Basically about drought resistance – looks like “climate change” is in the title to get some attention
New research by UCLA life scientists could lead to predictions of which plant species will escape extinction from climate change.
Droughts are worsening around the world, posing a great challenge to plants in all ecosystems, said Lawren Sack, a UCLA professor of ecology and evolutionary biology and senior author of the research. Scientists have debated for more than a century how to predict which species are most vulnerable.
Sack and two members of his laboratory have made a fundamental discovery that resolves this debate and allows for the prediction of how diverse plant species and vegetation types worldwide will tolerate drought, which is critical given the threats posed by climate change, he said.
The research is currently available in the online edition of Ecology Letters, a prestigious ecology journal, and will be published in an upcoming print edition.
Why does a sunflower wilt and dessicate quickly when the soil dries, while the native chaparral shrubs of California survive long dry seasons with their evergreen leaves? Since there are many mechanisms involved in determining the drought tolerance of plants, there has been vigorous debate among plant scientists over which trait is most important. The UCLA team, funded by the National Science Foundation, focused on a trait called “turgor loss point, which had never before been proven to predict drought tolerance across plant species and ecosystems.
A fundamental difference between plants and animals is that plant cells are enclosed by cell walls while animal cells are not. To keep their cells functional, plants depend on “turgor pressure” — pressure produced in cells by internal salty water pushing against and holding up the cell walls. When leaves open their pores, or stomata, to capture carbon dioxide for photosynthesis, they lose a considerable amount of this water to evaporation. This dehydrates the cells, inducing a loss of pressure.
During drought, the cell’s water becomes harder to replace. The turgor loss point is reached when leaf cells get to a point at which their walls become flaccid; this cell-level loss of turgor causes the leaf to become limp and wilted, and the plant cannot grow, Sack said.