They discover the first plant that fell asleep

Many plants close their leaves at night.

Image – Flickr/Joegoauk Goa

Some plants fold their leaves at night, and they don’t do this because they are sick, but as a means of survival to avoid too much damage from active insects when the sun goes down. This movement is known as leaf nyctinasty, although it also receives another one that is easier to remember: sleep movements.

It’s not something new, it’s not something that has been discovered now. But what is new is to discover when did the plants begin to fall asleep. And that’s about 250 million years ago, neither more nor less.

How could they know? This is the first thing you might wonder, because of course the leaves decompose quickly, and it is therefore very difficult to keep them for long unless the conditions are right for them to fossilize. And even so, it is even more complicated to know if these sheets were folded to “sleep”, or simply because they were reaching the end of their life.

Also. An international team of scientists succeeded. For that, what they did was look at the insect damage on the leaves, and what they discovered is truly amazing. See:

leaf damaged by insects

Image – Cell.com // Fossilized leaf of a giganthopterid plant.

This symmetrical damage, which could only be caused by insects when the leaf was bent. Now compare this image to these modern plant leaves:

Leaves show symmetrical damage

Picture – Cell.com. (BC) Arachis duranensis Krapov. and Greg.(D) Bauhinia variegata var. candidiasis (Aiton) Voigt.(E) acuminate bauhinia linn.

They’re pretty much the same, right? And it is that they happened in the same circumstances: at night, when the leaves were folded. The finding was published in the journal Current Biology.

The plants studied were giganthopterids, a group of plants that lived during the late Paleozoic. in a microcontinent which is today China, and which they call Catasya. Also, they weren’t happy with it, but wanted to look for evidence that it was still happening. And that’s why they studied modern plants that also had leaf nyctinastia, like albizia or bauhinia.

This is how they learned that giganthopterids were attacked by insects while they slept.

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