Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Plants have little wiggle room to survive drought, UCLA life scientists report

14.11.2014

Plants all over the world are more sensitive to drought than many experts realized, according to a new study by scientists at UCLA and China's Xishuangbanna Tropical Botanical Garden.

The research will improve predictions of which plant species will survive the increasingly intense droughts associated with global climate change.


Researchers measured leaves' drought tolerance at the "turgor loss point" -- the level of dehydration that causes them to wilt.

Credit: Lawren Sack

The research is reported online by Ecology Letters, the most prestigious journal in the field of ecology, and will be published in an upcoming print edition.

Predicting how plants will respond to climate change is crucial for their conservation. But good predictions require an understanding of plants' ability to acclimate to environmental changes, or their "plasticity." All organisms show some degree of plasticity, but because they're stationary, plants are especially dependent on this ability.

"Plants are masters of plasticity, changing their size, branching patterns, leaf colors and even their internal biochemistry to adjust to changes in climate," said Lawren Sack, a professor of ecology and evolutionary biology in the UCLA College and the study's senior author.

Little has been known about the degree to which plastic changes might allow plants to endure worsening droughts.

"Plants have evolved this amazing ability to sync with their environment, but they are facing their limits," said Megan Bartlett, a UCLA doctoral student in ecology and evolutionary biology and the study's lead author.

Compiling and analyzing data for numerous species from various ecosystems around the world, Bartlett found that most species accumulate salts in their cell sap to fine-tune their tolerance to seasonal changes in rainfall. But that adjustment only provides a relatively narrow degree of additional drought tolerance.

Saltier cell sap gives plants the ability to continue to grow as soil dries during drought. Unlike animal cells, plant cells are enclosed by cell walls. To hold up the cell walls, plants depend on "turgor pressure" -- the pressure produced by internal water pushing against the inside of the cell wall. As the cells dehydrate, the turgor pressure declines until the cell walls collapse, and the leaf becomes limp and wilted.

The team of biologists collected data on the "turgor loss point" -- the level of dehydration that causes leaves to wilt. Plants that have a lower turgor loss point can lose more water before wilting, and can keep open their pores, or stomata, to take up carbon dioxide for photosynthesis in drier soils.

"During a drought, plants have to choose between closing their stomata and risking starvation, and continuing to photosynthesize and risking cell damage from wilting," Sack said.

Previous research by the UCLA team revealed the key mechanism plants use to adjust their turgor loss point during drought. Plants load their cells with salts, which attract water molecules and limit turgor loss. In wet conditions, plants invest fewer resources in producing and accumulating these solutes and reduce the saltiness of their cell sap.

Drawing on both new data they produced and previously reported data for hundreds of species, the scientists determined the overall picture of how much plant species adjust their cell sap saltiness to maintain turgor and continue to grow during drought.

"For most plants, these adjustments were small," Sack said. "This means they have only limited wiggle room as droughts become more serious. On the plus side, this discovery means we can estimate species' drought tolerance relatively simply. We can make a reasonable drought tolerance measurement for most species regardless of time of year or whether we are sampling during wet or dry conditions."

Bartlett said the finding is good news for plant biologists. "It means that predicting how a species will respond to climate change from one season of drought tolerance measurements is a reasonable place to start," she said. "Our predictions will be more accurate when we take plasticity into account, but sampling in one season is a reasonable simplification for really diverse ecosystems, like tropical rainforests."

All ecosystems potentially vulnerable

The researchers expected plants' plasticity to be very different based on whether they live in deserts, which may get less than an inch of rainfall per year, or rainforests, which may receive more than 10 feet. Instead, they found relatively small differences across ecosystems, meaning that plants are potentially vulnerable no matter where they live, the scientists said.

The researchers also compared plasticity for crops. They found a strikingly contrasting result: Whereas differences in plasticity among wild species were relatively small and unimportant, among the varieties of certain crop species -- such as coffee and corn -- greater plasticity resulted in improved drought tolerance.

"It's been suspected for a long time that plasticity in cell saltiness might improve crop drought tolerance, so it makes sense that we found impressive differences among crop cultivars and that these differences translate into drought tolerance," Bartlett said. "Our study points to plasticity in turgor loss point as an especially important focus for breeding and selecting drought tolerant cultivars."

The research was funded by the National Science Foundation's Graduate Research Fellowship Program and East Asia and Pacific Summer Institute, the Smithsonian Institution's Center for Tropical Forest Science - Forest Global Earth Observatory, the Vavra Research Fellowship and UCLA's department of ecology and evolutionary biology.

Stuart Wolpert | EurekAlert!
Further information:
http://www.newsroom.ucla.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

nachricht Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

UCLA engineers use deep learning to reconstruct holograms and improve optical microscopy

22.11.2017 | Medical Engineering

Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells

22.11.2017 | Materials Sciences

New study points the way to therapy for rare cancer that targets the young

22.11.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>