Login

GPC Members Login
If you have any problems or have forgotten your login please contact [email protected]


Through fossil leaves, a step towards Jurassic Park

For the first time, researchers have succeeded in establishing the relationships between 200-million-year-old plants based on chemical fingerprints. Using infrared spectroscopy and statistical analysis of organic molecules in fossil leaves, they are opening up new perspectives on the dinosaur era.

The unique results stem from a collaboration between researchers at Lund University, the Swedish Museum of Natural History in Stockholm, and Vilnius University.

"We have solved many questions regarding these extinct plants' relationships. These are questions that science has long been seeking answers to," says Vivi Vajda, a professor at the Department of Geology at Lund University and active at the Swedish Museum of Natural History.

The researchers have collected fossil leaves from rocks in Sweden, Australia, New Zealand and Greenland. Using molecular spectroscopy and chemical analysis, the fossil leaves were then compared with the chemical signatures from molecules in plant leaves picked at the Botanical Garden in Lund.

The use of genetic DNA analysis in modern research to determine relationships is not possible on fossil plants. The oldest DNA fragments ever found are scarcely one million-years-old. Therefore, the scientists searched for organic molecules to see what these could reveal about the plants' evolution and relationships.

The molecules were found in the waxy membrane, which covers the leaves and these showed to differ between various species. The membrane has been preserved in the fossil leaves, some of which are 200 million-years-old.

Using infrared spectroscopy, the researchers carried out analyses in several stages. Firstly, they examined leaves from living plants that have relatives preserved in the fossil archive. The analysis showed that the biomolecular signatures were similar among plant groups, much in the same way as shown by modern genetic DNA analysis.

When the method was shown to work on modern plants, the researchers went on to analyse their extinct fossil relatives. Among others, they examined fossil leaves from conifers and several species of Ginkgo. The only living species of Ginkgo alive today is Ginkgo biloba, but this genus was far more diverse during the Jurassic.

"The results from the fossil leaves far exceeded our expectations, not only were they full of organic molecules, they also grouped according to well-established botanical relationships, based on DNA analysis of living plants i.e. Ginkgoes in one group, conifers in another," says Vivi Vajda.

Finally, when the researchers had shown that the method gave consistent results, they analysed fossils of enigmatic extinct plants that have no living relatives to compare them with Among others, they examined Bennettites and Nilssonia, plants that were common in the area that is now Sweden during the Triassic and Jurassic around 250-150 million years ago. The analysis showed that Bennettites and Nilssonia are closely related. On the other hand, they are not closely related to cycads, which many researchers had thought until now.

Per Uvdal, Professor of Chemical Physics at Lund University and one of the researchers who conducted the study, considers that the overall results are astounding.

"The great thing about the biomolecules in the leaves' waxy membranes is that they are so much more stable than DNA. As they reflect, in an indirect way, a plants DNA they can preserve information about the DNA. Therefore, the biomolecules can tell us how one plant is related in evolutionary terms to other plants," he says.

The researchers are now going to extend their studies to more plant groups.

Read the paper: Molecular signatures of fossil leaves provide unexpected new evidence for extinct plant relationships.

Article source: Lund University.

Image credit: Stephen McLoughlin

News

Harvard forest report: Forests, funding, and conservation in decline across New England

New England has been losing forestland to development at a rate of 65 acres per day, according to a new report released by the Harvard Forest, a research institute of Harvard University, and a team of authors from across the region. Public funding for land protection has also been steadily declining in all six New England states and is now half what it was at its 2008 peak; with land conservation trends following suit.


Plant physiology: Adjusting to fluctuating temperatures

Later leaf emergence, earlier leaf loss: A new study of Ludwig-Maximilians-Universitaet (LMU) in Munich shows that the average vegetation periods of trees and shrubs in North America are intrinsically three weeks shorter than those of comparable species in Europe and Asia.


More mouths can be fed by boosting number of plant pores

Scientists at Institute of Transformative Bio-Molecules (ITbM), Nagoya University have synthesized a new bioactive small molecule that has the ability to increase stomata numbers on flowering plants without stunting their growth. The team’s new discovery could help elucidate the stomatal development mechanism in plants.