Effects of Salinity, Temperature and Light Intensity on Growth and Photo- synthetic Activity of Caulerpa sertularioides

Abstract:

In order to explore the effects of environment factors on growth of Caulerpa sertularioides, the changes in growth and chlorophyll fluorescence parameters were studied under different salinity, temperature and light intensity. The results showed that the specific growth rate (SGR), maximum light quantum yield (F_v/F_m), actual photosynthetic efficiency (Yield), electron transfer rate (ETR) and photochemical quenching (qP) increased at first and then decrease with increasing salinity, while non-photochemical quenching (qN) was opposite. The photosynthetic activity and carbon fixation efficiency of the algae under 27.5‰ salinity were the highest, and there were significant difference with those under 25‰ and 30‰ salinity (P<0.05, n=3). The SGR, F_v/F_m, Yield,

ETR and qP of the algae decreased with temperature rising, and qN was opposite. The photosynthetic activity and carbon fixation efficiency of algae under 26℃ were the highest, and there were significant difference with those under 28℃ and 30℃ (P<0.05, n=3). The SGR, F_v/F_m, Yield, ETR and qP of the algae increased at first and then decreased with increment of light intensity, while qN was opposite, and there was slight photoinhibition under 18.75 μmol/(m²·s) light intensity. The growth, photosynthetic activity and carbon fixation efficiency of algae were the highest under 25.00 μmol/(m²·s) light intensity, but no significant difference with those under 18.75 and 27.5 μmol/(m²·s) light intensity (P>0.05, n=3). Therefore, it was suggested that C. sertularioides could grow fast with high photosynthesis ability under the conditions of 27.5‰ salinity, 26℃, and 25.00 μmol/(m²·s) light intensity.