Walking through nature with John Palka, a neuroscientist who loves plants and ponders big questions
Many of us enjoy the brisk cold of winter, especially out here in Minnesota. Hardy mammals and birds at least tolerate the frigid weather. But what about plants? No fur or feathers. No moving out of the wind or digging a cozy burrow under the snow. What keeps trees and bushes from literally freezing to death in the cold mid-winter?
I like to think of the forest as not only teeming with life, but also as breathing. Let me explain what I have in mind.
In the mid-1970s I had a remarkable experience while walking in ancient forests on the west side of the Cascade Mountains of Washington. . . I was grasping an essential truth that was based on familiar science (relating to genes), but the nature of the grasping had a quality that I was not able to put into words, and that, even if I could, a scientific journal would probably never allow to be published on its pages.
Without the green of the forests and the fields, and also of the plankton floating in the upper layers of the oceans, the lives of the Earth’s animals, including our lives as human beings, would not be possible. Where does all this magical green come from? It comes from the presence of the pigment chlorophyll in the cells of the leaves and whatever other parts of a plant are green.
Suppose we take a walk in the springtime woods. In the wettest places, the green leaves of the spectacular swamp lanterns blend in well with the surrounding plants, including the mosses, ferns, gymnosperms, and angiosperms we met in a previous post. In contrast, the flowering heads—the lanterns—seem to truly glow a brilliant yellow. Why are the two parts of a single plant so different from one another?
The plants on Yellow Island, situated in the northwestern corner of Washington State, glow with literally all the colors of the rainbow, from blue, through green and yellow, and on to orange and red. They call out a question that scientists and philosophers have asked literally for centuries—how do leaves and flowers come to have the colors they do? Indeed, why are objects of any kind seen by us as having distinguishable colors?