Abstract: Prorocentrum donghaiense is one of the dominant species in harmful algal blooms. To understand the physiological and biochemical responses of P. donghaiense under stress of linolenic acid secreted by macroalgae, the growth, photosynthetic efficiency and the activities of antioxidant enzymes of algal cells were investigated. The results showed that low concentration(<200 μg·L^-1) of linolenic acid promoted the growth ofP. donghaiense. With the increase of linolenic acid concentration from 200 to 1000 μg·L^-1, the growth ofP. donghaiense was inhibited, with the inhibitory rate being up to 90% within 48 h at the concentration of 1000 μg·L^-1. At 200-1000 μg·L^-1 linolenic acid, the contents of photosynthetic pigment and the quantumefficiency (F_v/F_m) of P. donghaiense decreased. When the concentration of linolenic acid was 1000 μg·L^-1, the F_v/F_m ofP. donghaiense was 33.87% of that in the control. The activities of CAT, SOD and GPx, and the contents of GSH, GSSG, AsA and DHA in P. donghaiense cells first increased and then decreased with increasing concentrations of linolenic acid. The content of MDA increased sharply with the increase of linolenic acid concentration, indicating that the level of membrane lipid peroxidation intensified. Our results suggested that the growth of P. donghaiense was promoted at low concentration of linolenic acid but was inhibited at high concentration mainly due to the reduction of photosynthetic efficiency and the damage of membrane lipid peroxidation, which provides a scientific basis for the prevention and control of red tide caused by P. donghaiense.

Key words: BIOME-BGC model, aboveground carbon storage, spatiotemporal simulation, environmental factor., bamboo forest