2023-06-15 08:00:16
In a series of experiments, Professor Michael Knoblauch and colleagues at Washington State University showed that individual plant cells respond to contact with a very thin glass rod by sending slow waves of signals to d other plant cells.
And when the pressure is released, they send out much faster waves
explain the researchers in a press release published by the institution.
Plants have previously been shown to respond to touch, but the present work indicates that plant cells send different signals at the start and end of a touch.
« It is quite surprising how sensitive plant cells are, that is, they are able to determine if something is touching them. They sense the pressure, and when the object is released, they sense the drop in pressure. »
Plants are sentient in a very different way from animals, without nerve cells and at a very fine level
continues Professor Knoblauch.
The American team carried out a series of 84 experiments using the so-called microlever technique applied to individual cells of the epidermis of intact leaves from 12Arabidopsis thaliana and of Nicotiana tabacum. Their leaves synthesized genetically modified calcium indicators.
These experiments revealed that compressive forces induce calcium peaks that precede slow-moving, delayed calcium waves. Releasing the force causes noticeably faster waves
note the researchers in the study.
In addition, the scientists observed many complex responses depending on the strength and duration of the touch, and the difference between the start and the end of the touch was always very clear.
In more detail, within 30 seconds of a cell beginning to touch, the researchers observed slow waves of calcium ions traveling from the cell to its neighbors for about three to five minutes. Upon breaking contact, they saw an almost instantaneous series of faster waves that dissipated within a minute.
These waves are probably due to the change in pressure inside the cell. Unlike animal cells whose membranes are permeable, plant cells also have strong cell walls that cannot be easily breached, so a simple light touch temporarily increases the pressure in a plant cell.
explain the researchers.
« Humans and animals perceive touch through sensory cells. In plants, the mechanism seems to go through the increase or decrease of the internal pressure of the cell. And it doesn’t matter which cell it is. We humans may need nerve cells, but in plants any cell on the surface can. »
Other work has shown in the past that when a pest, such as a caterpillar, bites a plant leaf, it can trigger plant defense responses, such as the release of chemicals that make the leaves less palatable, or even toxic to the pest. Another study also revealed that brushing a plant triggers calcium waves that activate different genes.
Future studies may attempt to trigger the signal different from what has been done so far to find out which signal, if touched or dropped, triggers downstream reactions.
A study published in April showed that plants emit sounds, especially when under stress, according to the work of Israeli scientists. These sounds inaudible to the human ear would however be perceptible by other plants as well as by some species of mammals and insects.
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