Abstract: This paper determined the fluorescence emission spectrum at 77 K of four diatoms Phaeodactylum tricornutum,Cheatoceros mulleri,Skeletonema costatum and Pseudo-nitzschia pungens and three chrysophytas Isochrysis zhanjiangensis, Pavlova viridis and Phaeocystis globosa, with that of other algae in Chromaphytae and of higher plant Spinacia oleracea compared. The results showed that these four diatoms and three chrysophytas had a similar fluorescence emission spectrum at 77 K,i.e., a significant major fluorescence emission at 684～686 nm and a not significant shoulder peak near 700 nm from thylakoid membrane, and had no fluorescence emission at 730 nm, the characteristic of PS I in higher plants, which were consistent with the spectral properties of brown algae in Chromaphytae. It was suggested that the lack of longwavelength fluorescence emission at 730 nm from PS I in Chromaphytae might be of common, predicting the great differences of PS I structure and energy transfer between Chromaphytae algae and higher plants.

Key words: Moina mongolica, Intrinsic increasing rate(r_m), Temperature, Salinity