ACCLIMATIZATION OF DORITAENOPSIS HYBRID ORCHIDS AS AFFECTED BY PPF LEVELS

Doritaenopsis orchids ‘New Candy’ were propagated in vitro for 3 months and transferred to ex vitro for acclimatization under different PPF levels: 50, 100, 150, 200, and 300 μmol m^-2 s^-1. Leaf RWC started to decrease at all PPF levels, which was significant under high PPFs (200 and 300 μmol m^-2 s^-1) especially until 5 days of acclimatization.
Little changes were observed at low PPFs (50, 100 and 150 μmol m^-2 s^-1), showing higher leaf RWC after 30 days of acclimatization compared with high PPF levels.
Changes of Fv/Fm value were similar to those of leaf RWC. High PPFs (200 and 300 μmol m^-2 s^-1) induced rapid decreases of FV/Fm in the plantlets after 2 days of acclimatization, which were recovered from the 5th day but the FV/Fm value was lower than that under low PPFs (50, 100 and 150 μmol m^-2 s^-1) until the end of acclimatization period.
PPF levels also affected growth responses of the plantlets.
Low PPFs (50, 100 and 150 μmol m^-2 s^-1) resulted in higher growth and survival rate, while high PPFs (200 and 300 μmol m^-2 s^-1) inhibited them.
Especially, plantlet growth was severely suppressed at 300 μmol m^-2 s^-1 and as a result plantlet survival rate reached only 75%. The results suggested that physiological acclimatization occurs at 100 and 150 µmol m^-2 s^-1, which was correlated with a photosynthetic compensation point for Doritaenopsis hybrid orchids.

III International Symposium on Acclimatization and Establishment of Micropropagated Plants

E.-J. Hahn, M.-W. Jeon, E.-J. Lee, K.Y. Paek

acclimatization, Doritaenopsis, photosynthetic photon flux, photoinhibition

https://doi.org/10.17660/ActaHortic.2009.812.62