Chlorophyll fluorescence and initial growth of two liana species, Cuspidaria sceptrum (Cham.) L.G. Lohmann and Fridericia florida (DC) L.G. Lohmann, under changes of natural light conditions.

The physiological alterations as well as the growth were evaluated in seedlings of two liana species, Cuspidaria sceptrum and Fridericia florida, which were transferred from shade to full sunlight conditions. We cultivated one group of seedlings under full sunlight, the second group under natural shade beneath canopy, and the third group was transferred from shade to full sunlight. Reductions on the potential quantum yield of PSII (Fv/Fm) during predawn was detected under full sunlight, but these responses were more pronounced when the plants were transferred from shade to full sunlight. C. cuspidaria lost all leaves developed under shade a few days after transfer. However, at 60 d after transfer, new leaves were already developed and their Fv/Fm values were similar to full sunlight plants. F. florida was able to maintain its leaves after transfer and exhibited gradual recovery of Fv/Fm over time. The initial photoinhibition influenced growth responses of these liana species, in spite of their heliophyte character as adult plants. [ABSTRACT FROM AUTHOR]