Table 3.
Mean amount of volatile organic compounds (VOCs) (in ng; mean ± SE) emitted by potato plants under different treatments (i.e.,: INTACT plants = neither cis-jasmone nor aphid treatment; CJ = cis-jasmone treatment; ME = Macrosiphum euphorbiae–infested; CJME = cis-jasmone treatment then infestation afterwards with M. euphorbiae; SUR = surfactant treatment). Air entrainment was conducted for 120 hr in five periods of 24 hr. Data shown here are for the 24–48 hr and 72–96 hr VOC collection points. Results (P-values) of one-way ANOVA are given
| Compounds | Potato VOCs collected during 24–48 hr air entrainment | Potato VOCs collected during 72–96 hr air entrainment | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| INTACT | CJ | ME | CJME | SUR | P value | INTACT | CJ | ME | CJME | SUR | P value | ||
| 1 | (E)-2-Hexenal | n.d.c | 37.9 ± 1.9ab | 60.7 ± 9.3ab | 90.8 ± 30.8a | 6.7 ± 3.6 b | 0.026 | 3.1 ± 0.5b | 8.1 ± 0.9b | 176.3 ± 17.2a | 205.1 ± 93.3a | 5.2 ± 2.2b | 0.045 |
| 2 | α-Pinene | 7.8 ± 1.4 | 23.9 ± 5.1 | 27.3 ± 11.3 | 31.7 ± 8.8 | 19.7 ± 3.9 | 0.403 | 23.6 ± 2.8 | 39.17 ± 10.8 | 99.7 ± 37.2 | 129.3 ± 72.9 | 39.1 ± 16.7 | 0.460 |
| 3 | MHO | 12.9 ± 3.1 b | 19.1 ± 9.4 b | 174.8 ± 35.5a | 96.5 ± 30.9ab | 20.7 ± 3.6b | 0.006 | 15.9 ± 8.4c | 67.5 ± 16.9b | 249.9 ± 42.3a | 18.9 ± 9.1bc | 4.5 ± 1.5c | ˂0.001 |
| 4 | MeBA | 6.7 ± 3.2 | 12.6 ± 5.1 | 33.3 ± 3.9 | 18.9 ± 5.5 | 11.6 ± 5.7 | 0.069 | 28.9 ± 7.4c | 106.8 ± 33.8b | 134.4 ± 34.8b | 296.3 ± 75.5a | 60.3 ± 2.6bc | 0.026 |
| 5 | Nonanal | 37.7 ± 10.4 | 89.7 ± 19.1 | 148.8 ± 33.9 | 137.6 ± 36.1 | 122.9 ± 32.3 | 0.229 | 60.6 ± 16.3c | 94.5 ± 19.7b | 223.1 ± 29.2b | 238.5 ± 19.1a | 135.7 ± 33.3b | 0.006 |
| 6 | DMNT | 4.4 ± 1.9 b | 309.1 ± 38.9a | 439.8 ± 131.8a | 313.5 ± 90.7a | n.d. b | 0.019 | 33.3 ± 6.9b | 494.3 ± 50.1a | 414.7 ± 33.2a | 548.6 ± 92.2a | 25.1 ± 10.3b | ˂0.001 |
| 7 | (Z)-3-Hexen-1-yl butyrate | 4.9 ± 2.3 | 5.4 ± 1.7 | 77.4 ± 49.2 | 78.7 ± 27.8 | 15.4 ± 5.4 | 0.171 | 10.7 ± 6.2 | 5.5 ± 1.5 | 13.4 ± 6.8 | 29.5 ± 13.3 | 3.6 ± 1.7 | 0.757 |
| 8 | MeSA | 1.2 ± 0.9 | 5.1 ± 2.9 | 12.1 ± 5.9 | 41.2 ± 18.9 | n.d. | 0.302 | 11.6 ± 1.9c | 63.8 ± 14.7b | 90.3 ± 23.7ab | 154.3 ± 29.1a | 12.7 ± 3.5c | 0.005 |
| 9 | Decanal | 112.4 ± 29.7 | 75.9 ± 40.1 | 44.2 ± 21.3 | 142.3 ± 8.3 | 220.1 ± 53.9 | 0.103 | 129.7 ± 18.6a | 53.9 ± 15.9b | 44.3 ± 10.6b | 171.2 ± 23.8a | 49.6 ± 16.4b | 0.006 |
| 10 | Indole | 173.5 ± 55.6a | n.d.c | 57.3 ± 18.1 b | 41.9 ± 11.6 b | 34.2 ± 5.9 b | 0.038 | 62.5 ± 6.2 | 145.5 ± 26.3 | 129.6 ± 24.1 | 91.5 ± 42.5 | 36.1 ± 14.8 | 0.161 |
| 11 | cis-Jasmone | n.d.c | 26.6 ± 3.4b | 48.5 ± 16.6b | 138.9 ± 26.1a | n.d.c | 0.013 | 4.7 ± 1.7c | 15.9 ± 5.6c | 70.3 ± 16.1b | 200.3 ± 8.3a | 6.1 ± 0.9c | ˂0.001 |
| 12 | α-Copaene | 175.7 ± 78.7 | 5.7 ± 1.9 | 46.5 ± 17.6 | 28.1 ± 11.9 | 18.9 ± 7.5 | 0.062 | 118.9 ± 15.4a | 78.51 ± 26.7a | 22.7 ± 6.8b | 89.9 ± 26.1a | 4.7 ± 1.9b | 0.024 |
| 13 | (E)-β-Farnesene | n.d.c | 18.3 ± 2.2ab | 23.1 ± 5.9a | 15.9 ± 4.7a | 4.9 ± 2.1bc | 0.022 | 2.7 ± 1.2c | 16.7 ± 0.8b | 8.3 ± 5.5bc | 37.8 ± 9.4a | 3.1 ± 1.5c | 0.011 |
| 14 | TMTT | n.d.b | 593.1 ± 189.1a | 585.3 ± 176.9a | 1035.3 ± 171.3a | n.d.b | 0.007 | 18.9 ± 2.9b | 541.7 ± 121.7a | 714.8 ± 72.5a | 1023.5 ± 262.1a | n.d.b | 0.005 |
The compounds are ordered in accordance with their increasing GC retention time. Different letters indicate significant differences between treatments (P < 0.05, Student-Newman-Keuls method) when the one-way ANOVA result was significant (P < 0.05, F-test). For aphid infested plants (ME or CJME), potato plants were challenged with 100 apterous individuals of M. euphorbiae
P-values in bold indicate significant differences between treatments (P < 0.05)