A study of the relation between CP29 phosphorylation, zeaxanthin content and fluorescence quenching parameters in Zea mays leaves

The hypothesis that phosphorylation or the minor photosystem II antenna complex CP29 (CP34 formation) in Zea mays (cv. Dekalb DK300). under conditions of illumination and low temperature stress, may constitute a protective mechanism against photoinhibition. has been investigated. It is demonstrated that illumination at low temperature induces a marked increase in reversible non-photochemical quenching yield of chlorophyll fluorescence, together with CP34 formation, These two parameters, however, are not related as CP34 dephosphorylates to CP29 in the dark, with a half-time of about 10 min, while tho enhanced non-photochemical quenching yield is stable for many hours. The enhanced non-photochemical quenching yield seems to correlate with zeaxanthin formation. The influence of CP34 formation on photoinhibition was also directly investigated. No measurable effect on this parameter could be observed after treatment with high light. It is concluded that CP34 is probably not directly involved in photoprotective processes.