Leaves of extreme shade Selaginella tropical ferns change in improving light conditions from being iridescent blue to green by removal of photoprotective coating.
The photo was made with long exposure time and shows the iridescent blue color of this extreme shade plant.
“Blue iridescence is most common in the genus Selaginella. The two taxa analysed here are native to the extreme shade of humid tropical forests: S. willdenowii (Desv.) Bak. in Southeast Asia and S. uncinata Spr. in South China. In both species blue iridescence develops on leaves in shade beneath foliage. The green leaves that develop in response to more direct sunlight do not become blue when subjected to this shade, but blue leaves gradually turn to green with age or exposure to more direct light (pers. observ.). The filtering action of the forest foliage produces an environment deficient in energy for , with only 0.1-0.3% of the light above the canopy (Bjorkman and Ludlow, 1972; Bazzaz and Pickett, 1980).” (Hebant and Lee 1984:216
Ultrastructural Basis and Developmental Control of Blue Iridescence in Selaginella Leaves
Charles Hebant; David W. Lee
American Journal of Botany, Vol. 71, No.2 (Feb., 1984), 216-219.
Stable URL: http://links.jstor.org/sici?sici=0002-9122%28198402%2971
