In May 2016, experts from the Royal Botanic Gardens at Kew in London released a detailed report on the state of plants in the world. In it they indicated that, at present, of the 391,000 known vascular plant species – in that same note they warned that 21% are threatened or in danger of extinction , although 2,000 more are described each year – some 369,000 show flowers , some characteristic reproductive structures that adopt different shapes and tonalities.
Despite their great diversity, flowers are a relatively recent evolutionary innovation, at least on a geological scale . This is indicated by an international team of researchers in a new study published in the journal Nature Communications , where they point out that their most recent common ancestor must have existed between 250 and 140 million years ago . However, the oldest fossils of them that have been discovered to date are no more than 130 million years old.
A comprehensive study
In the same work, these scientists, coordinated by Hervé Sauquet, a botanist and evolutionary biologist who works at the Laboratory of Ecology, Systematics and Evolution of the University of Paris-Sur, in France, show for the first time the possible characteristics of what would be that ancestor of all flowering plants: a specimen that already had male and female organs – in the model they have built, it is estimated that it would have more than six stamens and five or more carpels, respectively – as well as several groups of tepals – these they function as sepals and petals – arranged in concentric rings. Until now, it was thought that in the most primitive flowers, these structures used to be arranged in spirals.
To determine this, they examined 21 distinctive floral traits in 792 species of angiosperms – that is, plants that have flowers -, from the position of the ovaries to the relationship that exists between the different families to which they belong. To establish this association they had to carry out a careful study of the fossil record.
Much to discover
In the recreation that Sauquet and his collaborators have presented the appearance of this first floral species, from which all the others descend , it presents a certain similarity to that of some magnolias, but, although there are currently plants similar to it, the researchers They note that none of them retain exactly the same peculiarities.
These scientists also admit that our knowledge about the origin of flowers still has many obscure points , such as, for example, how the mechanisms that promoted their great diversification originated or why some species lost their stamens. In fact, the available data does not allow us to know the exact color, size or shape of the floral ancestor that they have now described. Not even in what area of the world could it grow. Even so, his research constitutes one of the most accurate approximations to the evolution of angiosperm plants and will serve to promote new studies on these organisms.
Bibliographic reference: H. Sauquet et al. “The ancestral flower of angiosperms and its early diversification”. Nature Communications, August 1, 2017. DOI: 10.1038 / ncomms16047
Image: Hervé Sauquet & Jürg Schönenberger
