Antioxidants and xanthophyll cycle-dependent energy dissipation in Cucurbita pepo L. and Vinca major L. acclimated to four growth PPFDs in the field

to those exhibited by xanthophyll cycle-dependent energy dissipation. The patterns of acclimation of The acclimation of photochemistry, xanthophyll cycleglutathione reductase are discussed in the context of dependent energy dissipation, and antioxidants was the multiple roles for reduced glutathione. Catalase characterized in leaves of Cucurbita pepo L. and Vinca acclimated in a manner consistent with its role in major L. that developed under photosynthetic photon scavenging H 2 O 2 generated via photorespiration flux densities (PPFDs) ranging from deep shade to full and/or mitochondrial respiration. Leaf a-tocopherol did sunlight in the field. The predominant acclimatory not exhibit growth PPFD-dependent trends. response of leaf pigment composition was an increase in the xanthophyll cycle pool size with increasing