Researchers have discovered a newly fossilized specimen of a plant seed called . AlasemeniaIt is one of the oldest known examples of winged seeds. This discovery helped advance our understanding of the origin and early evolution of wind dispersal strategies in plants.

A study published in the journal e-Lifedescribes this seed from the Late Devonian period (about 360-385 million years ago). With the help of mathematical analysis, it was shown that the seed has a three-winged structure. Alasemenia It is better adapted to wind dispersal than seeds with one, two or four wings.

Wind-assisted seed dispersal is a natural mechanism that allows plants to disperse their seeds to new regions, reducing competition for resources. Examples of such strategies include winged seeds, as in maples, or parachutes, as seen in dandelions and milkweeds.

The study showed that: Alasemenia It has three wings that cover the seed and contribute to its effective dispersal by wind. This discovery is an important step in understanding how plants have evolved seed dispersal mechanisms since the Devonian period.

Evolutionary significance of the Late Devonian

The oldest known plant seeds date back to the Late Devonian period. “This period marks an important evolutionary turning point in the history of plants, as they transitioned from spore-based reproduction to seed-based reproduction, as in ferns and mosses,” explains lead author Deming Wang, a professor at the Key Laboratory of Orogenic Studies. Generations and Crustal Evolution, Department of Geology, Peking University, Beijing, China. “However, little is currently known about wind dispersal in seeds, as most fossils have no wings and are usually surrounded by a protective dome.”

Cucules are cup-like structures that partially enclose seeds, similar to acorns or chestnuts (although Devonian capules are not of the same origin as these modern ones) and may be associated with other methods of dispersal, such as water transport.

To better understand the early mechanism of wind dispersal, Wang and colleagues studied several Late Devonian seed fossils from the Jianchuan Mine in Xinhan City, Anhui Province, China. From this, they identified a new fossil seed. Alasemenia.

They announced their features for the first time AlasemeniaBy carefully analyzing fossil samples, including making cross-sections to see the internal structure of the seed. They found the seeds Alasemenia It is approximately 25-33 mm long and, unlike most other seeds of the period, has no distinct calyx. In fact, this is one of the earliest known records of a seed without a cupula; It is 40 million years older than previously thought.

Structural analysis of Alasemenia

Each seed is covered with a layer of shell, or seed coat, that splits outward to form three wing-like lobes. These wings taper at the tips and fold outward, creating broad, flattened structures that help the seed catch the wind.

Then the team compared Alasemenia With other known Late Devonian winged seeds: varsthenia And guazia. Both of these seeds have four wings: guazia a wide and flat varsthenia short and straight. They performed a quantitative mathematical analysis to determine which seeds had the most efficient wind dispersal. This indicated the existence of an odd number of wings. AlasemeniaIt provides a more consistent, high-speed rotation as the seeds descend from the branches, allowing them to capture the wind more efficiently and therefore disperse farther from the parent plant.

“Our discovery Alasemenia “It increases our knowledge of the origin of wind dispersal strategies in early land plants,” says senior author Pu Huang, an associate research fellow at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences. “Combined with our previous knowledge guazia And warsteinya “We conclude that winged seeds from canopy growth emerged as an early form of wind dispersal strategy during the Late Devonian, before other methods such as parachutes or feathers.”

“Thanks to the visible three-winged seeds Alasemenia “Dicotyledon seeds came in the late Devonian period, followed by dicotyledon seeds in the Carboniferous period, and then monocot seeds came in the Permian period,” adds Wang.