Abstract
Photoautotrophic cells provide a unique system for photosynthetic research. We have studied the high light adaptation of photoautotrophic cell culture of Petunia hybrida. The cells grown under high light condition (HL cells) had larger total pool size of xanthophyll cycle pigments, that is total contents of violaxanthin, antheraxanthin and zeaxanthin, and higher violaxanthin ratio which can be converted by zeaxanthin after photoinhibitory treatment in comparison with low light grown cells (LL cells). The distribution of the xanthophyll cycle pigments among photosynthetic pigment-protein complexes in the thylakoid was examined after dark adaptation and after photoinhibitory treatment. The fraction containing major LHCII and minor LHCII induced more zeaxanthin after photoinhibitory treatment in both cells. LHCII proteins in HL cells had more xanthophyll molecules per polypeptide and higher zeaxanthin even after dark adaptation, suggesting that the LHCII proteins in HL cell had extra zeaxanthin.
