A PRELIMINARY STUDY OF THE EFFECT OF ULTRAVIOLET RADIATION ON VISIBLE FLOWER COLORATION IN TWO ORCHIDS

Very little UV-A (315 to 400 nm) and UV-B (280 to 315 nm) radiation is transmitted through polycarbonate-acrylic (PC-A) panels, and in an earlier study, red lettuce leaves grown under PC-A panels were mostly green.
However, red lettuce leaves grown under the UV-radiation transmitting, ethylene-tetrafluoroethylene copolymer film (F-Clean) were dark red in color.
In the study reported here, orchid plants were grown under PC-A panels and 30 and 100% UV-radiation transmitting films to determine the effects of UV-radiation on flower color.
The red-purple flowers of Burrageara Stefen Isler ‘Lava Flow’ grown with very little UV-radiation under the PC-A panels appeared to be only slightly lighter in coloration then those grown under 30 and 100% UV-radiation transmitting films.
The yellow-bronze flowers of Odontocidium Tiger Crow ‘Golden Girl’ grown with very little UV-radiation under the PC-A panels also appeared to be only slightly lighter in coloration then those grown under 30 and 100% UV-radiation transmitting films.
Apparently, UV radiation in these orchid flowers is not as critical a factor in coloration as it is in leaves of red lettuce.

I International Orchid Symposium

W.S. Sakai, E. Band, J. Edwards, R. Shioshita, J. Fang

anthocyanins, Burrageara, carotenoids, Odontocidium, UV

https://doi.org/10.17660/ActaHortic.2010.878.46