Effect of desiccation on photosynthesis and respiration of red alga Gelidiella acerosa (Rhodophyta, Gelidiales)

Respiration and photosynthesis were measured for Gelidiella acerosa under laboratory conditions when they were desiccated to 0, 10, 20, 30, 40 and 50%. Rates of gross and net photosynthesis decreased with increasing percentage of desiccation, but even after 50% desiccation the plants were able to maintain positive net photosynthesis. Plants growing on tidal flats (partially emerged) had low photosynthetic rates as compared to those growing in tide pools (completely submerged). Plants desiccated up to 20% were able to maintain the rate of gross and net photosynthesis even during longer incubation periods. In plants desiccated above 30% the rates of respiration, gross and net photosynthesis steadily decreased with increase in incubation time.