PARENT SESSION
Poster Session 2: Forest Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Altitudinal distribution patterns of lianas: Relationships with their vascular anatomy and freeze embolism.
Jimenez-Castillo, Mylthon1, Lusk, Chris1, 1 Laboratorio de Ecologia Forestal, Departamento Botanica, Universidad de Concepcion., Concepción, Chile
ABSTRACT- Although lianas develop thinner stems than trees, they have wider vessels and can develop greater specific hydraulic conductivity. Because wide vessels are more vulnerable to freeze embolism, this anatomical characteristic could be a disadvantage in cold environments, explaining why lianas are not very abundant in temperate forests. In this study, we examine how liana distributional patterns are limited by freeze embolism along two altitudinal gradients in Chilean temperate rainforests, and what adaptations could reduce the vulnerability of lianas to embolism. We studied liana representation, embolism, vascular anatomy, and root pressure. Our results show that liana representation declines significantly with increasing altitude, and that species altitudinal and latitudinal limits are well correlated. Mean vessel diameters of liana species ranged from 36 um to 65 um, decreasing with increasing altitude. In the warm season, liana stems had between 3 and 10 times greater hydraulic conductivity than trees, but were significantly more affected by embolism in winter. Only lianas with small vessels and high root pressure reached the coldest (highest) points along the gradients, whereas trees did not show these correlations. Root pressure was present in all lianas in winter, and was sufficient to dissolve embolism at least to 2.7 meters above ground. These results suggest that distributional patterns of lianas are restricted by their vulnerability to freeze embolism, and that species with high root pressure and small vessel diameters could reduce their vulnerability to embolism allowing them to inhabit cold environments.
Key words: Liana distributional pattern, Hydraulic conductivity, embolism, Root pressure