Structural and functional changes in the photosynthetic apparatus of Chlamydomonas reinhardtii during nitrogen deprivation and replenishment.

Preininger, É.; Kósa, A.; Lőrincz, Z.; Nyitrai, P.; Simon, J.; Böddi, B.; Keresztes, Á.; Gyurján, I.

Nitrogen is an essential factor for normal plant and algal development. As a component of nucleic acids, proteins, and chlorophyll (Chl) molecules, it has a crucial role in the organization of a functioning photosynthetic apparatus. Our aim was to study the effects of nitrogen starvation in cultures of the unicellular green alga, Chlamydomonas reinhardtii, maintained on nitrogen-free, and then on nitrogen-containing medium. During the three-week-long degreening process, considerable changes were observed in the Chl content, the ratio of Chl-protein complexes, and photosynthetic activity of the cultures as well as in the ultrastructure of single chloroplasts. The regreening process was much faster then the degradation; total greening of the cells occurred within four days. The rate of regeneration depended on the nitrogen content. At least 50% of the normal nitrogen content of Tris-Acetate-Phosphate (TAP) medium was required in the medium for the complete regreening of the cells and regeneration of chloroplasts.

ELECTRON microscopy; FLUORESCENCE; PHOTOSYNTHESIS; CHLAMYDOMONAS reinhardtii; GREEN algae

Photosynthetica, 2015, Vol 53, Issue 3, p369

0300-3604

Academic Journal

10.1007/s11099-015-0129-y