Tag Archives: seed

Fossil Friday: Early-sprouting pine cone preserved in amber

A new fossil described by researchers at the Oregon State University captured a very rare occurrence in the distant past: an example of precocious germination when seeds sprout inside a living plant.

Image credits George Poinar Jr., Oregon State University.

The seed belonged to an ancient pine tree and sprouted while still inside its cone. The plant lived around 40 million years ago and was discovered preserved in a piece of Baltic amber. Several plant embryos are seen sprouting from the cone inside the amber.

A bit too early

“Crucial to the development of all plants, seed germination typically occurs in the ground after a seed has fallen,” said George Poinar Jr. of the Oregon State College of Science, an American entomologist and sole author of the paper. “We tend to associate viviparity – embryonic development while still inside the parent – with animals and forget that it does sometimes occur in plants.”

The findings are particularly interesting because the fossil belongs to a conifer — which belongs to the greater botanical family of gymnosperms. While precocious germination is rare, it is more commonly found in angiosperms, flowering plants which produce their seeds inside fruits. Gymnosperms, on the other hand, produce “naked” seeds; seeds that are not enclosed in mature fruits or ovaries. It’s pretty common to see gymnosperm producing cones, for example.

“Seed germination in fruits is fairly common in plants that lack seed dormancy, like tomatoes, peppers and grapefruit, and it happens for a variety of reasons,” Poinar adds. “But it’s rare in gymnosperms.”

In fact, examples of precocious germination in pine cones is so rare that only one such event (from 1965) has been described in scientific literature, he adds. Their rarity is part of what makes the current discovery so exciting. Added to that, this is the first time this phenomenon has been seen in a fossilized specimen.

Based on the structure of the sprout — the bundles of five needle clusters surrounding its tips in particular — Poinar attributed this specimen to the extinct pine species Pinus cembrifolia. This species has been previously described from other specimens of Baltic amber; examples of pines in Baltic amber are rare to begin with, he adds, despite the fact that the morphology of their cones makes them ideal for preservation in amber and keeps them virtually intact through this process.

Precocious germination is the more common of two types of viviparity, Poinar explains, the other being known as ‘vegetative viviparity’. In the case of this fossil, it’s very likely that some if not all the development of the sprout occurred before the cone fell from its mother tree into resin.

“Often some activity occurs after creatures are entombed in resin, such as entrapped insects depositing eggs,” Poinar said. “Also, insect parasites sometimes flee their hosts into the resin after the latter become trapped. In the case of the pine cone, the cuticle covering the exposed portions of the shoots could have protected them from rapid entrance of the resin’s natural fixatives.”

Beyond how spectacular this specimen itself is, the finding helps us gain a better idea of the environmental conditions in the Baltic region during the time of this pinecone. Previous research on viviparity occurrence in gymnosperms suggests that such events are linked to winter frosts. Light frosts would have been possible in the region if it had a humid, warm-temperate climate; this conclusion supports previous hypotheses regarding Baltic climates in the Eocene, the period when this pine cone grew and fell into amber.

The paper “Precocious germination of a pine cone in Eocene Baltic amber” has been published in the journal Historical Biology.

Blue crystal.

Meteorites carrying both water and organic compounds point to an ocean world “seeding life” in the universe

New research raises an intriguing possibility — that of an alien ocean world seeding life throughout space.

Blue crystal.

One of the meteorites’ tiny crystals bearing organic compounds.
Image credits Queenie Chan / The Open University.

In 1998, a group of friends had to cut their basketball game short for a somewhat unexpected reason — a meteorite decided to crash just yards away from the hoop.

Seeds of life

But that seems to have been fortune’s plan all along, as the rock seems to be a harbinger of life rather than death. Initial analysis of the chunk of meteorite, along with another that fell in Morocco the same year, revealed traces of liquid water and other organic components that underpin life. Now, an in-depth chemical analysis points to an ancient ocean world as the likely cradle of these organic compounds. It’s possible that such material could seed life on planets they land on, including the early Earth.

Initial analysis revealed that the main elements inside the meteorites include liquid water and amino acids. Taken together, that’s not really news — we’ve found such compounds in meteorites and in space before. They might not be as rare as we tend to believe. However, we’d never seen them together in a single alien sample before these two bits of space rock were first analyzed.

That made the meteorites really special, so they were preserved at NASA’s Johnson Space Center. Keen to find out more, an international team of researchers has recently sampled the organic compounds locked away in these meteorites’ 2-mm long salt crystals using an X-ray beamline and microscope, as well as other chemical experiments.

Along with traces of liquid water, they report finding organogenic elements like carbon, oxygen, and nitrogen, along with more complex organic compounds such as hydrocarbons and amino acids. In other words, we’ve found the fundamental building blocks of life as we know it right next to water — in a space rock.

“This is really the first time we have found abundant organic matter also associated with liquid water that is really crucial to the origin of life and the origin of complex organic compounds in space,” says study lead author Queenie Chan.

“We’re looking at the organic ingredients that can lead to the origin of life.”

After discovering this exciting chemical cocktail, the next step was to see where the meteorites came from, and where they inherited their organic matter. Their complex chemistry (in comparison to other meteorites) makes it unlikely that they’re simply left-over bits from the creation of the Solar System. Instead, the team narrowed their search to an ancient ocean world — similar to today’s Enceladus or Ceres. Water and ice plumes (which are relatively commonly-seen on such bodies) shooting out into space could have doused the meteorites, locking the planet’s organic compounds in the salt crystals.

According to co-author Yoko Kebukawa, the organic matter seen in these samples is “somewhat similar” to what we’ve previously found in primitive meteorites. The results of the analysis support the idea that the “organic matter originated from a water-rich, or previously water-rich parent body”, she explains, adding that it’s “possibly Ceres“.

Encased in the salt crystals, such biomolecules could safely make it across the cosmos. Even microscopic life could survive on a space-cruise within a similar system, the team says. Once in space, all kinds of things could happen to help spread these seeds of life around — collisions between asteroids, for example, would push them along or shatter them into even more ‘seeds’. After making it to a planet, such rocks could jump-start life on the surface.

“Everything leads to the conclusion that the origin of life is really possible elsewhere,” Chan adds. “There is a great range of organic compounds within these meteorites, including a very primitive type of organics that likely represent the early solar system’s organic composition.”

Next, the team plans to look at other crystals embedded in the meteorites that haven’t yet been analyzed. Who knows what we may find? Maybe a tiny alien bacterium swimming around?

The paper “Organic matter in extraterrestrial water-bearing salt crystals” has been published in the journal Science.

In a secret location in Michigan lies one of the longest running experiments

Over one century ago, in 1879, a botanist called William Beal buried 20 glass bottles in a secret place in the campus of  the Michigan State University. Each one was filled with sand and more than 1,000 seeds, and was angled with their uncorked mouths slanted downwards, so that they don’t collect water. The idea is to see, decade after decade, whether or not the seeds are still viable.

Kurt Stepnitz/Michigan State University

Four years from now, botanist Frank Teleweski will covertly do what many other generations of scientists have done before him: dig out a bottle and see if the seeds still work. After 137 years, just five of them remain, and some seeds are still going strong.

While the experiment seems deceivingly simple, it’s actually been highly effective. The original goal was to help deal with the bane of farmers: weeds. Keep in mind, this was way before the age of pesticides, and farmers often found that no matter how much they remove the weeds, identical ones pop up in their place. This was confirmed by this experiment, as the only plant to still germinate from all the bottles is a weed — Verbascum blattaria, a weed commonly called moth mullein.

“In 1980, there were three species which germinated,” Telewski said. However, the fact that moth mullein is the only one to survive the test of 120 years is not unexpected. “It is the only plant to consistently germinate in all of the tests. It will be very interesting to see if the seeds will still germinate 20 years from now.”

It’s well known that seeds can last for a long time without water and nutrients, awaiting the right moment to pop up. However, we don’t know just for how long they can resist. The original experiment was never meant to last this long. Bottles were supposed to be taken out every five years so that the whole thing can last for a century. However, biologists decided to extend it when they saw the results. The last bottle will be taken out in 2100, 221 years after the bottles were buried.

“This information explains why there are so many weeds which can germinate in a freshly plowed field,” Telewski said. “Plowing also mixes fresh seed into the deep seed bank. This information is also of interest to plant ecologists who study regeneration of disturbed land from existing seed banks in soils. If a site is disturbed by fire, flood, wind or any thing else, vegetation can recover from the existing seeds in the soil, which can remain viable for years. The area doesn’t need to have seeds blown in or carried in from other vegetated areas.”

Both seed size and number can be increased at the same time, an important find for food security

For a long time, scientists have believed there’s a sort of net trade-off between the number of seeds and the size of the seed a plant yields. Namely, if a plant yields more seeds, these will be smaller or, oppositely, if a the size of the seed is greater, there will be fewer seeds. Now, scientists at University of Bath’s Department of Biology & Biochemistry found this isn’t a mutually inclusive link. Their research shows that it’s possible to increase seed number and seed size both at the same time, a finding with great implications for food security.

More, bigger seeds possible

hemp-seeds-hands

Photo: gmeducation.org

The team studied naturally occurring genetic variation in Arabidopsis thaliana, a close relative of oilseed rape. Using a new tool called  Multiparent Advanced Generation Inter-Cross (MAGIC) lines, the precise locations on chromosomes of genes that affect size and number of seeds were identified. With these locations at their disposal, the researchers then focused on determining whether or not these genes were connected with another. According to the paper published in Genetics, genetic factors that control seed number and size are located on different parts of the genome, hence seed size and number can be controlled independently without affecting one or the other.

“This study shows it’s actually possible to increase both seed size and seed number. These results are very promising, especially for food security,” says Dr Paula Kover, Senior Lecturer in Genetics at the University of Bath.

“The next step is to narrow and to identify the exact genes involved in seed size and seed number so that we can use breeding techniques to maximise yields.”

Some 850 million people worldwide as classes as living in hunger, a number that is expected to surge as the world’s population will rise by 3 billion by 2050. The arable landmass is expected to stay the same, though, so a solution would be to grow more per square meter. The U.S. average corn yields have increased from approximately 1.6 tonnes/ha in the first third of the 20th century to today’s approximately 9.5 tonnes/ha. This dramatic yield improvement is due to the development and widespread use of new farming technologies such as hybrid corn, synthetic fertilizers, and farm machinery.

[RELATED] Climate change will cause lower crop yields

Seed crops haven’t been that well investigated, though. As biodiesel production increases, food crops are ever stressed by the competition for the farmland. Increasing seed yield  through genetic manipulation thus has the potential to significantly improve how both our food and energy needs are met.

It’s important to note that growing more is just part of the solution. Cutting waste is arguably more important. Coincidentally, we also posted today a story about how 20 to 40 percent of the fresh food grown by farmers in developed countries is thrown away because it doesn’t look pretty. That’s beside the  20 to 40 percent of the world’s potential crop production that’s already lost annually because of the effects of weeds, pests and diseases. Overall, the amount of food lost or wasted every year is equivalent to more than half of the world’s annual cereals crop (2.3 billion tonnes in 2009/2010). Of course, food is perishable and doesn’t last forever, but with a bit of due diligence, each of us can do his or her part by cutting on waste.