Table 2.
Summed results of effects of clipping, population origin (population) and altitude of population origin (altitude) on traits related to plant growth, tolerance to herbivory, production of phenolic compounds, effect of methanolic extracts and production of volatile organic compounds (VOCs). No interactions between clipping and population/altitude were significant (P > 0.05 in all cases) and the interactions are thus not shown (see File 3 in Supporting Information for details).
| Effect on | Effect of |
|||
|---|---|---|---|---|
| Clipping | Population | Altitude | ||
| Growth | ||||
| Growth: 3 months | No stems | NT | *** | +++ |
| No leaves on the longest stem | NT | *** | --- | |
| Length of the longest stem | NT | *** | --- | |
| Tolerance | ||||
| No leaves on the longest stem | +++ | n.s. | n.s. | |
| Length of the longest stem | +++ | *** | --- | |
| Shoot biomass | -- | * | -- | |
| Root biomass | -- | . | n.s. | |
| Root:shoot ratio | n.s. | *** | +++ | |
| Total biomass | n.s. | n.s. | n.s. | |
| Direct defences | ||||
| Phenolic compounds | Salicin | n.s. | *** | +++ |
| Rosmarinic acid | n.s. | * | – | |
| Esculin | n.s. | n.s. | n.s. | |
| Esculetin | n.s. | . | n.s. | |
| Methanolic extracts | LD50 | NT | n.s. | n.s. |
| LD90 | NT | n.s. | n.s. | |
| FDI50 | NT | n.s. | n.s. | |
| FDI90 | NT | n.s. | n.s. | |
| Indirect defences | ||||
| VOCs | Total VOCs production | +++ | n.s. | n.s. |
| (Z)-3-Hexen-1-yl acetate | +++ | n.s. | – | |
| (Z)-Linalool oxide (furanoid) | +++ | . | n.s. | |
| 1-Octen-3-yl acetate | +++ | . | n.s. | |
| (Z)-3-Hexenyl isovalerate | +++ | n.s. | .- | |
| Caryophyllene (E) | +++ | n.s. | .- | |
| Valencene | +++ | . | n.s. | |
| δ-Cadinene | +++ | n.s. | – | |
.P < 0.1.
P < 0.05.
P < 0.01.
P < 0.001, n.s. non-significant, NT = not tested.
LD50, LD90, FDI50 and FDI90 are the lethal doses (50 and 90%) and feeding deterrence index (50 and 90%) for third instar S. littoralis larvae.
‘+’ indicates positive effect of clipping/higher altitude (P < 0.05), i.e. clipped plants/plants from higher altitudes produce more stems, ‘ ++’ indicates positive effect of clipping/higher altitude (P < 0.01), ‘ +++’ indicates positive effect of clipping/higher altitude (P < 0.001).
‘-’ indicates negative effect of clipping/higher altitude (P < 0.05), i.e. clipped plants/plants from higher altitudes produce fewer stems, ‘--’ indicates negative effect of clipping/higher altitude (P < 0.01), ‘---’ indicates negative effect of clipping/higher altitude (P < 0.001).