110 million year old dormant flower seeds discovered

Scientists have discovered clues about an ancient flower that existed at the same time as the Ankylosaurus and Iguanadon dinosaurs.

The first flower seeds to exist from the Cretaceous period were analyzed using a CT scanner. Photo: Live Science

According to Live Science, Swedish scientists have discovered tiny flower seeds from the Cretaceous period dating back 110-125 million years, the oldest known seeds of flowering plants. These small seeds help biologists learn about the origin of today's flower varieties.

The seeds are tiny. The largest are no more than 2.5mm in diameter and are so well preserved that it is possible to see their cellular structures. For the first time, scientists have been able to see the embryo, the part of a seed where a new plant grows and emerges, and the nutrient-storing tissues that surround it. This rare find helps us understand how Cretaceous seeds developed, and how they differed from modern plants.

Else Marie Friis, head of a research team at the Swedish Museum of Natural History, has been analyzing several fossil specimens of flowering angiosperms found underground in Portugal and North America.

She and her colleagues used a new imaging technique: X-ray micro-CT, which allows them to explore tiny fossils without damaging the specimen. They scanned about 250 seeds from 75 species from many genera, revealing the embryo and nutritional structures inside the seed in great detail.

About half of the fossil seeds analyzed contained complete cell structures within the seed coat, and about 50 contained partial or complete embryos. Once they had two-dimensional images of the embryos, they used software to create 3D simulations and compare the differences in shape and size between the seeds. In some cases, the similarities between the embryos could prove that modern plant varieties are related to Cretaceous angiosperms.

“These observations give us a new insight into the early life cycle of the first angiosperms, which is really important for understanding the ecology of flowering plants in the early Cretaceous,” said Friis.

During the Cretaceous, angiosperms flourished and diversified. Many new species of insects also appeared during this period, which may have helped flowering plants flourish in the ancient world.

Previous evidence from both present-day plants and fossils suggests that the first angiosperms grew on land. All the seeds analyzed in this study were preserved in a state of dormancy. These embryos are tiny, less than 0.25mm, so they need to develop further inside the seed before they can germinate.

"Our discovery supports the hypothesis that embryos can hibernate inside seeds, meaning they can wait out harsh environmental periods and delay development until they encounter more favorable living conditions, a survival strategy that has been passed down to flowering plants today," said Ms Friis.

The above study was published in the journal Natue on December 16, 2015.

According to VNE