The disgusting secret of flowers deciphered on France 5

These beauty queens of the plant world have dazzlingly conquered the planet. On Thursday, May 19, paleontologists, biologists and geneticists come together on France 5 to explain the remarkable phenomenon of evolution that worried Charles Darwin.

Flowers laugh at ice, desert and blizzard. What is the secret of their resilience? Today, flowers make up 90% of the plants on Earth, and a single family of orchids includes more species than all mammals and birds combined. Quite impressively, the sudden diversity of flowering plants had long seemed to contradict Darwin’s theory of evolution based on gradual and slow stages, who, not knowing where to place them on the tree of life, spoke of the disgusting mysterious flowers whose name was chosen for them. this excellent documentary by François Tribole and Clément Champiat, broadcast on France 5 on Thursday 9 May at 21:00. Freely adapted from The Secret History of FlowersA film by geneticist François Parcy (Humensciences/Humensis) explains recent scientific discoveries in the company of Sarah Darwin, botanist and great-great-granddaughter of Charles Darwin. The Hideous Mystery of the Flowers follows a fascinating investigation from one country to another.

Flower, extraordinary genitals

Superblooming or superblooming for days in South Africa’s driest desert is in itself illustrative of this spectacular abundance of flowers in the most unexpected places. A flower, the reproductive apparatus of which has male and female organs of the same structure, is characteristic of plants called angiosperms. They represent a major evolutionary leap from the plants that previously dominated the world. The ancestors of flowering plants, the gymnosperms, have separate reproductive organs, the pollen of which is carried by the wind. There are 300,000 angiosperms for every 1,000 gymnosperms, the documentary explains. The latter are favored by the work of pollinating insects, which deposit and transfer pollen at the same time, allowing genetic mixing in a single visit.

Blue color attracts insects faster

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The documentary explores the seductive power of flowering plants that goes far beyond their irresistible beauty. Their color is the main signal sent to pollinators to charm them. By playing with light, some colors manage to create a blue color due to iridescence – an optical phenomenon of light diffraction, which can be observed on a CD or a soap bubble. The flower has a “structural defect” due to the undulations creating a blue halo. With a stopwatch in hand, scientists are discovering that insects spot a blue flower three times faster. Others produce colors invisible to the human eye, only insects are able to see the bright ultraviolet from their stamens. Flowers also adapt their fragrance to pollinators. Some of them are poisonous, like the titanium arum, the titanic phallus, or the corpse flower. This inflorescence (a cluster of several flowers) has another incredible characteristic: it releases heat to enhance the scent that rises in Indonesia’s lush vegetation, attracting rotting meat-loving insects.

Petals, auditory organs of a flower?

In Israel, the scientist received confirmation of his intuition: plants “hear”! To the sound of a bee broadcast by a speaker, the flower responds by producing 20% ​​more sugar in its nectar, which is the highest reward for a pollinating insect. The laser vibrometer also shows that the petals begin to vibrate as the buzzing insects approach, like small parabolas capable of sensing and capturing the world around them.

Flowers on Earth, 214 million years BC

In the beginning, there was algae in the ocean, which turned into foam in 450 million years BC. The stem and fern appeared about 400 million years ago, and gymnosperms – 300 million years ago. The oldest flower in the world, trichopod amborella, was the subject of a 2014 study that brought together 50 researchers from around the world to decipher its complete genome. Since then, a new study has further pushed back the date of the appearance of flowers on Earth to 214 million years BC. A researcher in evolutionary botany studied a rapidly reproducing plant colonized by two different insects in two separate greenhouses. The result in just nine generations shows a glaring difference in evolution and even the beginning of speciation, the creation of a new species. Another factor that accelerates evolution was discovered when studying the genome of flowers, which contribute to the emergence of numerous mutations. The creative frenzy of flowering plants comes from polyploidization, when a species is able to make copies of its chromosomes. This allows testing of new features (such as cold adaptation) while maintaining a backup copy of the original genome. If the new features give an advantage to the species, then the mutant gene takes precedence over the original gene.

Incredible seed persistence

Unlike dinosaurs, flowering plants survived a 12-kilometer-diameter asteroid impact at over 70,000 km/h, releasing a shockwave equivalent to 5 billion nuclear bombs. 66 million years ago, when intense dust blocked the sun’s rays, preventing photosynthesis, flowering plants survived as seeds in the ground, protected by their hard shell. The second shell, the endosperm, provides nutrients to the plant embryo and controls germination. If the latter is unfavorable, the seed goes dormant. During this time, 75% of species have disappeared on our planet. Thus the seed is the true treasure of evolution.

But to fully explain the rapid evolution of flowering plants, there is another mystery unraveled in the France 5 documentary. François Parcy, a geneticist at the CNRS Laboratory of Cellular and Plant Physiology, discovered the origin of bisexual flowering plants by studying the molecular design of an amazing plant, welwitschia mirabilis, a gymnosperm. which forever reconciles flowers with Darwin’s theory of evolution…

Having reached the top of the plant kingdom, flowers may have found a new type of pollinator in humans! China is currently experimenting with growing flowering plants on the Moon, and NASA plans to grow them on Mars. rose from The little Prince Reminds me of de Saint-Exupéry…

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