Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Deep within spinach leaves, vibrations enhance efficiency of photosynthesis


Biophysics researchers at the University of Michigan have used short pulses of light to peer into the mechanics of photosynthesis and illuminate the role that molecule vibrations play in the energy conversion process that powers life on our planet.

The findings could potentially help engineers make more efficient solar cells and energy storage systems. They also inject new evidence into an ongoing "quantum biology" debate over exactly how photosynthesis manages to be so efficient.

Through photosynthesis, plants and some bacteria turn sunlight, water and carbon dioxide into food for themselves and oxygen for animals to breathe. It's perhaps the most important biochemical process on Earth and scientists don't yet fully understand how it works.

The U-M findings identify specific molecular vibrations that help enable charge separation – the process of kicking electrons free from atoms in the initial steps of photosynthesis that ultimately converts solar energy into chemical energy for plants to grow and thrive.

"Both biological and artificial photosynthetic systems take absorbed light and convert it to charge separation. In the case of natural photosynthesis, that charge separation leads to biochemical energy. In artificial systems, we want to take that charge separation and use it to generate electricity or some other useable energy source such as biofuels," said Jennifer Ogilvie, an associate professor of physics and biophysics at the University of Michigan and lead author of a paper on the findings that will be published July 13 in Nature Chemistry.

It takes about one-third of a second to blink your eye. Charge separation happens in roughly one-hundredth of a billionth of that amount of time. Ogilvie and her research group developed an ultrafast laser pulse experiment that can match the speed of these reactions. By using carefully timed sequences of ultrashort laser pulses, Ogilvie and coworkers were able to initiate photosynthesis and then take snapshots of the process in real time.

The researchers worked with Charles Yocum, U-M professor emeritus in the Department of Molecular, Cellular and Developmental Biology and the Department of Chemistry, both in the College of Literature, Science, and the Arts to extract what's called the photosystem II reaction centers from the leaves. Located in the chloroplasts of plant cells, photosystem II is the group of proteins and pigments that does the photosynthetic heavy lifting. It's also the only known natural enzyme that uses solar energy to split water into hydrogen and oxygen.

To get a sample, the researchers bought a bag of spinach leaves from a grocery store. "We removed the stems and veins, put it in the blender and then performed several extraction steps to gently remove the protein complexes from the membrane while keeping them intact.

"This particular system is of great interest to people because the charge separation process happens extremely efficiently," she said. "In artificial materials, we have lots of great light absorbers and systems that can create charge separation, but it's hard to maintain that separation long enough to extract it to do useful work. In the photosystem II reaction center, that problem is nicely solved."

The researchers used their unique spectroscopic approach to excite the photosystem II complexes and examine the signals that were produced. In this way, they gained insights about the pathways that energy and charge take in the leaves.

"We can carefully track what's happening," Ogilvie said. "We can look at where the energy is transferring and when the charge separation has occurred."

The spectroscopic signals they recorded contained long-lasting echoes, of sorts, that revealed specific vibrational motions that occurred during charge separation.

"What we've found is that when the gaps in energy level are close to vibrational frequencies, you can have enhanced charge separation," Ogilvie said. "It's a bit like a bucket-brigade: how much water you transport down the line of people depends on each person getting the right timing and the right motion to maximize the throughput. Our experiments have told us about the important timing and motions that are used to separate charge in the photosystem II reaction center."

She envisions using this information to reverse engineer the process - to design materials that have appropriate vibrational and electronic structure to mimic this highly efficient charge separation process.


The paper is titled "Vibronic Coherence in Oxygenic Photosynthesis," scheduled for publication online on July 13 in Nature Chemistry. Other co-authors are from Vilnius University and the Center for Physical Sciences and Technology, both in Vilnius, Lithuania. The work is funded by the U.S. Department of Energy, the National Science Foundation and the U-M Center for Solar and Thermal Energy Conversion, as well as the Research Council of Lithuania.

Nicole Casal Moore | Eurek Alert!

Further reports about: Lithuania artificial extract leaves motions photosynthesis photosynthetic spinach steps vibrational

More articles from Life Sciences:

nachricht Locusts at the wheel: University of Graz investigates collision detector inspired by insect eyes
07.10.2015 | Karl-Franzens-Universität Graz

nachricht Flipping molecular attachments amps up activity of CO2 catalyst
06.10.2015 | DOE/Brookhaven 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: Kick-off for a new era of precision astronomy

The MICADO camera, a first light instrument for the European Extremely Large Telescope (E-ELT), has entered a new phase in the project: by agreeing to a Memorandum of Understanding, the partners in Germany, France, the Netherlands, Austria, and Italy, have all confirmed their participation. Following this milestone, the project's transition into its preliminary design phase was approved at a kick-off meeting held in Vienna. Two weeks earlier, on September 18, the consortium and the European Southern Observatory (ESO), which is building the telescope, have signed the corresponding collaboration agreement.

As the first dedicated camera for the E-ELT, MICADO will equip the giant telescope with a capability for diffraction-limited imaging at near-infrared...

Im Focus: Locusts at the wheel: University of Graz investigates collision detector inspired by insect eyes

Self-driving cars will be on our streets in the foreseeable future. In Graz, research is currently dedicated to an innovative driver assistance system that takes over control if there is a danger of collision. It was nature that inspired Dr Manfred Hartbauer from the Institute of Zoology at the University of Graz: in dangerous traffic situations, migratory locusts react around ten times faster than humans. Working together with an interdisciplinary team, Hartbauer is investigating an affordable collision detector that is equipped with artificial locust eyes and can recognise potential crashes in time, during both day and night.

Inspired by insects

Im Focus: Physicists shrink particle accelerator

Prototype demonstrates feasibility of building terahertz accelerators

An interdisciplinary team of researchers has built the first prototype of a miniature particle accelerator that uses terahertz radiation instead of radio...

Im Focus: Simple detection of magnetic skyrmions

New physical effect: researchers discover a change of electrical resistance in magnetic whirls

At present, tiny magnetic whirls – so called skyrmions – are discussed as promising candidates for bits in future robust and compact data storage devices. At...

Im Focus: High-speed march through a layer of graphene

In cooperation with the Center for Nano-Optics of Georgia State University in Atlanta (USA), scientists of the Laboratory for Attosecond Physics of the Max Planck Institute of Quantum Optics and the Ludwig-Maximilians-Universität have made simulations of the processes that happen when a layer of carbon atoms is irradiated with strong laser light.

Electrons hit by strong laser pulses change their location on ultrashort timescales, i.e. within a couple of attoseconds (1 as = 10 to the minus 18 sec). In...

All Focus news of the innovation-report >>>



Event News

EHFG 2015: Securing healthcare and sustainably strengthening healthcare systems

01.10.2015 | Event News

Conference in Brussels: Tracking and Tracing the Smallest Marine Life Forms

30.09.2015 | Event News

World Alzheimer`s Day – Professor Willnow: Clearer Insights into the Development of the Disease

17.09.2015 | Event News

Latest News

Kick-off for a new era of precision astronomy

07.10.2015 | Physics and Astronomy

Distinguishing coincidence from causality: connections in the climate system

07.10.2015 | Earth Sciences

Finding cannabinoids in hair does not prove cannabis consumption

07.10.2015 | Health and Medicine

More VideoLinks >>>