PARENT SESSION
Poster Session # 13: Biogeochemistry, Photosynthesis, and Respiration.
Tuesday, August 5 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Growth responses of the federally endangered shrub, Lindera melissifolia (pondberry), to varied light environments.
Aleric, Katherine*,1, 2, Kirkman, L. Katherine1, 1 J.W. Jones Ecological Research Center, Newton, GA2 University of Georgia, Athens, GA
ABSTRACT- Lindera melissifolia, pondberry, is a federally endangered shrub that occurs in seasonally flooded wetlands. Although pondberry populations occur in dense shade and full sun environments, the optimal conditions for growth are unclear and differences in observations have led to conflicting management interpretations. Increasing vigor of existing populations is critical for species persistence, particularly due to low sexual reproduction. The goal of this study is to determine the optimal light requirements for growth by comparing morphological and photosynthetic responses of plants growing under natural and controlled light environments. In the first year of this study, growth responses and light conditions were measured in three natural populations in Georgia and South Carolina. Preliminary findings indicate that pondberry has the ability to acclimate to varied light conditions by displaying typical sun-shade morphological and photosynthetic responses. Photosynthetic capacity was consistent with other shade tolerant species with maximum rates of photosynthesis ranging between 2-8 
mol CO2m-2s-1. Leaves became saturated at relatively low light levels of 250-400 mol m-2s-1 PAR. The low photosynthetic capacity and saturation irradiance found even in high light environments suggests that this species is adapted to low light conditions. Currently, plants propagated by cuttings are being grown in three light treatments using shade cloth over support frames. Cuttings have also been outplanted in contrasting canopy cover in four wetland sites at Ichauway, the J.W. Jones Ecological Research Center. The information from both field and controlled experiments will be used to develop management strategies for the removal of competing vegetation, if necessary, and in identifying suitable sites for new population establishment.
Key words: light, Lindera melissifolia, photosynthesis, morphology