Table 1.
Values of half-maximal effective concentration (EC50) calculated for germination of Orobanche cumana seeds exposed to increasing concentrations of (+)-GR24, (−)-epi-GR24, rac-GR24, and the halogenated (+)-GR24 analogs.
| Compounds | Concentration (M) | EC50 (10−8M) | ||||
|---|---|---|---|---|---|---|
| 1.0×10−9 | 1.0×10−8 | 2.0×10−8 | 1.0×10−7 | 1.0×10−6 | ||
| (+)-GR24 | 7.3±5.9%a | 21.5±13.4%c | 41.1±10.1%b | 66.6±9.1%c | 81.5±3.9%b | 5.1±1.32 |
| (−)-epi-GR24 | 0b | 0d | 0c | 0d | 0d | – |
| 7-bromo-GR24 | 16.9±4.1%a | 39.6±5.0%b | 49.1±6.6%b | 69.6±3.3%b | 83.8±2.5%b | 2.3±0.28 |
| 7-fluoro-GR24 | 11.2±7.8%a | 62.0±9.1%a | 63.8±4.9%a | 84.2±8.6%a | 90.9±3.8%a | 0.97±0.29 |
| rac-GR24 | 15.3±8.5%a | 27.2±4.2%c | 47.1±5.0%b | 58.5±10.7%c | 75.2±5.7%c | 5.3±1.44 |
Different lowercase letters in the same column indicate significant differences between means, according to the least significant difference test (p<0.05). Values represent means±SD (n=3).