New research makes possible rapid assessment of plant drought tolerance

UCLA Newsroom: UCLA life scientists, working with colleagues in China, have discovered a new method to quickly assess plants’ drought tolerance. The method works for many diverse species growing around the world. The research, published in the journal Methods in Ecology and Evolution, may revolutionize the ability to survey plant species for their ability to withstand drought, said senior author Lawren Sack, a UCLA professor of ecology and evolutionary biology.

"This method can be applied rapidly and reliably for diverse species across ecosystems worldwide," he said of the federally funded research by the National Science Foundation. ... Earlier this year, Sack and his research team resolved a decades-old debate about what leaf traits best predict drought tolerance for diverse plant species worldwide. However, these leaf traits are too difficult and time-consuming to measure, often taking up to two days for one species, Sack said.

The UCLA team worked with collaborators at the Xishuangbanna Tropical Botanical Gardens (XTBG) in Yunnan, China, to develop a method for measuring leaf drought tolerance that is 30 times faster. It is based on an important trait known as "turgor loss point." During drought, the leaf cells’ water becomes harder to replace. The turgor loss point is reached when leaf cells become so dehydrated their walls become flaccid. This cell-level loss of turgor — or swollenness — causes the leaf to become limp and wilted, and the plant cannot grow, Sack said.

The new method, based on a technique called "osmometry," requires only about 10 minutes per leaf, sufficient to make a fast estimate for a given species.

...The turgor loss point, which varies widely among species, is a powerful determinant of the plant’s drought tolerance. The UCLA team previously showed that the turgor loss point can predict the dryness of the ecosystem from which a plant species comes....

In biology, turgor pressure or turgidity is the pressure of the cell contents against the cell wall, in plant cells, determined by the water content of the vacuole, resulting from osmotic pressure. Image by LadyofHats, public domain