A rare form of parental care in plants has been captured by an exceptional amber deposit from 40 million years ago.
You can still see the seeds of an ancient pine cone in the deep yellow depths of the fossil. It's so unusual that seeds are germinating before their cone has delivered birth.
When the climate becomes warm and dry, pine cones open up and seeds are released into the soil, where they grow on their own.
Precocious germination is when seeds are sown in the parent plant and then grow into plants. This upbringing is usually only seen in flowering plants and occurs in less than 0.1 percent of the species.
It seems all but impossible among gymnosperms.
That's what makes this deposit so special. The images show stem bursting through the female parent cone.
Historical Biology, 2021.
The roots of the embryo are in the parental cone. The bar is 650 m.
A closer look at the roots. The bar is 400 m. Historical Biology, 2021.
In 1965, scientists observed this phenomenon. Researchers were able to identify the seeds within a single pine cone.
Some scientists think that frost or cold conditions may keep a pine cone from opening up and releasing its seeds, allowing them to stay warm and toasty inside.
George Poinar from Oregon State University says that seed germination in fruits is fairly common in plants that don't have seed dormancy.
It's rare in gymnosperms.
The Samland Peninsula of Russia is located in the southeastern Baltic Sea.
The deposit is thought to have been formed between 30 to 60 million years ago.
The pine cone is in great condition despite all that time. Researchers can still see clumps of pine needles at the tips of the embryonic sprout.
Historical Biology, 2021.
There are five needles from the pine cone. The bar is 100 m.
The authors think the ancient species is related to another extinct pine found in the same amber source, called Pinus cembrifolia.
This particular pine cone sticks out. It is the only fossil record of plants growing quickly.
Historical Biology, 2021.
This is what ancient pine cones look like. The bar is 630 m.
"That's part of what makes this discovery so intriguing, even beyond that it's the first fossil record of plant reproductive activity," says Poinar.
The seeds in the small pine cone could grow inside and the sprout could grow out so far before they died.
That is only a possibility. It's not clear if the embryo burst through the pine cone before it ended up in the amber.
There are still cases of movement even after an organisms gets trapped in amber.
The authors believe that the pine's thin cuticle could have kept the pine's resin from entering and killing the budding plant.
Poinar concludes that the first fossil record of seed viviparity in plants shows that it existed in gymnosperms.
"This condition probably occurred much earlier in plants that are vessels than in plants that are not vessels."
Maybe one day, we'll find some embryos among those plants.
The study was published in a journal.
