Amber Fossil Shows Ancient Reproduction in Flowering Plant
Researchers have stumbled across a 100-million-year old piece of amber, perfectly preserving flowering plant life from the Cretaceous Period. Encased within amber surroundings, a cluster of 18 small flowers is readily discernible, including one that was in the process of manufacturing entirely new seeds.
Researchers from Germany, and Oregon State University, published their findings on the fossilized plant in the Journal of the Botanical Institute of Texas. The piece of amber was originally part of a larger segment that contained a fossil scorpion. Some 100 million years ago, flowing tree sap covered the specimen and the plant was slowly preserved during the fossilization process, ultimately, transforming it into a semi-precious gem. The specimen – acquired from the Noije Bum 2001 Summit Site in the Hukawng Valley of Myanmar – will, eventually, make its way to the Senckenberg Museum and Research Institute in Frankfurt.
The researchers performed microscopic analysis to identify the species of plant present – confirmed as Micropetasos burmensis. The flower cluster was discovered in remarkable condition and, in a recent press release, was described as one of the most complete specimens ever to have been encountered in amber.
In addition, the researchers acquired microscopic images of a series of tiny pollen tubes, flourishing from grains of pollen. Two of these germinated pollen tubes extended from the grains into the plant’s stigma – a receptive female reproductive organ.
George Poinar, Junior, a professor emeritus who works in the Department of Integrative Biology at the Oregon State University College of Science, recently spoke about the unprecedented condition of the specimen, along with the discovery of the intact pollen tubes:
“In Cretaceous flowers we’ve never before seen a fossil that shows the pollen tube actually entering the stigma… This is the beauty of amber fossils. They are preserved so rapidly after entering the resin that structures such as pollen grains and tubes can be detected with a microscope.”
According to Poinar, the pollen of the fossilized flowers demonstrated a “sticky” aesthetic, potentially indicating that they had been transported by roaming insects. Indeed, the authors of the paper highlight the curved nature of the style, and the stout floral pedicels, suggesting their arrangement may have played a part in aiding insect pollination.
This offers additional insight into the variety of biological life that existed within the ecosystem, during this distant period. The researchers suggest Melittosphex burmensis – a bee that has a length of less than 3 millimeters that previously occupied the Burmese amber forest – to have been a possible candidate involved in the pollination process.
During the Cretaceous period, ferns dominated open and dry lands and dinosaurs roamed among ferns and cycads – seed plants, typically characterized by sturdy trunks and a crown of large leaves. However, during the Cretaceous Period, flowering plants and novel lineages of mammals and birds began to emerge. According to Poinar, it was the evolution of flowering plants that spurred radical change in the “… biodiversity of life on Earth, especially in the tropics and subtropics.”
It was the interplay between these flowering plants and the myriad of scurrying insects and small mammals that facilitated the distribution and evolution of these plants. Poinar expresses his surprise in finding that the reproductive methods, observed in the modern plants of today, already existed some 100 million years ago.
By James Fenner