Table 1.
Reversibility of the phytotoxic effects on the germination of two agricultural weeds species pre-treated with pairs of volatile compounds and then transferred to water in the absence of volatile organic compounds (VOCs). Data are expressed as percentages relative to the control ± standard deviation (SD). For each weed species, p-values of the effects of pairs were significant at p ≤ 0.05, very significant at p ≤ 0.01, highly significant at p ≤ 0.001, and not significant at p ≤ 0.05 (determined by ANOVA or independent sample t-tests). For each weed species and pair, mean values labeled with distinct letters were significantly different at p ≤ 0.05 (Fisher’s Least Significant Difference test, LSD) for post hoc multiple comparisons). Percentages indicate the increasing participation of the first compound in the mixture, i.e., 0, 3.1, 6.25, 9.4, and 12.5 ppm in the assayed volume.
| Pair | Pre-Treatment Participation of the First Compound (%) | Germination (% ± SD) | |||||
|---|---|---|---|---|---|---|---|
| Amaranthus retroflexus | p-value | Digitaria sanguinalis | p-value | ||||
| Eugenol/verbenone | 0 | 10.0 ± 8.17 | b | 0.022 | 25.0 ± 19.1 | a | 0.412 |
| 25 | 45.0 ± 10.0 | a | 45.0 ± 34.2 | a | |||
| 50 | 50.0 ± 25.8 | a | 20.0 ± 16.3 | a | |||
| 75 | 40.0 ± 16.3 | a | 35.0 ± 10.0 | a | |||
| 100 | # | # | |||||
| Eugenol/terpinen-4-ol | 0 | # | 0.493 | # | 0.064 | ||
| 25 | 55.0 ± 19.1 | 5.0 ± 10.0 | a | ||||
| 50 | 70.0 ± 34.6 | 30.0 ± 11.5 | a | ||||
| 75 | 50.0 ± 11.5 | 20.0 ± 16.3 | a | ||||
| 100 | # | # | |||||
| Eugenol/α-terpineol | 0 | 50.0 ± 20.0 | ab | 0.022 | 15.0 ± 10.0 | a | 0.538 |
| 25 | 30.0 ± 25.8 | b | 20.0 ± 16.3 | a | |||
| 50 | 80.0 ± 16.3 | a | 15.0 ± 19.1 | a | |||
| 75 | 40.0 ± 16.3 | b | 5.0 ± 10.0 | a | |||
| 100 | # | # | |||||
| Eugenol/linalool | 0 | # | 0.704 | 13.2 ± 5.3 | a | 0.888 | |
| 25 | 80.0 ± 28.3 | a | 15.0 ± 10.0 | a | |||
| 50 | 60.0 ± 43.2 | a | 15.0 ± 19.1 | a | |||
| 75 | 75.0 ± 30.0 | a | 20.0 ± 16.3 | a | |||
| 100 | # | # | |||||
| Verbenone/α-terpineol | 0 | 50.0 ± 20.0 | a | 0.009 | 15.0 ± 10.0 | a | 0.749 |
| 25 | 50.0 ± 24.6 | a | 15.0 ± 10.0 | a | |||
| 50 | 50.0 ± 25.8 | a | 25.0 ± 25.2 | a | |||
| 75 | 20.0 ± 11.3 | b | 30.0 ± 25.8 | a | |||
| 100 | 10.0 ± 8.17 | b | 25.0 ± 19.1 | a | |||
| Verbenone/linalool | 0 | # | 0.023 | 13.2 ± 5.3 | a | 0.315 | |
| 25 | 55.0 ± 10.0 | a | 20.0 ± 16.3 | a | |||
| 50 | 40.0 ± 16.3 | ab | 25.0 ± 10.0 | a | |||
| 75 | 40.0 ± 28.3 | ab | 40.0 ± 28.3 | a | |||
| 100 | 10.0 ± 8.17 | b | 25.0 ± 19.1 | a | |||
| α-Terpineol/linalool | 0 | # | 0.714 | 13.2 ± 5.3 | a | 0.720 | |
| 25 | 45.0 ± 19.1 | a | 25.0 ± 10.0 | a | |||
| 50 | 65.0 ± 19.1 | a | 30.0 ± 11.5 | a | |||
| 75 | 50.0 ± 38.3 | a | 20.0 ± 40.0 | a | |||
| 100 | 50.0 ± 20.0 | a | 15.0 ± 10.0 | a | |||
| Verbenone/terpinen-4-ol | 0 | # | 0.039 | # | 0.227 | ||
| 25 | 25.0 ± 10.0 | b | 30.0 ± 25.8 | a | |||
| 50 | 45.0 ± 11.23 | a | 15.0 ± 10.0 | a | |||
| 75 | 55.0 ± 14.3 | a | 45.0 ± 19.1 | a | |||
| 100 | 10.0 ± 8.17 | b | 25.0 ± 19.1 | a | |||
| α-Terpineol/terpinen-4-ol | 0 | # | 0.292 | # | 0.726 | ||
| 25 | 50.0 ± 25.8 | a | 10.0 ± 11.5 | a | |||
| 50 | 70.0 ± 25.8 | a | 20.0 ± 16.3 | a | |||
| 75 | 35.0 ± 25.2 | a | 15.0 ± 10.0 | a | |||
| 100 | 50.0 ± 20.0 | a | 15.0 ± 10.0 | a | |||
| Terpinen-4-ol/linalool | 0 | # | 0.943 | 13.2 ± 5.3 | a | 0.906 | |
| 25 | 45.0 ± 19.1 | a | # | ||||
| 50 | 50.0 ± 25.8 | a | 15.0 ± 19.1 | a | |||
| 75 | 50.0 ± 25.8 | a | # | ||||
| 100 | # | # | |||||
# Concentrations for which the minimum number of ten non-germinated seeds for the reversibility bioassay was not achieved.