Seed germination—a crucial stage in the growth of all plants—usually occurs in the soil after the seed has fallen from the parent plant. In some rare cases, early germination – A kind of life or feast – occurs when the seed sprouts while it is still inside the fruit. in a new paper Published in the magazine Historical BiologyProfessor George Poinar Jr of Oregon State University described the first case of the early germination of a fossil plant involving a number of seeds that sprouted into a pine cone embedded in a piece of ancient Baltic amber. 40 million years ago (Eocene epoch).

Prof Poinar said: “Seed germination is critical to the growth of all plants and usually occurs in the soil after seeds have fallen off.”

“We tend to associate life — embryonic development within the father — with animals and forget that this sometimes happens in plants. By far, most of these cases involve angiosperms.”

“Angiosperms, which directly or indirectly provide most of the food that people eat, have flowers and produce seeds that are surrounded by the fruit.”

Germination from seed to fruit is very common in plants that lack seed dormancy, such as tomatoes, peppers and grapefruit, and occurs for several reasons. But it is rare in gymnosperms. “

The early sprouting of pine cones is so rare that only one natural example of this disease, dating back to 1965, has been described in the scientific literature.

“This is part of what makes this discovery so intriguing, even as it is the first fossil record of plant vitality to include seed germination,” said Professor Poinar.

“I find it fascinating that the seeds of this little pine are starting to sprout inside the cone and that the buds can grow so far before they perish in the resin.”

At the end of the shoots are clusters of needles, some in bundles of five, linking the fossil to an extinct pine species. grated pine, which was previously described from Baltic amber.

The needles are at the hypocotyl end of Pinus cembrifolia.  Image credit: George Poinar Jr., Oregon State University.

pointed needles grated pineHypocotyl. Image credit: George Poinar Jr., Oregon State University.

According to the scientist, life in plants generally appears in two ways.

“Early germination is the more common of the two, and the other is plant life, such as when an onion comes out directly from the head of the mother plant,” he said.

“If the seeds remained for this fossil, the seeds produced fully visible embryonic stems in the amber.”

It is not known if these stems, called hypocotyls, appeared before the cone turned amber. However, from their position, it appears that some, if not most of the growth occurred after the pine cone fell into the resin.

Research on the viability of existing gymnosperms suggests that the condition may be related to winter frost.

Professor Poinar said: “A slight frost would have occurred if the Baltic Amber Forest had been as humid, warm and temperate as it was supposed to.”

“This is the first fossil record of seed viability in plants, but it is likely that this case occurred a little earlier than the Eocene record.”

“There is no reason why plant life hundreds of millions of years ago did not appear in ancient spore plants such as ferns and lycopods.”

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Georg Poinar, Jr. Early germination of pine cones in Eocene Baltic amber. Historical Biology, published November 8, 2021; doi: 10.1080/08912963.2021.2001808

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