Table 4. Regression analyses of the dose-response effects of six VOCs on the germination and early growth of Digitaria sanguinalis.
| Regression equation | r2adj | IC 50 (ppm) | IC 80 (ppm) | ||
|---|---|---|---|---|---|
| Linalool | Germination | y = -3.294x + 106.8 | 0.888 | 17.25 | 26.35 |
| Root length | y = 0.122x2–6.633x + 100.3 | 0.999 | 9.11 | 18.20 | |
| Shoot length | y = 0.210x2–8.791x + 95.02 | 0.952 | 5.97 | 11.94 | |
| Root biomass | y = -3.495x + 94.49 | 0.965 | 12.73 | 21.31 | |
| Shoot biomass | y = 0.194x2–8.331x + 93.95 | 0.925 | 6.16 | 12.54 | |
| Terpinen-4-ol | Germination | y = 0.086x2–3.748x + 98.71 | 0.796 | o.r. | o.r. |
| Root length | y = -3.088x + 104.5 | 0.935 | 17.65 | 27.36 | |
| Shoot length | y = -3.424x + 95.40 | 0.935 | 13.26 | 22.02 | |
| Root biomass | y = -0.090x2–0.788x + 105.7 | 0.884 | 20.88 | 26.79 | |
| Shoot biomass | y = -3.264x + 92.69 | 0.928 | 13.08 | 22.27 | |
| α-Terpineol | Germination | y = 0.150x2–7.436x + 101.6 | 0.987 | 8.34 | 16.40 |
| Root length | y = 0.128x2–5.713x + 102.2 | 0.931 | 12.82 | o.r. | |
| Shoot length | y = 0.098x2–5.948x + 100.3 | 0.996 | 10.16 | 20.27 | |
| Root biomass | y = 0.110x2–5.613x + 103.4 | 0.951 | 12.65 | o.r. | |
| Shoot biomass | y = 0.093x2–5.769x + 100.6 | 0.996 | 10.57 | 21.25 | |
| Verbenone | Germination | y = -2.126x + 92.09 | 0.715 | 19.80 | 33.90 |
| Root length | y = 0.157x2–7.079x + 100.7 | 0.976 | 8.93 | o.r. | |
| Shoot length | y = 0.196x2–8.447x + 97.98 | 0.977 | 6.73 | 13.39 | |
| Root biomass | y = 0.104x2–5.830x + 103.3 | 0.957 | 11.50 | o.r. | |
| Shoot biomass | y = 0.185x2–8.192x + 96.93 | 0.968 | 6.76 | 13.52 | |
| Eugenol | Germination | y = -0.101x2–0.705x + 99.09 | 0.993 | 18.83 | 24.71 |
| Root length | y = 0.239x2–8.824x + 93.25 | 0.887 | 5.82 | 12.60 | |
| Shoot length | y = 0.295x2–10.62x + 91.89 | 0.877 | 4.51 | 9.04 | |
| Root biomass | y = 0.212x2–8.186x + 97.39 | 0.979 | 7.09 | 16.53 | |
| Shoot biomass | y = 0.277x2–10.38x + 94.46 | 0.944 | 4.93 | 9.67 | |
| Theaspirane | Germination | y = 0.007x2–0.754x + 97.93 | 0.660 | o.r. | o.r. |
| Root length | y = -0.123x2 + 3.640x + 102.4 | 0.668 | 40.19 | 44.61 | |
| Shoot length | y = 0.123x2–5.415x + 97.92 | 0.977 | 12.27 | o.r. | |
| Root biomass | y = -0.073x2 + 2.129x + 105.3 | 0.101 | 45.73 | 51.75 | |
| Shoot biomass | y = 0.116x2–5.231x + 98.71 | 0.980 | 13.14 | o.r. |
r2 adj = adjusted coefficient of determination
IC50 = concentration that inhibits or reduces germination and growth at 50% of control
IC80 = concentration that inhibits or reduces germination and growth at 80% of control
o.r. = out of range
IC values calculated from equation overcoming the maximum assayed concentration are expressed in italics