MadSci Network: Botany

Re: WHY does colored light affect the growth of plants?

Date: Wed Apr 16 19:39:02 2003
Posted By: David Hershey, Faculty, Botany, NA
Area of science: Botany
ID: 1050459928.Bt

Why questions are often difficult to answer. Plants respond differently to 
various colors, or wavelengths, of light because they have evolved pigments 
that preferentially absorb one color more than others. For example, phototropin 
is a pigment that preferentially absorbs blue light. Phototropin causes 
phototropism, a bending response toward a light source. Therefore, phototropism 
only occurs if the light source contains blue wavelengths.

Being able to sense different colors of light with pigments allows plants to 
respond to their environment in several ways. For example, being able to 
differentiate between red and far-red light with the pigment phytochrome allows 
plants to sense the daylength, or photoperiod, and thus, the time of year. 
Phytochrome is important in timing of flower production and determining when 
deciduous trees lose their leaves and go dormant in the fall. 

For more details, try searching for photomorphogenesis, which is defined as 
light regulation of plant growth and development.


Phototropism - Do Fast Plants Prefer the Blues

Photomorphogenesis, Phytochrome

Use of Light Quality to Regulate Horticultural Crop Morphogenesis

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