“Plant evolution can happen in a few decades” – Editorial

launchPartner of the “What is life?” Organized by the Cité des sciences et de l’industrie, it will regularly feature articles, interviews and forums on the topics discussed. to follow up immediately or live on YouTube, “Plant Reproduction Strategies” conference by Pierre-Olivier Chepteau, ecologist and evolutionist, on Tuesday, March 14th at 6:30 p.m.

Different flowers, less mobile seeds, hermaphroditic plants … Pierre-Olivier Chepteau, Director of Research at the National Center for Scientific Research and the Center for Functional and Evolutionary Ecology, tells us how plants adapt to the changes taking place, in particular to reproduction.

What changes do the plants you study experience?

I mainly work in anthropogenic environments, that is, modified by human activities, in cities or in agricultural settings. For example, I studied Think fieldsa familiar little flower of rapeseed crops in the Paris region, or Krebs sancta (a type of dandelion), these very common small yellow flowers, or cornflowers. These species face global warming but also face pollinator decline.

How do you go about studying the evolution of these plants?

To compare today’s plants to plants of the past, we work from seed. In France, in the 1980s, the Botanical Institutes took the initiative to preserve the seeds so that they could be reintroduced if necessary. We use it to study climate adaptation. It’s called a “resurrection environment,” though I don’t like that term very much. So we grow these ancient seeds next to the current seeds in similar conditions and environment. We can see the developments and compare the characteristics of yesterday to those of the present.

What are the notable differences between yesterday’s plants and today’s plants?

We find that flowering occurs earlier and that the flowers have changed in size. They have different botanical traits, and this is no doubt related to the decline of pollinators. Another major development is self-fertilization. Most plants are generally hermaphrodites: they have the ability to self-fertilize and with less feed, they use it more. In another record, their method of seed dispersal also evolved. We have noticed that in the city, weeds and weeds produce more large seeds that do not move than small ones that fly away. Spreading its seeds in a fragmented urban environment is risky. Better to leave it where it is.

This adaptability might sound like good news?

Indeed, this is a worrying result, because if the interaction between plants and pollinators is broken, the functioning of the ecosystem will be disrupted. If the plants do without insects, the latter will have nothing left to eat while they themselves feed the birds. This can cause a cascading effect. Previously, according to Darwin’s ideas, scientists believed that these processes were slow and tangible over thousands of years, but we realize that these developments can occur much faster, within a few decades.