| Popis: |
The contributions of multiple factors to plant defense and herbivory in different habitats has received limited study. This study examines the contributions of genotypic differentiation and modification by physical factors to chemical defense and herbivory of Myrica cerifera L. in contrasting habitats. The constitutive leaf monoterpene content of M. cerifera was higher in a sunny habitat than in an adjacent shady habitat at a southeastern USA coastal site. Leaf area loss was higher in the shady habitat than in the sunny habitat. A significant negative correlation of monoterpene content and leaf area loss suggests that monoterpenes may play toxic or deterrent roles in these plants. When plants from the two habitats were grown under uniform greenhouse conditions, the contents and compositions of leaf monoterpenes were not significantly different, implying that two ecotypes were not involved. The plants treated in high light intensity had significantly higher monoterpene content, higher growth rate, and denser glandular trichomes than the plants treated in low light intensity. Artificial wounding induced a significant increase of monoterpene production. However, the wounding responses of the plants from the two habitats were not different, nor did irradiance modify the response.Key words: ecotype, herbivory, light intensity, monoterpenes, wounding induction, Myrica cerifera. |
