FOLIAR UPTAKE CAPACITY OF SOUTHERN CALIFORNIA PLANTS IN COASTAL AND INLAND FOG SYSTEMS
Nathan Vega, Joseph Gamez, Jordan Abney, Stacy Schkoda, Austin Xu, Darren Sandquist, William Hoese.
California State University, Fullerton, Fullerton, CA.
Plants absorb water left on leaf surfaces from rain, dew, and fog via foliar uptake. In some species, foliar uptake capacity varies in proportion to fog frequency and duration. Southern California experiences intermittent fog during the dry season, possibly reducing water stress through foliar uptake in local plants. To determine if there were differences in foliar uptake between coastal and inland plant communities, we sampled at Alta Laguna, California (<1mi. inland) and Trabuco Canyon, California (~15 mi. inland). We sampled Malosma laurina (laurel sumac), Salvia mellifera (black sage), Heteromeles arbutifolia (toyon), and Quercus agrifolia (coast live oak) because they were common native plants found at both sites. We hypothesized that plants at Alta Laguna would absorb significantly higher amounts of water through foliar uptake since coastal areas experience a higher fog frequency and duration than inland regions. Leaves were weighed, misted, and incubated in a chamber at 100% humidity with control leaves subjected to the same treatment without misting. After incubation the leaves were weighed to determine if absorption had occurred. Water potential was measured before and after incubation. Toyon at Starr Ranch, laurel sumac at both locations, and black sage at Alta Laguna performed foliar uptake. At both locations, toyon showed a significant increase in water potential post-incubation. There was no difference in foliar uptake capacity between areas with varying fog frequency and duration. Several species performed foliar uptake, and as temperatures increase and fog frequency and duration decrease, these plants may lose access to water in the dry season.