Abstract: In this paper, we show some of our findings from measuring the growth of free conchocelis of Porphyra haitanensis, the effects on the biosynthesis of Chl a,and the release of the shell fixed conchocelis under the different concentrations of heavy metal ions Cu. The growth of free conchocelis of Porphyra haitanensiswas inhibited severely, and the color of the conchocelis became pink, yellow, green, and then white as the concentration increased and the exposure time prolonged. We also found the higher concentration of Cu²⁺ depressed the chlorophyll content in a short time. The influence of Cu on free conchocelis in the 24h, 48h , and 72h IC₅₀ concentrations were: 3.298, 0.625, and 0.171 mg·L^-1 (estimated value), while the safe concentration was 0.0171 mg·L^-1 (estimated value). For conchospore releasing, the number of released conchospore showed a good dose-response relationship with the stress of Cu²⁺. Under low concentrations of Cu²⁺, the released conchospore number was not affected, while it was significantly inhibited at high concentration treatment.

Key words: Porphyra haitanensis, shell fixed conchocelis, free conchocelis, copper, conchospore