title: Adaptation of the obligate CAM plant Clusia alata to light stress: Metabolic responses.
abstract: In the Crassulacean acid metabolism (CAM) plants Clusia alata Triana and Planch., decarboxylation of citrate during phase III of CAM took place later than malate decarboxylation. The interdependence of these two CO(2) and NADPH sources is discussed. High light accelerated malate decarboxylation during the day and lowered citrate levels. Strong light stress also activated mechanisms that can protect the plant against oxidative stress. Upon transfer from low light (200micromol m(-2)s(-1)) to high light (650-740micromol m(-2)s(-1)), after 2 days, there was a transient increase of non-photochemical quenching (NPQ) of fluorescence of chlorophyll a of photosystem II. This indicated acute photoinhibition, which declined again after 7 days of exposure. Conversely, after 1 week exposure to high light, the mechanisms of interconversion of violaxanthin (V), antheraxanthin (A), zeaxanthin (Z) (epoxydation/de-epoxydation) were activated. This was accompanied by an increase in pigment levels at dawn and dusk.
authors: Institute of Biology, Pedagogical University, 31-054 Krakow, ul. Podbrzezie 3, Poland.
authors: Andrzej
authors: A
authors: Kornas
authors: Elke
authors: E
authors: Fischer-Schliebs
authors: Ulrich
authors: U
authors: Lüttge
authors: Zbigniew
authors: Z
authors: Miszalski
mesh_terms: D000222:Adaptation, Physiological; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D019343:Citric Acid / Q000378:metabolism; D031251:Clusia / Q000378:metabolism / Q000502:physiology / Q000528:radiation effects*; D003653:Decarboxylation / Q000528:radiation effects; D005453:Fluorescence; D008027:Light; D008293:Malates / Q000378:metabolism; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism; D013312:Stress, Physiological; D024341:Xanthophylls / Q000378:metabolism; D065146:Zeaxanthins
chemical_list: D008293:Malates; D045332:Photosystem II Protein Complex; D024341:Xanthophylls; D065146:Zeaxanthins; C031140:antheraxanthin; D002734:Chlorophyll; D019343:Citric Acid; C005613:violaxanthin; C030298:malic acid; D000077194:Chlorophyll A