Plants react to anaesthetics: Are they ideal subjects for testing new substances?

The carnivorous Venus flytrap detects its prey by means of electrical signals made by the bending of its trigger hairs. The presence of anaesthetics makes them – as well as the rapid leaf movement – completely immobilised. After the anaesthetics are removed, the Venus flytrap begins to perceive the surrounding world and recovers its electrical activity.
Photo: Andrej Pavlovič
friday 16. february 2018, 13:53 – Text: Martina Šaradínová

Anaesthetics used in human and veterinary medicine have a very similar effect on plants. This has been confirmed in a study by an international scientific team, whose only Czech member was biophysicist Andrej Pavlovič from the Centre of the Region Haná for Biotechnological and Agricultural Research. Thanks to their findings, recently published in a prestigious journal Annals of Botany, plants could be used in the future for instant testing of substances with anaesthetic effects. 

Researchers from Japan, Germany, Italy, and the Czech Republic verified the effects of anaesthetics on the model plant thale cress (Arabidopsis thaliana L.), as well as other species that show movement – for instance, the touch-me-not (Mimosa pudica L.) responsive to touch stimuli, the Venus flytrap (Dionaea muscipula Ellis) that closes its leaf trap, or the pea (Pisum sativum L.) with its tendrils.

“We tested several types of anaesthetics with various chemical structures and we have found out that the action of anaesthetics on plants is similar to that on animals or humans. Under their influence, the plants de facto stop perceiving their environment; however these effects are not irreversible. Once the anaesthetic is removed, the effects subside. The finding could have practical applications, as plants could be used in the future for rapid screening of anaesthetic effects of various substances,” said Pavlovič.

According to him, anaesthetics can even stop plant movements. After exposure to them, Venus flytraps do not close their trap, Mimosa plants are not responsive to touch stimuli, and climbing plants stop looking for an object to lean against. They also impede seed germination and chlorophyll synthesis. “This behaviour seems strange since we know that plants have no nervous system to be affected by anaesthetics. However, plants generate electrical signals, and these are affected by anaesthesia. Similarly to animals, plants temporarily ‘lose consciousness’. Once the anaesthetic compounds are removed, the plants rapidly recover, and their electrical signalling returns to normal. The changes of electrical potential on the plant membranes are often the first signal that the plant perceives the world around,” explained Pavlovič, who conducted part of the experiments in the Olomouc research centre.

Scientists have arrived at the conclusion that anaesthetics may have a similar mechanism of effect that probably targets the cell membranes. Anaesthetics are likely to interfere with them, as it is indicated by the fact that anaesthetics inhibit the recycling of vesicles, i.e. membrane-enclosed pouches that store and transport some of the more complex organic substances.

“Similar effects of anaesthetics on plants as well as animals have been reported, but the mechanism was unclear. We have shown that anaesthetics inhibit electrical signals in the plant, therefore their ‘nervous’ activity is put to sleep. It is the first work of its kind,” added Pavlovič. The article has been reported on by foreign media.

The Centre of the Region Haná where Pavlovič is employed is a joint facility of research teams from the Palacký University Faculty of Science and the Olomouc branches of the Institute of Experimental Botany at the Czech Academy of Sciences and the Crop Research Institute.