Adjustable valves gave ancient plants the edge
Press release issued: 9 June 2011
Controlling water loss is an important ability for modern land plants as it helps them thrive in changing environments. New research from the University of Bristol, published today in the journal Current Biology, shows that water conserving innovations occurred very early in plants’ evolutionary history.
Elizabeth Ruszala, a Gatsby Charitable Foundation-funded PhD student working in Professor Alistair Hetherington’s research group in the School of Biological Sciences, studied the stomata of Selaginella uncinata, a member of a primitive group of plants called spikemosses, which first appeared approximately 400 million years ago.
Significantly, not only were the stomata of this ancient group of land plants able to open and close in response to changes in light and carbon dioxide, they also responded to the key plant hormone abscisic acid which regulates stomatal function – especially under drought conditions – in modern plants.
These results show that the ability to regulate stomatal aperture in response to changing environmental conditions was already present very early in plant evolution.
Research on understanding how stomata work is also directly relevant to the agriculture needs of the twenty-first century because a key target for crop breeders is the development of new varieties that produce excellent yields but use less water in the process.
Professor Alistair Hetherington said: “Understanding how plants made the successful transition from life in water to the successful colonization of the drying terrestrial environment is one of the big questions in contemporary plant biology. Our work shows that the acquisition of stomata that were able to open and close in response to changing environmental conditions, thereby helping plants to avoid drying out, was a very important step in the evolution of the land flora.”
‘Land plants acquired active stomatal control early in their evolutionary history’ by Elizabeth M. Ruszala, David J. Beerling, Peter J. Franks, Caspar C. Chater, Stuart A. Casson, Julie E. Gray and Alistair M. Hetherington in Current Biology.