Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Insects Take A Biger Bite Out Of Plants In A Higher CO2 Atmosphere

25.03.2008
Atmospheric carbon dioxide levels are rising at an alarming rate, and new research indicates that soybean plant defenses go down as CO2 goes up. Elevated CO2 impairs a key component of the plant’s defenses against leaf-eating insects, according to the report.

The University of Illinois study appears this week online in the Proceedings of the National Academy of Sciences.

Deforestation and the burning of fossil fuels have significantly increased carbon dioxide levels since the late 18th century, said plant biology professor and department head Evan DeLucia, an author of the study.

“Currently, CO2 in the atmosphere is about 380 parts per million,” DeLucia said. “At the beginning of the Industrial Revolution it was 280 parts per million, and it had been there for at least 600,000 years – probably several million years before that.”

... more about:
»CO2 »DeLucia »Soy »carbon dioxide »plot »produce »soybean

Current predictions are that atmospheric carbon dioxide will reach 550 parts per million by the year 2050, DeLucia said, and the rapid industrialization of India and China may even accelerate that timetable.

The new study, led by entomology professor and department head May Berenbaum, used the Soybean Free Air Concentration Enrichment (Soy FACE) facility at Illinois. This open-air research lab can expose the plants in a soybean field to a variety of atmospheric CO2 and ozone levels – without isolating the plants from other environmental influences, such as rainfall, sunlight and insects.

High atmospheric carbon dioxide is known to accelerate the rate of photosynthesis. It also increases the proportion of carbohydrates relative to nitrogen in plant leaves.

The researchers wanted to know how this altered carbon-to-nitrogen ratio affected the insects that fed on the plants. They predicted the insects would eat more leaves to meet their nitrogen needs.

When they exposed the soybean field to elevated carbon dioxide levels, the researchers saw the expected effect: Soybeans in the test plot exhibited more signs of insect damage than those in nearby plots. A closer inspection showed that soybeans grown at elevated CO2 levels attracted many more adult Japanese beetles, Western corn rootworms and, during outbreaks of Asian soybean aphids, more of these than soybeans in other plots.

Caterpillars and other insect larvae need nitrogen to grow and build new tissues, but adult insects can survive and reproduce on a high carbohydrate diet. So it made sense that more adults would migrate to the high CO2 plants, DeLucia said.

But did the higher sugar levels in the leaves explain the whole effect? To find the answer, the team allowed beetles to live out their lives in one of three conditions: on a high CO2 plant, on a low CO2 plant outside the Soy FACE plot, or on a low CO2 plant grown outside the test plot but which had its sugar content artificially boosted.

“What we discovered was startling,” DeLucia said.

The beetles on the high CO2 soybean plants lived longer, and as a result produced more offspring, than those living outside the Soy FACE plot. Even those fed a supplemental diet of sugars did not see their life span extended.

“So here we were thinking that sugars were the main thing causing the beetles to feed more on these high CO2 leaves,” DeLucia said. “And that still may be true, but sugars aren’t what’s causing them to live longer and have more breeding events and offspring.”

The team turned its attention to the hormonal signaling pathways of the plants, focusing on a key defensive chemical the plants produced to ward off an insect attack. When insects eat their leaves, soybeans and other plants produce a hormone, jasmonic acid, that starts a chain of chemical reactions in the leaves that boost their defenses. Normally this cascade leads to the production of high levels of a compound called a protease inhibitor. When the insects ingest this enzyme, it inhibits their ability to digest the leaves.

“What we discovered is that leaves grown under high CO2 lose their ability to produce jasmonic acid, and that whole defense pathway is shut down,” Delucia said. “The leaves are no longer adequately defended.”

The higher carbohydrate content of the leaves and the lack of chemical defenses allowed the adult insects to feast and live longer and produce more offspring.

“This study demonstrates that global environmental change is multifaceted,” Berenbaum said. “The impact of elevated carbon dioxide on crippling the capacity of the plant to respond to insect damage is exacerbated by the presence of invasive insect pests in soybean fields. The Japanese beetle, as the name suggests, is a relatively recent arrival in Illinois soybean fields. It is causing considerable damage now but this study suggests that its ability to inflict damage will only increase over time.”

The researchers, both of whom also are affiliated with the university’s Institute for Genomic Biology, will now seek to determine whether the same process occurs in other plants.

Diana Yates | University of Illinois
Further information:
http://www.uiuc.edu

Further reports about: CO2 DeLucia Soy carbon dioxide plot produce soybean

More articles from Life Sciences:

nachricht A Map of the Cell’s Power Station
18.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht On the way to developing a new active ingredient against chronic infections
21.08.2017 | Deutsches Zentrum für Infektionsforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Nagoya physicists resolve long-standing mystery of structure-less transition

21.08.2017 | Materials Sciences

Chronic stress induces fatal organ dysfunctions via a new neural circuit

21.08.2017 | Health and Medicine

Scientists from the MSU studied new liquid-crystalline photochrom

21.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>