Are there plants capable of seeing?

Studies show signs that plants may know their environment better than we think.

The plant kingdom is composed of living beings that have been a fundamental piece in shaping the current life present in the world. Without plants, the massive production of oxygen now found in the atmosphere would not have been possible, all generated from carbon dioxide, which allowed the appearance of other kinds of multicellular beings such as animals. In addition, they are the main source of food for many organisms.

Plants have the capacity to grow as well as to feel, although they do not do so in the same way as animals, nor do they experience pain. They can detect changes in the outside world 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 have a similar sense of vision as humans? This is an idea flatly denied by scientists for decades, but recent studies provide data against this belief.

The possible vision of plants

The hypothesis that plants have the ability of vision is not new. As early as 1907, botanist Francis Darwinson of the naturalist and father of the theory of evolution Charles Darwin, thought about it. Known for his studies on the aforementioned phototropism, Francis suggested that there could be an organ formed by the combination of a cell that acts as a lens and another cell that is sensitive to light, offering the characteristic of seeing.

Experiments at the beginning of the 20th century proved the existence of an organ we know today as the an organ that we know today as the ocellus, or simple eye.but that it is present in invertebrates and not in plants. Therefore, the idea of vision in plants fell into oblivion ... until late last year, when with the emergence of a new line of research the idea is revived again.

A bacterium with a view

In a recent publication of the medium Trends in Plant Science by František Baluška, a plant cell biologist at the University of Bonn in Germany, and Stefano Mancuso, a plant physiologist at the University of Florence in Italy, new evidence emerges that plants may indeed see.

The first point the researchers highlight is that in 2016 it was discovered that the cyanobacterium Synechocystis has the ability to act like an ocellus.. Cyanobacteria, which were formerly also called blue-green algae, form a Biological category (a phylum) comprising unicellular organisms that have the ability to photosynthesize. Being prokaryotic cells, it is erroneous to consider them as algae, a term that is limited only to some eukaryotic cells.

The mechanism used by Synechocystis to generate vision is based on a curious trick: it uses its own body as if it were a lens to project an image from the light that arrives through its cell membrane, just as the retina does in animals. Baluška believes that if this ability exists in such primitive beings, it may be possible for higher plants to have a similar mechanism.

Other evidence in favor

Other points highlighted by these researchers are based on recent studies that reveal that some plants, such as cabbage or mustard, manufacture proteins that are involved in the development and functionality of the eyespot or stigma, a very simple kind of eye that is present in some unicellular organisms such as green algae, which allow them to capture information regarding the direction of light.

These proteins are specifically part of the structure of the plastoglobulesThese proteins are specifically part of the structure of plastoglobules, vesicles found inside the chloroplast (the cell organelle responsible for photosynthesis) and whose function remains a mystery. Baluška suggests that this discovery may reveal that plastoglobules act as an eyespot for higher plants.

Other observations made by researchers, drop the idea that the vision capacity of plants may use totally different systems to what we currently know in complex organisms, being for the moment out of our understanding. For example, in 2014 a study appeared showing that the climbing plant Boquila trifoliolata can modify the color and shape of its leaves, mimicking those of the plant that supports it. The mechanism used to achieve this mimicry is unknown.

In spite of all that has been said, in the end this is evidence and not a description of the concrete mechanism that the plants would use to see. Nevertheless, this opens the door to a new avenue of research into plant physiology and biology in search of whether there really can be one or more methods for capturing visual information from the environment, a resource that would allow higher plants to possess the sense of vision, just as a bacterium such as Synechocystis has it.