Temperature optima for growth and photosynthetic processes in Trebouxia erici isolated from an Antarctic lichen and cultivated in a temperature gradient

Abstract

The temperature optimum for photosynthesis and growth of natural populations of Trebouxia erici isolated from an Antarctic lichen (Usnea antarctica) was determined using a long-term cultivation (26 days) at different temperatures. Several chlorophyll fluorescence parameters were used in T. erici cultivated in a liquid medium to assess the effect of cultivation temperature (0, 10, 20 and 30oC). Analysis of time courses of the capacity of photosynthetic processes in PS II (FV/FM), effective quantum yield of photosystem II (FPSII), relative fluorescence decline ratio (RFd), and quenching of background chlorophyll fluorescence (qF0) revealed that optimum temperature is between 10 to 20°C. Biomass production evaluated as a total chlorophyll production after 26 days of cultivation was maximal at 20°C. The results are discussed in relation to the data reported by other literature sources for Trebouxia sp. and other algae isolated from chlorolichens.