Flowering plants make the world a cooler, wetter place, says research. The effect is especially pronounced in the Amazon basin where flowering plants replaced with non-flowering plants would result in an 80 per cent decrease in the area covered by wet rainforest.
“The vein density of leaves in flowering plants is much higher than all other plants. That results in absorption of more carbon dioxide (CO2) from the atmosphere for photosynthesis. This further result in more loss of water vapours from the plant. You can’t take in CO2 without losing water,” said the study’s lead author, C. Kevin Boyce, associate professor in geophysical sciences at the University of Chicago.
This makes the flowering plants highly efficient at transpiring water from the soil back into the sky, where it can return to Earth as rain.
“The whole recycling process is dependent upon transpiration, and transpiration would have been much lower in the absence of flowering plants. We can know that because no leaves throughout the fossil record approach the vein densities seen in flowering plant leaves,” Boyce added.
For most of biological history there were no flowering plants known. They evolved about 120 million years ago, during the Cretaceous Period.
Dinosaurs walked the Earth when flowering plants evolved, and various studies have attempted to link the extinction of dinosaurs or at least their evolutionary paths to flowering plant evolution. “Those efforts are always very fuzzy, and none have gained much traction,” Boyce said.
