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The skills for calculation and arithmetic are not exclusive, as much as it weighs us, of the Homo sapiens. They have also been observed in other animals, such as sharks, pigeons, macaques, coots, and even ants.
And it is that some time ago that scientists discovered that certain ants of the species Catapglyphis fortis they are able to count their steps when they leave the anthill, which will help them find their way back more easily.
What is perhaps not so well known is the arithmetic skill that some plants display. One of them, probably the most studied, is the venus flytrap (Dionaea muscipula), a carnivorous plant.
We have long known that when soil nutrients are scarce this plant feeds on insects and arachnids.
To do this, it has the help of some sensor hairs located on the surface of its leaves with which it is able to detect the presence of a prey. However, a first contact with the sensor hair is not enough to close the trap since it could be a false alarm and the closing mechanism entails a high energy expenditure that cannot be allowed at that time.
To avoid metabolic waste, the plant has to ‘count’ how many sensor hairs have been activated before ‘giving the order’ to close. But this is not enough either, since this activation has to take place in a not too long time.
The scientists observed that when a second contact occurs in less than thirty seconds, the capture organ of the Venus flytrap is activated and the bolt is produced. Next, jasmonate is released, a phytohormone of lipid origin that stimulates the production of digestive enzymes while initiating the expression of certain transporters aimed at capturing nutrients derived from digestion.
At this point, the more sensors that are activated – provoked by a desperate attempt by the prey to flee – the greater the number of digestive enzymes that are released. Somehow the ‘mathematical count’ unbalances the cost-benefit balance on the benefit side.
Calculus for the night
During the day, plants carry out photosynthesis, an essential process for their growth and through which they use atmospheric carbon dioxide and the energy provided by sunlight to synthesize organic matter. When night falls, for obvious reasons, photosynthesis is suspended and the plant has to use its reserves of carbohydrates -starch- to provide energy for its metabolism.
Now, how does the plant effectively manage the starch stock? This question is not trivial since the sun does not always set at the same time and because it can happen that we raise the blinds at different times throughout the week, lengthening or shortening the ‘sleep’ of our indoor plants.
To answer these questions, scientists studied a herbaceous plant, the Arabidopsis thaliana, the favorite of laboratory experiments. Her study basically consisted of subjecting different plants to nights of varying lengths and seeing what happened to the starch resources. Invariably, all plants consumed 95% of the starch resources they had accumulated during the day, regardless of the length of the night. This means that, in some way, the plants were able to assess the length of the night and control the rate of consumption throughout it.
Scientists at the John Innes Center in the United Kingdom are convinced that the plant performs arithmetic divisions between two molecules, one they named ‘S’ (starch, starch), which informs them of the amount of sugar available at sunset, and another that they called ‘T’ (time, time), which provides them with information about the time left until sunrise. The ratio between S and T is key to avoid ‘fainting’ during the night hours.
Pedro Gargantilla is an internist at El Escorial Hospital (Madrid) and the author of several popular books.
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