Most of us don't normally think of the color "purple" when we think about plants unless we're thinking about their flowers. But purple plants do happen! And when we see this color in plants it is often caused by a pigment called "anthocyanin". This is the same pigment that makes purple cabbage purple! When was the last time you saw purple plants outside of the Conservatory?
There are several hypotheses about why some plants might have more purple color in their leaves. It may protect them from insect predators by making them less attractive. New leaves on plants look a little red or purple because anthocyanin can protect these fresh leaves from getting sun damage (yes, plants can get sunburnt just like us!). In adult leaves, anthocyanin can help plants absorb more visible light, so it may be helpful for plants living in areas with low light levels.
Many plants that live on the rainforest will also have red or purple undersides to their leaves. While there's no agreement between scientists exactly why this is, researchers have proposed a few ideas. The first hypothesis says that anthocyanin acts as protection against fungal infection (which can wreak havoc on plants in the wet and humid rainforest). The second states that anthocyanin may help absorb free radicals that hit the top of the leaf and prevent cellular damage.
Garfield Park Conservatory Alliance is a 501(c)3 non-profit organization that changes lives through the power of nature. We inspire, educate and provoke exploration through innovative programs and experiences in one of the nation’s largest and finest historic conservatories.