63 ± 1.84a 8.85 ± 0.47a 9.27 ± 1.98a 8.96 ± 2.01a γ-Decalactone 132.2 ± 12.20a 134.83 ± 12.53a 136.24 ± 37.37a 141.39 ± 14.55a 133.82 ± 32.17a 137.19 ± 18.15a Methyl benzoate 189.24 ± 87.67a 102.67 ± 55.96a 147.76 ± 90.77a 123.05 ± 75.08a 103.97 ± 20.04a 90.75 ± 41.03a Hexyl propionate 11.1 ± 0.77a 11.76 ± 1.18a 10.55 ± 0.12a 10.18 ± 1.07a 13.52 ± 2.33a 12.55 ± 2.66a 2-Methylbutyl isobutyrate 4.96 ± 0.10a 6.49 ± 0.73a 6.73 ± 0.37a 6.41 ± 0.27a 6.34 ± 0.27a 5.39 ± 1.65a 2-Methylbutyl hexanoate 1.75 ± 0.20a 1.57 ± 0.23a 1.57 ± 0.05a 1.71 ± 0.18a 2.31 ± 0.63a 1.69 ± 0.36a Phenylethyl isovalerate 4,939.68 ± 751.48a 4,475.38 ± 645.28a 4,334.68 ± 114.62 5,175.7 ± 630.70a 5,205.61 ± 575.74a 4,447.44 ± 262.49a Methyl caprate 10.11 ± 2.51a 10.18 ± 4.25a 11.15 ± 2.30a 18.48 ± 16.32a 10.1 ± 3.05a 10.89 ± 3.25a Butyl butyrate 1.04 ± 0.04ca < 1 1.15 ± 0.02ba 1.34 ± 0.11aa 1.17 ± 0.18aba < 1 Ethyl heptanoate 4.08 ± 0.3a 3.85 ± 0.51a 4.15 ± 0.34a 4.31 ± 0.51a 4.62 ± 0.78a 4.24 ± 0.75a 3-Mercaptohexyl acetate 173.3 ± 21.39a 168.53 ± 24.47a 177.21 ± 31.24a 401.06 ± 315.41a 188.57 ± 18.67a 163.65 ± 20.67a Ketone (E,E)-3,5-Octadien-2-one 1,217.65 ± 231.00a 948.28 ± 121.36a 1,068.41 ± 188.01a 1,055.86 ± 270.81a 933.75 ± 45.11a 979.68 ± 138.92a 4-Undecanone 2.68 ± 1.47a 2.15 ± 0.25a 1.85 ± 0.28a 1.59 ± 0.07a 1.62 ± 0.20a 1.99 ± 0.16a Terpenoids Safranal 257.18 ± 30.49a 238.55 ± 35.69a 216.35 ± 7.70a 268.58 ± 25.92a 273.98 ± 26.46a 225.19 ± 22.38a β-Ionone epoxide 1.16 ± 0.19a 0.94 ± 0.13a 1.14 ± 0.08a 1.06 ± 0.12a 1.11 ± 0.11a < 1 L(−)-Borneol 12.98 ± 4.48a 19.38 ± 3.62a 16.88 ± 2.76a 17.59 ± 1.00a 19.06 ± 3.81a 17.16 ± 1.45a Carvone 2.02 ± 0.20a 1.91 ± 0.28a 1.98 ± 0.04a 2.01 ± 0.18a 2.18 ± 0.29a 1.83 ± 0.05a Isoterpinene 6.83 ± 3.23a 3.57 ± 2.08a 5.07 ± 3.43a 4.34 ± 2.98a 3.6 ± 0.73a 3.19 ± 1.47a Linalool 92.65 ± 40.99a 54.6 ± 20.82a 66.22 ± 45.06a 62.79 ± 40.79a 53.37 ± 6.86a 45.25 ± 17.49a δ-Cadinene 3.76 ± 1.60a 4.03 ± 4.40a 6.3 ± 3.52a 5.4 ± 3.08a 4.79 ± 3.36a 3.33 ± 2.22a Endo-Borneol 3.46 ± 1.19a 5.17 ± 0.96a 4.5 ± 0.74a 4.69 ± 0.27a 5.08 ± 1.02a 4.58 ± 0.39a Note: compounds with rOAV values less than 1 are not shown in the table. * Represents compounds with significant differences (p < 0.05). Table 8.
Relative odor activity values (rOAVs) of active volatile compounds.
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Compounds (%) 5C–0C 5C–2.5C 5C–5C 3C+2T–0C 5C–5C 3C+2T–5C Alcohol 0.50% 0.58% 0.52% 0.56% 0.62% 0.54% Aldehyde 73.47% 72.90% 72.81% 70.55% 71.43% 70.90% Ester 20.14% 21.05% 20.72% 23.26% 22.75% 22.61% Ketone 4.48% 4.06% 4.58% 4.17% 3.74% 4.54% Terpenoids 1.40% 1.41% 1.37% 1.46% 1.46% 1.41% Table 9.
rOAVs (%) of volatile compounds determined in 'Jinling Xiangxin' grapes.
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Treatment 5C–0C 5C–2.5C 5C–5C 3C+2T–0C 3C+2T–2.5C 3C+2T–5C Comprehensive
score0.63 0.55 0.53 0.36 0.58 0.10 Order 1 3 4 5 2 6 Table 10.
Membership function values of flavor in grapes with different treatments.
Figures
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Tables
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