Meeting Abstract
P2.219 Saturday, Jan. 5 PAM analysis of 3 sacoglossan species reveals differences in photosynthetic function and chloroplast longevity CURTIS, NE**; MIDDLEBROOKS, ML; SCHWARTZ, JA; PIERCE, SK; Rollins College; Univ. of South Florida; Univ. of South Florida; Univ. of South Florida ncurtis@rollins.edu
The sea slug Elysia clarki sequesters photosynthetically functional chloroplasts from at least a dozen algal species and maintains these plastids for up to 4 months. Elysia patina and Placida kingstoni also feed on some of the same species, but cannot maintain plastids longer than 2 weeks. We starved E. clarki, E. patina, and P. kingstoni until they lost their green coloration, and then E. clarki were fed on either Bryopsis plumosa or Penicillus lamourouxi, while E. patina were fed P. capitatus and P. kingstoni were fed B. plumosa. Photosynthetic activity was measured using PAM analysis and the slugs were immediately re-starved. PAM measurements continued with starvation until photosynthesis ceased. Initially, P. lamourouxi and B. plumosa fed E. clarki had photosynthetic rates that were statistically equivalent. However, as length of starvation increased, photosynthetic rates decreased. After 12 weeks, B. plumosa fed E. clarki were not photosynthesizing, while P. lamourouxi fed E. clarki still had some PAM activity. Also, P. capitatus fed E. clarki (published previously) had lower PAM values than either B. plumosa fed or P. lamourouxi fed E. clarki at 0 weeks starvation, but higher values at 4 and 12 weeks starvation. Freshly fed E. patina had photosynthetic activity initially, which declined over the next 12 days of starvation. Freshly fed P. kingstoni specimens also had immediate photosynthetic activity, but it rapidly dropped to 0 over the next 4 hours of starvation. Thus, longevity and photosynthetic activity of sequestered chloroplasts in E. clarki depends on the algal source. However, among slug species, specific adaptations account for the tremendous variation in the length and functionality of these kleptoplastic associations.
