It’s a problem that puzzled even geneticist Charles Darwin so much he called it the “abominable mystery” — how did flowering plants take over the world?
They’re relative newcomers, yet they dominate most landscapes, are incredibly diverse, form the basis of our food system and drive the animal diversity we see all around us.
A recent paper in the open-access journal PLOS Biology suggests it’s all about the cell size. Researchers from San Francisco State and Yale universities found flowering plants have small cells when they’re stacked up against other plant types, something that’s made possible by a similarly smaller genome.
It makes it possible to build more and more complex cells in the same space, and makes the cells created more efficient at tasks like photosynthesis. Additionally, by shrinking the size of each cell, water and nutrient delivery can be made more efficient.
Comparing hundreds of species, the researchers found that genome downsizing began about 140 million years ago and coincided with the spread of the earliest flowering plants around the world. “The flowering plants are the most important group of plants on earth, and now we finally know why they have been so successful,” they wrote.
Although this research answers a major question, it opens the door to many more. Why were the flowering plants able to shrink their genomes more than other plant groups? What innovations in genome structure and packing have the flowering plants exploited? How have the ferns and conifers managed to elude extinction despite their large genomes and cells?