Daily and seasonal variations of optimum quantum yield and phenolic compounds in Cystoseira tamariscifolia (Phaeophyta)

摘要: Effects of solar radiation on phenolic compound concentrations and photosynthetic activity, estimated as in vivo chlorophyll fluorescence, the brown alga Cystoseira tamariscifolia (Hudson) Papenfuss were analyzed southern Spain from June 1988 to July 2000. Annual diurnal variations optimum quantum yield negatively correlated with incident irradiance. Optimum decreased irradiance increased at noon, values recovered afternoon suggesting a dynamic photoinhibition. The annual daily fluctuations concentration tissue C. showed contrasting patterns. There was an cycle apical thallus, which positively increase compounds, however, twofold greater first half year than decrease during second year. In contrast cycle, there appeared be negative correlation between summer months while no specific relationship observed fall–winter months. Loss compounds surrounding water irradiation dosage increased. This suggests that might regulated by exudation these high irradiances field. Collectively, our results suggest that, like photoinhibition, rapid synthesis turnover time serve photoprotective mechanisms against irradiances.