The dominance of the flowering plant
3 Dec 2009 by Evoluted New Media
Flowering plants gained an evolutionary advantage over rivals but how?
Flowering plants gained an evolutionary advantage over rivals but how?
Flowring plants and crops gained a competitive advantage over rival species by developing an efficient hydraulic system to increase their rate of photosynthesis and chances of survival.
Dr Tim Brodribb from the School of Plant Science at the University of Tasmania and Dr Taylor Field from the University of Tennessee used measurements of leaf vein density and a linked hydraulic model to reconstruct the evolution of leaf hydraulic capacity in seed plants.
“Flowering plants are the most abundant and ecologically successful group of plants on earth,” Brodribb said, “One reason for this dominance is the relative photosynthetic capacity of their leaves, but when and how this increased photosynthetic capacity evolved was unknown.”
Brodribb and Field’s results showed an evolutionary transformation in the plumbing of angiosperm leaves increased their photosynthetic capacity. Under the relatively low atmospheric carbon dioxide conditions, water transport efficiency and photosynthetic performance are closely linked, so any adaptation to increase water transport will aid photosynthesis and give the plant a competitive edge.
This evolutionary step - around 100-140 million years ago - was of importance for the continued evolution of flowering plants. It provided a ‘cretaceous productivity stimulus package’ that echoed across the biosphere and led to plants playing a fundamental role in the atmospheric and biological functions of the earth.
“Without this hydraulic system we predict leaf photosynthesis would be two-fold lower than present, so it is significant to note that without this evolutionary step land plants would not have physical capacity to drive the high productivity that underpins modern terrestrial biology and human civilisation,” Bodribb said.
