Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Exploring the roots of the problem: How a South American tree adapts to volcanic soils

24.01.2014
Low soil nitrogen, not soil phosphorus levels, stimulate cluster root adaptation in the Proteaceae Embothrium coccineum, a tree that may be key to reforestation in Patagonia

Soils of southern South America, including Patagonia, have endured a high frequency of disturbances from volcanic eruptions, earthquakes, landslides, and erosion.


Left, small seedling (ca. 5 mo–old) collected in Reserva Nacional Cerro Castillo, Chile, with its noticeable cluster roots holding soil. Right, one young cluster root; notice that they are simple cluster roots (i.e., bottle-brush-like structures).

Credit: Left by Frida Piper; right by Mabel Delgado.

In addition, massive fires in the mid-20th century were set to forests in the region in an effort to promote colonization. In 2010, another 17,000 acres of Patagonia burned, fueling an international reforestation effort.

Although the young soils of southern South America may contain high phosphorus levels, the element is tightly bound to the soil, offering limited phosphorus available to plants.

So how can plants in this area take root and access that phosphorus?

According to a recent article published in the American Journal of Botany, scientists have identified a mechanism enabling a native tree species access to this limiting nutrient. As a result, the Chilean fire bush (Proteaceae, Embothrium coccineum), a tree endemic to Chile and Argentina, could have an important role in the reforestation of Patagonia.

In the wild, E. coccineum colonizes highly disturbed land where other tree species rarely occur. Proteaceae species, common in the southern hemisphere, are known for a root structure adaptation that increases phosphorus acquisition from weathered, phosphorus-poor soils. The greater surface area of cluster roots increases root exudates of organic acids and phosphatases. These exudates enhance plant phosphorus acquisition from unavailable forms in the soil.

"I was particularly curious of the ecological role of this root adaptation," explained Frida Piper, a terrestrial ecosystem ecologist at the remote research center Centro de Investigación en Ecosistemas de la Patagonia (CIEP) in Coyhaique, Chile. Piper designed a field study to better understand the role of cluster roots of E. coccineum across a natural precipitation and phosphorus gradient in its native habitat. How does the production of cluster roots in this Proteaceae enable successful establishment in young volcanic soils of South America?

Small and large E. coccineum seedlings and topsoil were collected at four sites in the Aysén Region of Patagonia, Chile, in 2010-2013. Seedlings were assessed for number and biomass of cluster roots, plant size and growth, and foliar phosphorus levels. Soil samples were analyzed for pH, total nitrogen (N), available phosphorus (P) and organic matter. Based on biomass and chemical analyses, four dominant factors were identified: soil P, soil N, foliar P, and seedling age. A suite of generalized linear mixed–effect model regressions were fitted to the data.

In contrast to previous studies of Proteaceae in Australia and South Africa, the best-fit model for predicting the number of cluster roots in this study did not contain any soil P factor; foliar P levels correlated with cluster root formation. The number of cluster roots was significantly higher in large seedlings, yet biomass investment in cluster roots was greater for small seedlings.

Piper found that cluster roots mediate a decoupling of foliar P from soil P concentrations for small seedlings. This enabled small seedlings to maintain adequate foliar P levels, critical to their ontogenetic growth. The relative investment in cluster roots was directly linked to both low soil N and leaf P. Seedlings from sites with lower total soil N had more cluster roots, regardless of other soil characteristics. The cluster root adaptation is very sensitive and highly expressed at low total soil N levels but rapidly disappears as soil N levels increase. The investment in cluster roots declines after seedling establishment, most likely as aerial growth is increasingly important for light competition.

Embothrium coccineum may have an important role in reforestation of Patagonia as an early successional species. Cluster roots have been identified in other plant species, including some agronomic crops in the Cucurbitaceae. "The biotechnology potential of these traits is being studied now," Piper says. Piper's research clarifying the mechanism of seedling establishment success for E. coccineum in conditions with limited availability of N and P may lead to advantageous root adaptation in other plants.

Piper is already exploring further research to understand how E. coccineum benefits neighbors by providing increased nutrient availability from root exudates or leaf litter decomposition. As a result of this study, nitrogen status of soil and plants, in addition to phosphorus, will always be included in Proteaceae studies by Piper. "Proteaceae can do something no other plant can do," Piper explains. "They are accessing nutrients that no other plants can access."

Piper, Frida I., Gabriela Baez, Alejandra Zúñiga-Feest, and Alex Fajardo. 2013. Soil nitrogen, and not phosphorus, promotes cluster-root formation in a South American Proteaceae, Embothrium coccineum. American Journal of Botany 100:2328-2338. doi:10.3732/ajb.1300163

The full article in the link mentioned is available for no charge for 30 days following the date of this summary at http://www.amjbot.org/content/100/12/2328.full.pdf+html. After this date, reporters may contact Richard Hund at ajb@botany.org for a copy of the article.

The Botanical Society of America is a non-profit membership society with a mission to promote botany, the field of basic science dealing with the study and inquiry into the form, function, development, diversity, reproduction, evolution, and uses of plants and their interactions within the biosphere. It has published the American Journal of Botany for nearly 100 years. In 2009, the Special Libraries Association named the American Journal of Botany one of the Top 10 Most Influential Journals of the Century in the field of Biology and Medicine.

For further information, please contact the AJB staff at ajb@botany.org.

Richard Hund | EurekAlert!
Further information:
http://www.botany.org

More articles from Life Sciences:

nachricht Scientists enlist engineered protein to battle the MERS virus
22.05.2017 | University of Toronto

nachricht Insight into enzyme's 3-D structure could cut biofuel costs
19.05.2017 | DOE/Los Alamos National Laboratory

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

Im Focus: Hydrogen Bonds Directly Detected for the First Time

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

Media accreditation opens for historic year at European Health Forum Gastein

16.05.2017 | Event News

 
Latest News

New approach to revolutionize the production of molecular hydrogen

22.05.2017 | Materials Sciences

Scientists enlist engineered protein to battle the MERS virus

22.05.2017 | Life Sciences

Experts explain origins of topographic relief on Earth, Mars and Titan

22.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>