Biology

Some Plants May Have a Sense of Sight

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Are you decent? You may want to cover up. Research suggests that plants may have the gift of sight. (Don't worry, they can't actually see you.)

The Eyes of the Forest

Before we share the evidence, we should back up: This isn't really anything new. Way back in 1907, Francis Darwin — the son of the one and only Charles Darwin — argued the same thing. He theorized that plant leaves have organs made up of lens-like cells and light-sensitive cells, organs now called ocelli. You can see ocelli, sometimes called simple eyes, in all sorts of animals; some arthropods have them, for example, as do sea creatures like jellyfish and sea stars. But plants? Now that would be surprising.
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Darwin's theory was all but forgotten until recently, when a new wave of something called plant neurobiology started gaining steam. In a November 2016 issue of Trends in Plant Science, scientists Stefano Manusco and František Baluška laid out the case for plants having something akin to an eye. Exhibit A: Earlier in 2016, researchers discovered that an ancient species of cyanobacteria actually act like tiny lenses in what is "probably the world's smallest and oldest example of a camera eye." It's reasonable to assume that if an organism that primitive has such an ability, further-evolved organisms such as plants probably do too.
Exhibit B, according to Scientific American, is that "some plants, such as the cabbage and mustard relative Arabidopsis, make proteins that are involved in the development and functioning of eyespots — the ultrabasic eyes found in some single-celled organisms such as green algae." And then there's the mind-bending fact that the climbing vine Boquila trifoliolata can change its leaves to look like those of the plant it's climbing. We don't know that it uses vision to achieve this, but it's a possibility.

What This Means About Plants

Recent scientific research has proven that plants are way more complex than we give them credit for. Plants communicate through the air and their root structures and even show a plant version of cognition. Manusco and Baluška say in a 2007 paper, "... in order to adapt, all organisms continuously generate hypotheses about their environment via well formulated 'questions' which are solved by an increasing set of possible 'answers' in order to adapt." Plants included. There's a lot more going on in those leaves and roots than we previously thought.