Are there plants able to see?
The vegetal kingdom is composed of living beings that have been a fundamental piece to shape the present life present in the world. Without the plants, it would not have been possible the massive production of oxygen that is now in the atmosphere, all generated from carbon dioxide, which allowed the appearance of other classes of multicellular beings such as animals. In addition, they are the main source of food for many organisms.
Plants have the ability to grow as well as to feel, although they do not do it in the same way as animals, nor experiencing pain. They can detect changes abroad and "learn" from these experiences. For example, there is phototropism, which is the ability to direct growth in the direction of light rays. But, Can plants present a similar sense to vision as humans? This is an idea n idea denied outright by scientists for decades, but recent studies provide data against this belief.
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The possible vision of the plants
The hypothesis that plants have the ability to see is not new. Already in 1907, the botanist Francis Darwin , son of the naturalist and father of the theory of evolution Charles Darwin, he thought about it. Known for his studies on the aforementioned phototropism, Francis let it fall that there could be an organ that was formed by the combination of a cell that acts as a lens and another that presents sensitivity to light, offering the characteristic of seeing.
Experiments of the early twentieth century proved the existence of an organ that we know today as ocelo, or simple eye , but that is present in invertebrates and not in plants. Therefore, the idea of vision in plants fell into oblivion ... until the end of last year, at which point with the appearance of a new line of research the idea is revived.
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A bacterium with sight
In a recent publication of the medium Trends in Plant Science by František Baluška, a biologist specializing in plant cells at the University of Bonn in Germany, and Stefano Mancuso, a plant physiologist at the University of Florence in Italy, new evidence appears that plants may see.
The first point highlighted by researchers is that in 2016 it was discovered that Synechocystis cyanobacterium has the ability to act as an ocellus . The cyanobacteria, which were previously also called blue-green algae, form a biological category (a phylum) that comprises unicellular organisms that have the ability to perform photosynthesis. Being prokaryotic cells, it is wrong to consider them as algae, a term that is limited only to some eukaryotic cells.
The mechanism that Synechocystis uses to generate vision is based on a curious trick: uses his own body as if it were a lens to project an image of light It reaches through its cell membrane, just like the retina does in animals. Baluška thinks that if such a capacity exists in such primitive beings, there may be a possibility in the higher plants of presenting a similar mechanism.
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Other evidence in favor
Other points that these researchers highlight are based on recent studies that reveal that some plants, such as cabbage or mustard, make proteins that are involved in the development and functionality of the eye spot or stigma, a very simple kind of eye that is present in some unicellular organisms such as green algae, which allow us to capture information regarding the direction of light.
These proteins are part of the structure of the plastoglóbs , vesicles that are inside the chloroplast (cellular organelle responsible for photosynthesis) and whose function is a mystery. Baluška suggests that this discovery may reveal that the plastoglóbs act as if they were an eye blot on higher plants.
Other observations made by researchers, drop the idea that the vision ability of plants may use systems totally different from what we currently know in complex organisms, being out of our understanding at the moment. For example, in 2014 a study appeared that showed that the vine plant Booty trifoliolata You can modify the color and shape of its leaves, imitating those of the plant that supports it. It is unknown what is the mechanism used to achieve this mimicry.
In spite of all this, in the end it is evidence and not a description of the concrete mechanism that the plants would use to see.In spite of this, the door is opened to a new path of investigation around plant physiology and biology in search of whether there really can be one or different methods to capture visual information from the medium, a resource that would allow higher plants to possess the sense of vision, as does a bacterium like Synechocystis.
