Carotenoid composition and down regulation of photosystem II in three conifer species during the winter [xanthophyll cycle, zeaxanthin]

carotenoide carotenoides carotenoids chlorophylle chlorophylls clorofilas cold estres fluorescence fluorescencia fotosistemas frio froid hiver invierno photoinhibition photosynthese photosynthesis photosystems picea pungens pinus ponderosa pseudotsuga menziesii resistencia a la temperatura stress summer temperatura temperature temperature resistance verano winter