THE INFLUENCE OF IRRADIANCE ON ETHYLENE SENSITIVITY AND POSTPRODUCTION QUALITY OF PELARGONIUM X DOMESTICUM

The objective of this research was to determine if irradiance affects postproduction quality of Pelargonium Xdomesticum. Plants of varieties with good and poor postproduction quality were forced in a growth chamber at two irradiance levels. 250 and 450 μmoles s^-1 m^-2. Temperature was maintained at 21/16°C day/night with an 18 h photoperiod.
Plants grown at high irradiance had reduced leaf area per plant, less area per leaf and greater specific leaf weight than plants grown at lower irradiance.
Increased irradiance during production significantly shortened the time to flowering but did not affect the number of florets produced.
Petal abscission following a 1 h exposure to 0.7 μl 1^-1 ethylene was not significantly different between plants grown at two irradiances.
No varietal differences in ethylene sensitivity were found.
Plants from the two production environments did not differ in keeping quality or in net carbon exchange at irradiances of 0, 15, 30 and 60 μ1moles s^-1m^-2. The variety exhibiting lower postproduction longevity had a higher dark respiration rate.
In all plants a net positive carbon balance was achieved between irradiances of 30 and 60 μmoles s^-1 m^-2.

Symposium on Bedding and Pot Plant Culture

Karen M. Olson, K. B. Evensen

https://doi.org/10.17660/ActaHortic.1990.272.50