What is the botanic equivalent to eyes

Question

There have been many questions of moving, floral animals, most of these focus on their intelligence, but what about their sense of sight. I fail to understand how a botanic based alien would be able to see, theoretically they could evolve them from the very start as light patches, like animals did, but I would rather not cop out like that. How can I explain how my botanic aliens sense of sight works?

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Answer 1

Current plants already react to light; every plant will "seek out" light by growing their shoots towards a light souce, and grow roots in the other direction. You can see it yourself if you grow plants indoors, how they will apear to lean towards windows as they grow. Plants can react even faster, with sunflowers slowly rotating as the sun progresses across the sky, or flower blooms opening during the day and closing at night. Carolus Linnaeus proposed a Horologium Florae made of beds of fourty-three types of flowers that would open and close at different times of day, like a sundial of blooms.

The mechanisms are there, corresponding to the light-sensitive patches of skin on animals. You could use mad science to make these processes more efficient (along with the rest of the plant metabolism so it can react at animal-like speeds), or a lot of time and environmental handwavium for encouraging light-sensing traits in plants. Animals improved their light-sensing by having a polyp half-covered in sensors and a small aperture, using part of their meat as a pinhole-camera; it's very efficient for not much expense so I'd expect the same mechanism in other creatures that will have distance vision. A plant with a pinhole-camera pod would have a much better time of it with a focusing lens, as it would resolve fine detail faster and with a smaller pinhole-pod, and the lens can physically close the pinhole keeping the pinhole-pod clean of dust or other opaque substances that would cover the light-sensitive parts. Perhaps the first lenses would be a drop of water, as they're very transparent and flexible, later evolving to a transparent sap that will hold its shape and less likely to evaporate.

Now, where's the organ that collects this sensory data and turns it into perception? and does it quickly? That's the real thistle of the puzzle.

Answer 2

Well plants are already covered with light sensitive molecules: chlorophylle.

You could easily imagine this evolving into a multi faceted eye like the flies except they could see from everywhere.

You could even consider a weakness which their enemies/predators could use: they could be blind to anything underneath them. Which they may have fixed with sensing whiskers for their locomotion.

Answer 3

Purpose of sight

It's worth considering that the only reason why animals have eyes is that they can an do take useful actions in response to what they see.

Many current plants have an ability to sense light, direction of light and (for example) track the sun throughout the day - this is the limit to what their eyesight is useful for them. Being able to observer rapid changes in light is not useful if the plant cannot react rapidly, so such an "eye" would be removed by evolution and replaced with something "cheaper". Gaining an accurate picture is not useful if the plant either isn't able to act or react with such accuracy, or can do it by iterative refining, slowly growing towards something.

In essence, if a plant has powerful eyesight and a visual cortex that's able to track moving objects, then that's a strong indication that the plant is capable of rapid and accurate movements to react to those moving objects, unlike the plants of our world, otherwise these eyes make no sense - they would/could evolve after a mobile or active plant, so there would/could be some mobile/active plants that are nearly blind (just photosensitive), but there would be no stationary plants sitting and looking around.