PRODUCTION LIGHT LEVEL EFFECTS ON LIGHT COMPENSATION POINT, CARBON EXCHANGE RATE AND POST-PRODUCTION LONGEVITY OF POINSETTIAS

‘Annette Hegg Dark Red’ (AHDR) and ‘Gutbier V-10 Amy’ (Amy) poinsettias were grown at a maximum photosynthetic photon flux density (PPFD) of 500 μmol s^-1m^-2 until anthesis or shifted to 300 μmol s^-1m^-2 for 1 or 3 weeks prior to anthesis.
Heights, bract diameters and dates of anthesis were not affected by shifting plants to low light.
At anthesis, light compensation point (LCP) of ‘AHDR’ plants moved to low PPFD for 3 weeks was 31 μmol s^-1m^-2 compared to 51 μmol s^-1m^-2 for plants remaining at high PPFD. Plants shifted for 1 week had an LCP of 42 μmol s^-1m^-2. Plants moved to low PPFD 3 weeks before anthesis had a higher carbon exchange rate below 250 μmol s^-1m^-2 than plants remaining at the high PPFD. Plants were moved at anthesis to interior conditions providing a constant 21°C and 20 μmol s^-1m^-2 for 12 hrs daily.
Plants remained in interior conditions for 30 days. ‘Amy’ and ‘AHDR’ plants lost fewer leaves when plants were shifted to low PPFD prior to anthesis compared to plants grown at high PPFD. These results indicate that poinsettias can be acclimatized during production.

III International Symposium on Postharvest Physiology of Ornamentals

T.A. Nell, J.E. Barrett

https://doi.org/10.17660/ActaHortic.1986.181.32