Table 2.
Forty six metabolites in leaves of bermudagrass under cold stress.
| Metabolites | Treatment | |||||
|---|---|---|---|---|---|---|
| NT | NT+MLT | NA | NA+MLT | CA | CA+MLT | |
| AMINO ACIDS | ||||||
| Glycine | 0.329 ± 0.007b | 0.327 ± 0.01c | 0.364 ± 0.01a | 0.422 ± 0.01a* | 0.284 ± 0.06c | 0.376 ± 0.01b* |
| Valine | 0.038 ± 0.007c | 0.037 ± 0.006c | 0.232 ± 0.02b | 0.081 ± 0.003b* | 0.276 ± 0.03a | 0.128 ± 0.02a* |
| Alanine | 0.286 ± 0.01a | 0.287 ± 0.01a | 0.078 ± 0.002c | 0.074 ± 0.004c | 0.086 ± 0.002b | 0.147 ± 0.005b* |
| Threonine | 0.05 ± 0.007b | 0.051 ± 0.01c | 0.065 ± 0.002a | 0.069 ± 0.001a* | 0.045 ± 0.003c | 0.115 ± 0.15b* |
| Proline | 0.37 ± 0.05c | 0.36 ± 0.08c | 1.566 ± 0.24a | 1.471 ± 0.29b | 1.517 ± 0.45a | 2.514 ± 0.48a* |
| Norvaline | 0.045 ± 0.003c | 0.046 ± 0.07c | 0.073 ± 0.01a | 0.071 ± 0.008b | 0.06 ± 0.005b | 0.081 ± 0.008a* |
| Serine | 0.027 ± 0.004b | 0.027 ± 0.01c | 0.43 ± 0.03a | 0.54 ± 0.03a* | 0.43 ± 0.02a | 0.5 ± 0.008b* |
| ORGANIC ACIDS | ||||||
| Propanoic acid | 0.262 ± 0.024b | 0.278 ± 0.018c | 0.473 ± 0.02a | 0.549 ± 0.01b* | 0.465 ± 0.01a | 0.868 ± 0.08a* |
| Phosphoric acid | 0.097 ± 0.029a | 0.112 ± 0.005a | 0.013 ± 0.0003c | 0.036 ± 0.002b* | 0.026 ± 0.002b | 0.034 ± 0.001b* |
| Acetic acid | 0.025 ± 0.001b | 0.025 ± 0.0004b | 0.024 ± 0.005b | 0.024 ± 0.006b | 0.033 ± 0.008a | 0.036 ± 0.004a* |
| Propenoic acid | 0.019 ± 0.001c | 0.019 ± 0.001c | 0.023 ± 0.003b | 0.03 ± 0.008b* | 0.038 ± 0.001a | 0.054 ± 0.006a* |
| Threonic acid | 0.02 ± 0.001b | 0.02 ± 0.002b | 0.28 ± 0.02a | 0.159 ± 0.02a* | 0.262 ± 0.03a | 0.162 ± 0.01a* |
| Glutamic acid | 0.114 ± 0.01c | 0.117 ± 0.02c | 0.42 ± 0.05b | 0.455 ± 0.007b | 1.89 ± 0.17a | 3.042 ± 0.16a* |
| Octadecanoic acid | – | – | 0.027 ± 0.002b | 0.025 ± 0.002b | 0.04 ± 0.002a | 0.137 ± 0.02a* |
| Aspartic acid | 0.08 ± 0.01a | 0.086 ± 0.004a | 0.036 ± 0.004c | 0.037 ± 0.002b | 0.059 ± 0.01b | 0.033 ± 0.005b* |
| Butanoic acid | 0.01 ± 0.001c | 0.01 ± 0.0003c | 0.33 ± 0.03b | 0.14 ± 0.04b* | 0.72 ± 0.01a | 0.83 ± 0.03a* |
| Butanedioic acid | 1.23 ± 0.07a | 1.22 ± 0.22a | 0.29 ± 0.11b | 0.03 ± 0.007c* | 0.21 ± 0.08bc | 0.25 ± 0.06b |
| Gluconic acid | 0.017 ± 0.001c | 0.018 ± 0.001c | 0.089 ± 0.06b | 0.08 ± 0.01b | 0.18 ± 0.14a | 0.2 ± 0.05a |
| Aconitic acid | – | – | 1.84 ± 0.54a | 0.92 ± 0.27b* | 1.08 ± 0.46b | 1.62 ± 0.44a* |
| Pentaric acid | 1.14 ± 0.09c | 1.08 ± 0.06c | 1.66 ± 0.35a | 1.35 ± 0.4b* | 1.44 ± 0.239b | 1.85 ± 0.15a* |
| Gluconic acid | – | – | 0.06 ± 0.01a | 0.02 ± 0.004b* | 0.03 ± 0.01b | 0.12 ± 0.009a* |
| Hexadecanoic acid | 0.06 ± 0.002b | 0.04 ± 0.0001b | 0.1 ± 0.06b | 0.05 ± 0.007b | 0.23 ± 0.04a | 0.27 ± 0.04a* |
| Propanedioic acid | 0.006 ± 0.0001c | 0.009 ± 0.0003c | 0.012 ± 0.005b | 0.017 ± 0.005b | 0.02 ± 0.006a | 0.05 ± 0.01a* |
| SUGARS | ||||||
| Arabinose | – | – | 0.108 ± 0.04b | 0.225 ± 0.04a* | 0.156 ± 0.04a | 0.214 ± 0.009a* |
| Fructose | 0.023 ± 0.003c | 0.023 ± 0.002c | 0.887 ± 0.05b | 1.483 ± 0.09b* | 2.671 ± 0.09a | 3.123 ± 0.09a* |
| Galactose | 0.056 ± 0.02c | 0.054 ± 0.01c | 0.172 ± 0.04b | 0.424 ± 0.07b* | 1.48 ± 0.25a | 6.1 ± 0.23a* |
| Glucose | 0.075 ± 0.007a | 0.079 ± 0.008b | 0.024 ± 0.002c | 0.03 ± 0.005c | 0.043 ± 0.003b | 0.091 ± 0.01a* |
| Glucopyranose | 0.029 ± 0.005c | 0.027 ± 0.002c | 0.079 ± 0.02a | 0.092 ± 0.007a* | 0.039 ± 0.002b | 0.05 ± 0.002b* |
| Sucrose | 5.549 ± 0.4c | 5.546 ± 0.5c | 6.009 ± 0.06b | 8.667 ± 0.4b* | 7.424 ± 0.4a | 14.44 ± 0.6a* |
| Maltose | 0.023 ± 0.003b | 0.026 ± 0.002c | 0.107 ± 0.01a | 0.175 ± 0.01a* | 0.099 ± 0.008a | 0.14 ± 0.002b* |
| Ribofuranose | 0.12 ± 0.01a | 0.12 ± 0.006a | 0.025 ± 0.005b | 0.02 ± 0.006b | 0.02 ± 0.005b | 0.019 ± 0.003b |
| Talopyranose | 0.03 ± 0.02b | 0.04 ± 0.002a | 0.07 ± 0.04a | 0.04 ± 0.01a* | 0.02 ± 0.01b | 0.01 ± 0.003b |
| Mannose | 0.19 ± 0.02c | 0.19 ± 0.01c | 0.31 ± 0.02b | 1.47 ± 0.5a* | 0.47 ± 0.1b | 0.55 ± 0.06b |
| Allose | 0.06 ± 0.09b | 0.06 ± 0.004c | 1.23 ± 0.14a | 0.55 ± 0.04a* | 0.03 ± 0.005c | 0.25 ± 0.08b |
| Allopyranose | 0.02 ± 0.009a | 0.027 ± 0.001a | 0.008 ± 0.004b | 0.009 ± 0.004b | 0.009 ± 0.003b | 0.01 ± 0.003b |
| Cellobiose | 0.019 ± 0.0006b | 0.014 ± 0.0004b | 0.023 ± 0.007b | 0.025 ± 0.01b | 0.082 ± 0.03a | 0.085 ± 0.01a |
| Turanose | – | – | 0.018 ± 0.003b | 0.12 ± 0.01a* | 0.04 ± 0.008a | 0.016 ± 0.001b* |
| Melibiose | – | – | 0.079 ± 0.02a | 0.081 ± 0.04a | – | – |
| Glucopyranoside | 0.16 ± 0.05a | 0.13 ± 0.002a | 0.18 ± 0.08a | 0.11 ± 0.03a | 0.14 ± 0.02a | 0.13 ± 0.06a |
| ALCOHOLS | ||||||
| Glycerol | 0.22 ± 0.02a | 0.23 ± 0.01a | 0.027 ± 0.004c | 0.042 ± 0.005c* | 0.075 ± 0.004b | 0.09 ± 0.002b* |
| Myo-Inositol | 0.27 ± 0.06b | 0.26 ± 0.02b | 0.476 ± 0.02a | 0.534 ± 0.05a* | 0.074 ± 0.003c | 0.252 ± 0.02c* |
| Mannitol | 0.14 ± 0.09a | 0.13 ± 0.1a | 0.11 ± 0.04b | 0.03 ± 0.01c* | 0.03 ± 0.01c | 0.057 ± 0.01b* |
| Galactinol | 0.4 ± 0.006b | 0.41 ± 0.08b | 0.61 ± 0.3a | 0.33 ± 0.09c* | 0.26 ± 0.09c | 0.55 ± 0.01a* |
| OTHERS (KETONE AND ALKANES) | ||||||
| Furanone | 0.015 ± 0.002c | 0.015 ± 0.001c | 0.091 ± 0.01b | 0.141 ± 0.02b* | 0.162 ± 0.01a | 0.436 ± 0.03a* |
| Pentasiloxane | 0.03 ± 0.01b | 0.025 ± 0.01b | 0.35 ± 0.05a | 0.14 ± 0.02a* | – | – |
| Silanol | 0.3 ± 0.02c | 0.37 ± 0.02c | 0.57 ± 0.01b | 0.56 ± 0.05b | 11.8 ± 0.2a | 12.4 ± 1.1a* |
NT was normal temperature of 30°C. CA was cold acclimation, which Bermudagrass were treated with 4°C for 7 d and then transferred to −5°C for 8 h. NA was cold stress without acclimation, which plants were treated with −5°C for 8 h without pre-treatment with 4°C. MLT was melatonin. Statistical analysis was performed by One-way analysis of variance (ANOVA). Means were separated with Duncan's multiple range tests at a significant level of P < 0.05. Different letters indicate statistical difference significance at P < 0.05 among the temperature treatments. Asterisk was significantly different after MLT treatment.