Leaves Change Colors Under Different Lighting

a fern with blue leaves sits against a lush green background

Biological Strategy

Willdenow's spikemoss

AskNature Team

Image: Scott Zona / Flickr / CC BY - Creative Commons Attribution alone

Adapt Phenotype

Living systems evolve over time in response to selective pressures. Selective pressures are environmental factors that reduce the reproductive success of some individuals in a population. Genetic makeup (genotype) is one way in which living systems mitigate selective pressures, but another is adaptable phenotypes. A phenotype is an observable characteristic that can be thought of as the expression of the genotype, combined with modifications caused by the environment or developmental conditions. Individuals, populations, or ecosystems that have phenotypes capable of reducing the effects of selective pressures can survive. Some plants, for example, modify their leaf shape in response to changing environmental conditions. A single olive tree has variable leaf shapes on sunny compared to shady areas of the tree, yet the next year, those same buds may develop differently shaped leaves.

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Mosses

Division Bryophyta (“moss plant”): Mosses, liverworts, hornworts

Bryophytes are one of the oldest groups of plants, appearing more than 500 million years ago in the Cambrian Period. Mosses are non-vascular, non-flowering, water-loving plants, often cushioning the floor of forests in dense mats. Unlike angiosperms or gymnosperms, mosses do not have fruits or seeds––they reproduce through spores. Currently, there are approximately 12,000 known species of mosses and their relatives. Sphagnum moss has been particularly useful to humans, as a key element in peat, and as a dressing for wounds in traditional cultures and along the battlelines of World War I.

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Leaves of extreme shade Selaginella tropical ferns change in improving light conditions from being iridescent blue to green by removal of photoprotective coating.

Image: Foozi Saad, Malaysia /

The photo was made with long exposure time and shows the iridescent blue color of this extreme shade plant.

Image: Scott Zona /

“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