Posted: Nov 20, 2021 13:34 GMT
The botanical condition recorded in pineapples, which occurs when the seeds begin to sprout before ‘giving birth’, is so rare that only one natural example has been described in the scientific literature in 1965.
A scientific study uncovers the first fossil evidence of a rare botanical condition known as early germination, in which seeds sprout before ‘giving birth’, the University of Oregon reported Tuesday.
The work describes the first case of early germination of a fossil plant, an approximately 40 million-year-old pineapple encased in Baltic amber from which several embryonic stems are emerging.
“The germination of seeds, fundamental for the development of plants, generally occurs in the soil after a seed has fallen,” said the author of the research, George Poinar Jr. “We tend to associate viviparity [el desarrollo embrionario mientras todavía está dentro del progenitor] with animals and we forget that sometimes it happens in plants, “he added.
This viviparity or early germination is rarely seen in flowering plants, and even then, occurs in less than 0.1 percent of species, according to a study by the Botanical Society of Germany and the Netherlands.
“Early germination” in pineapples
As for gymnosperm plants, such as conifers, this form of growth is almost non-existent, since they produce “naked” or unenclosed seeds. Early germination in pineapples is so rare that only one natural example of this condition, from 1965, has been described in the scientific literature, Poinar said.
“That’s part of what makes this discovery so intriguing, even beyond the fact that it is the first fossil record of plant viviparity to involve seed germination,” he said. “I find it fascinating that the seeds of this little pineapple can begin to germinate inside the cone and that the shoots can grow so long before they perish in the resin, “he said.
On the other hand, it is not common to find a pine cone in Baltic amber. Those that appear are appreciated by collectors and, because the scales of the cones are hard, they are usually very well preserved and seem real, according to the scientist.
The scientist noted that it is unclear whether the embryonic stems appeared before the cone was encased in amber. However, based on your position, it appears that some, if not most, growth occurred after the pineapple fell into the resin.
Also, at the tips of the shoots are clusters of needles, which associate the fossil with the extinct species of pine ‘Pinus cembrifolia’, stated the author.
Regarding the investigation of viviparity in existing gymnosperms, it is suggested that the condition could be related to winter frosts. Light frosts would have been possible if the Baltic amber forest had a humid and warm temperate environment, as has been postulated, Poinar explained.
To conclude, the scientist assured that, despite the fact that his study represents the first fossil record of seed viviparity in plants, “this condition probably occurred well before this fossil from the Eocene geological age”, which began some years ago. 56 million years ago and ended about 34 million years ago. “There is no reason why vegetative viviparity could not have occurred hundreds of millions of years ago in ancient spore-bearing plants such as ferns and lycopods,” he said.
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