Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Is that plant a tortoise or a hare? Answer predicts its response to environmental change

22.04.2004


As the spring foliage grows, each plant, like an entrepreneur, builds its leaves according to an economic strategy. Some plants live like the proverbial hare, following a "live fast, die young" strategy; their leaves produce and consume energy quickly but soon "burn out" or fall victim to bad weather or hungry herbivores. Other leaves are more tortoiselike, taking a "live slowly and last long" approach. A new study has revealed the global continuum of leaf economics, documenting where 2,548 species growing at 175 sites fit along the "tortoise-hare" continuum. For the first time, scientists can equate plants in Amazonian rain forest, Minnesota prairie or Alaskan spruce woods using the same set of economic strategies. Moreover, a plant’s position on the continuum predicts how it will likely respond to climate change and other factors. The work will be published in the April 22 issue of the journal Nature.



"This is the most comprehensive study of the physiology of natural vegetation ever done," said author Peter Reich, professor of forest resources at the University of Minnesota. "Leaves are little factories. As a factory, each can make money (energy) in a big hurry, but at the risk of running down its equipment fast. Or, a factory can have a slow and steady output. It’s fundamental tradeoff for every leaf, and the strategy it follows determines how it reacts to change." Besides Reich, authors of the paper were Ian Wright (first author) and Mark Westoby of Macquarie University, Australia, Jeannine Cavender-Bares and Jacek Oleksyn from the University of Minnesota, and a long list of researchers from every inhabited continent.

It all began in 1985, when Reich was a postdoctoral fellow at Cornell University. He compared the rates different plants captured and stored energy through photosynthesis and the rates they used energy--a process called respiration. He noticed that two fast-growing "hare" plants--poplar trees and soybeans--were more susceptible to ozone pollution than slower-growing "tortoise" pine trees.


"It’s because poplar trees exchanges gases faster than pine," said Reich. "Therefore, poplar takes in more ozone than pine. Soybeans, wheat and other crops are bred to grow fast, and they tend to be like poplars. This was an important predictor of how these trees and crops would respond to pollution. I wondered how they had come to have these traits in the first place and what the implications were for responses to changes in environment more broadly. So I began to physiologically compare plants whose leaves might have these contrasting economic strategies. I’ve carried portable photosynthesis sensors to more than 20 sites on four continents."

Twenty years later, Reich and his colleagues can say that plants like hares and tortoises are found in every ecosystem, and so plants from boreal forest, rainforest, desert and everywhere else can be compared. For example, "hares" like aspen and birch are better able to use resources when conditions get better. Therefore, if rainfall or nutrient levels increased, these trees would do well. But if conditions were to get drier or less fertile, the slower-growing "tortoises"--such as spruce, hemlock and other evergreens--would be favored, he said. Similarly, if there is little sunlight available in the understory of a forest, the "tortoises" can scale back their operations and live with it. In general, "hares" are good at "ramping up" when conditions improve, but tortoises are better at controlling their energy consumption when times get tough. Thus, the theory works well as a predictor of responses to increasing nitrogen pollution, added Reich.

The researchers also noted that leaves are built in accordance with their economic strategy. Leaves of fast-growing plants tend to be thin and flimsy and full of expensive nutrients like nitrogen and phosphorus. The thinner a leaf, the better the chance that a ray of sunlight will penetrate to the leaf’s photosynthetic machinery--but the greater its chance of being blown or chomped off. And the expensive invesstments in nutrients only pay off when there is a lot of sunlight and conditions are generally good. In contrast, slow growth allows for thick, sturdy leaves that resist weather and herbivores and can pay off under challenging conditions.

Weeds usually fall into the hare category, said Reich. Their strategy is to grow fast and quickly release seeds, and they tend to grow in places where the vegetation is disturbed.

Data for the study were collected from the University of Minnesota’s Cedar Creek Natural History Area, forests in Wisconsin and Minnesota, the New Mexican desert, the Appalachian Mountains, the Amazon Basin, the Australian Outback and numerous other places. The work was supported in part by the National Science Foundation and the U.S. Department of Energy.

Deane Morrison | EurekAlert!
Further information:
http://www.umn.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Robotic fish to replace animal testing
17.06.2019 | Otto-von-Guericke-Universität Magdeburg

nachricht Marine oil snow
12.06.2019 | University of Delaware

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: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Novel communications architecture for future ultra-high speed wireless networks

17.06.2019 | Information Technology

Climate Change in West Africa

17.06.2019 | Earth Sciences

Robotic fish to replace animal testing

17.06.2019 | Ecology, The Environment and Conservation

VideoLinks
Science & Research
Overview of more VideoLinks >>>