The world is a cooler, wetter place because of flowering plants, according to new climate simulation results published in the journal Proceedings of the Royal Society B. The effect is especially pronounced in the Amazon basin, where replacing flowering plants with non-flowering varieties would result in an 80 percent decrease in the area covered by ever-wet rainforest.
The simulations demonstrate the importance of flowering-plant physiology to climate regulation in ever-wet rainforest, regions where the dry season is short or non-existent, and where biodiversity is greatest.
"The vein density of leaves within the flowering plants is much, much higher than all other plants," said the study's lead author, C. Kevin Boyce, Associate Professor in Geophysical Sciences at the University of Chicago. "That actually matters physiologically for both taking in carbon dioxide from the atmosphere for photosynthesis and also the loss of water, which is transpiration. The two necessarily go together. You can't take in CO2 without losing water."
This higher vein density in the leaves means that flowering plants are highly efficient at transpiring water from the soil back into the sky, where it can return to Earth as rain.
"That whole recycling process is dependent upon transpiration, and transpiration would have been much, much lower in the absence of flowering plants," Boyce said. "We can know that because no leaves throughout the fossil record approach the vein densities seen in flowering plant leaves."
For most of biological history there were no flowering plantsknown scientifically as angiosperms. They evolved about 120 million years ago, during the Cretaceous Period, and took another 20 million years to become prevalent. Flowering species were latecomers to the world of vascular plants, a group that includes ferns, club mosses and confers. But angiosperms now enjoy a position of world domination among plants.
|Contact: Steve Koppes|
University of Chicago