Table 1.
Emission of volatile monoterpenes from undamaged (ctr) and Melolontha melolontha-damaged (herb) roots of Populus trichocarpa and P. nigra. Emission levels are displayed as means ± SE in pg g−1 h−1 fresh weight (n = 8). P-values are based on the results from Student’s t-tests or from Mann-Whitney Rank Sum Tests between control and herbivore treatments. MT: monoterpene, NA: not detected.
| P. trichocarpa | P. nigra | |||||||
|---|---|---|---|---|---|---|---|---|
| ctr | herb | P-value | t-value | ctr | herb | P-value | t-value/ T-value | |
| α-pinene | 83.9 ± 34.3 | 149.3 ± 77.1 | 0.765 | 0.305 | 25.8 ± 9.2 | 78.1 ± 40.9 | 0.677 | −0.426 |
| camphene | 52.6 ± 13.9 | 118.5 ± 31.6 | 0.061 | −2.042 | 38.2 ± 11.8 | 666.4 ± 233.6 | ≤ 0.001 | 37.00 |
| β-pinene | 108.5 ± 27.9 | 207.9 ± 48.5 | 0.085 | −1.854 | 31.3 ± 5.3 | 74.8 ± 21.9 | 0.058 | −2.065 |
| p-cymene | 108.7 ± 31.9 | 200.6 ± 84.1 | 0.458 | −0.764 | NA | NA | NA | NA |
| 1.8-cineole | 258.4 ± 47.2 | 577.3 ± 150.0 | 0.048 | 2.168 | 101.3 ± 20.3 | 117.5 ± 22.7 | 0.578 | −0.570 |
| unidentified MT1 | NA | NA | NA | NA | 0.0 ± 0.0 | 20.1 ± 8.0 | 0.038 | 48.00 |
| unidentified MT2 | NA | NA | NA | NA | 24.7 ± 3.6 | 30.5 ± 6.0 | 0.388 | −0.892 |
| unidentified MT3 | NA | NA | NA | NA | 82.9 ± 29.9 | 104.0 ± 33.9 | 0.625 | −0.5 |