Can plants enumerate 1-10 on their root tendrils? No. But scientists say certain plants can 'count' and even do simple maths because they possess uncanny abilities to keep tabs on insect invaders and their own food stores.
Venus flytraps, for example, famously snap their leaves shut when they sense a bug, or something else, moving on them. But they only do this if whatever it is moves twice within about 15–20 seconds.
The movements are sensed by fine ‘trigger’ hairs on the leaves and translated into electrical pulses, carried by waves of charged atoms (ions) flowing through the plant. When an electrical pulse is triggered twice, the leaves snap shut.
But, as a group of international scientists showed in 2016, the botanical fly-baiters are able to tally higher than two.
They wait until they’ve sensed at least three electrical pulses before they start producing the chemicals needed to digest their prey, presumably to avoid wasting their energy on lucky escapees.
Even before this revelation, though, scientists were suggesting that thale cress (Arabidopsis thaliana), an inoffensive cousin to cabbage that’s widely used in plant studies, could do something akin to division.
During the day, plants use sunlight to build up their food stores (starch) via photosynthesis.
But to keep themselves alive at night, they have to set a sustainable rate of starch consumption (starch divided by time) by gauging how much starch they’re storing in their leaves and combining this information with their circadian sense of time.
Experts argue we shouldn’t label these curious counting abilities as ‘intelligent’ or as evidence that plants have some primitive form of brain. They’re just doing what they need to survive. But it’s surprisingly sophisticated.
This article is an answer to the question (asked by Llewi Evans, Monmouthshire) 'Can plants count?'
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