Venus flytraps
Anesthetics can temporarily cause plants to go still and unresponsive.Creative Commons

Anesthetics that have become an integral part of medical systems around the world are currently tested on animals, raising serious ethical questions over the practice. But, a new study could potentially change this scenario as it has revealed that plants can succumb to the effects of general anesthetic drugs just like humans and animals.

While it's too early to determine whether the latest findings can put an end to animal testing of such drugs, the study, published in the journal Annals of Botany, is expected to better understand how general anesthetics work on humans. The study results are striking especially because scientists are still unclear about physiological effects of anesthetic drugs on our nervous system.

As part of the study, led by Italian and German plant biologists, the researchers used Mimosa leaves, pea tendrils, Venus flytraps and sundew traps. When Venus flytraps were exposed to diethyl ether anesthesia, their spiky traps stayed open even when their trigger hairs were poked.

The same concentration of diethyl ether immobilised pea tendrils while shy Mimosa leaves stayed open when gently brushed, and the sundew plants didn't bend to capture dead fruit flies.

"Anesthetics also impeded seed germination and chlorophyll accumulation in cress seedlings. Endocytic vesicle recycling and reactive oxygen species (ROS) balance, as observed in intact Arabidopsis root apex cells, were also affected by all anesthetics tested," researchers said.

In all the plant species tested, the anesthetic drug caused the plant to lose both their autonomous and touch-induced movements, according to the researchers.

The researchers exposed the plants to different general anesthetics in different ways to prove that their sensitivity to several drugs with no structural similarities. Some of the pants were enclosed in chambers where they were surrounded by diethyl ether vapor or xenon gas while others had their roots washed before being exposed to lidocaine.

Mimosa leaves
Plants react to anesthetics the same way that humans and animals do.Creative Commons

To observe the effects of anesthetics in the plants, the researchers used three main tools: a single-lens reflex camera to follow organ movements in plants throughout the study, confocal microscopy to analyse the movement of materials between cells, and a surface silver chrlodie electrode to record electrical signals.

The findings helped the researchers come to the conclusion that plants do react to anesthetics the same way that humans and animals do. According to them, the action of anesthetic at cellular and organ levels are similar in humans, animals and plants.

"Plants emerge as ideal model objects to study general questions related to anesthesia, as well as to serve as a suitable test system for human anesthesia," the researchers said.