July 5, 2007, 9:00 PM CT

Molecular Mechanics of Phototropism

In a paper reported in the Journal of Biological Chemistry, researchers at the University of Missouri-Columbia reported molecular-level discoveries about the mechanisms of phototropism, the directional growth of plants toward or away from light.

Phototropism is initiated when photoreceptors in a plant sense directional blue light. Understanding phototropism is important because it could lead to crop improvement, said Mannie Liscum, professor in the Division of Biological Sciences in MU's College of Arts and Science and Christopher S. Bond Life Sciences Center.

"By understanding how phototropism works at a molecular level, we can work toward engineering plants that produce more biomass or have increased drought tolerance, among other things. For example, we could use this information to optimize plants' ability to capture light for photosynthesis, which would result in more energy capture and thus growth, or potentially agronomically useful biomass," Liscum said.

Liscum and doctoral student Ullas Pedmale studied the regulation of phototropic signaling in Arabidopsis thaliana, a weedy flowering plant usually used as a model in laboratory studies. Focusing on non-phototropic hypocotyls 3 (NPH3), a protein known to be essential for phototropic responses, they examined its phosphorylation, the addition or removal of a phosphate group to the protein molecule. Using a series of pharmacological therapys and immunoblot assays, the team discovered that NPH3 was a phosphorylated protein - a protein with a phosphate group attached - in seedlings grown in the darkness. When the seedlings were exposed to light, they became dephosphorylated, or lost their phosphate group......... Posted by: Erica      Read more         Source

June 27, 2007, 5:48 PM CT

Study Explains Rainforest Similarities

Celebrated in Buddhist temples and cultivated for its wood and cottony fibers, the kapok tree now is upsetting an idea that biologists have clung to for decades: the notion that African and South American rainforests are similar because the continents were connected 96 million years ago.

Research by University of Michigan evolutionary ecologist Christopher Dick and his colleagues shows that kapok---and perhaps other rainforest--trees colonized Africa after the continents split when the trees' seeds traveled across the ocean.

The findings, funded by the National Science Foundation (NSF), appear online this week in the journal Molecular Ecology.

"This research provides vital information for one of the most highly threatened areas of the planet, tropical rainforests," said Sam Scheiner, program director in NSF's Division of Environmental Biology, which funded the research. "In order to plan for and mitigate global climate change, we need to understand the history of life on Earth through studies like this one".

Oceanic dispersal links the world's rainforests, said Dick, "and this study is one of the first to catch that process in action at the species level. Eventhough single seeds are very unlikely to survive an oceanic voyage and then successfully become established elsewhere, such improbable events become probable over 10 to 15 million years"......... Posted by: Erica      Read more         Source

June 20, 2007, 11:06 AM CT

Plant Life On Extrasolar Earthlike Planets

When we think of extrasolar Earth-like planets, the first tendency is to imagine weird creatures like Jar Jar Binks, Chewbacca, and, if those are not bizarre enough, maybe even the pointy-eared Vulcan, Spock, of Star Trek fame.

But researchers seeking clues to life on extrasolar planets are studying various biosignatures found in the light spectrum leaking out to Earth to speculate on something more basic and essential than the musical expertise of Droopy McCool. They are speculating on what kind of photosynthesis might occur on such planets and what the extrasolar plants might look like.

Paint it black

It could be the plants are black, says Robert Blankenship, Ph.D., Lucille P. Markey Distinguished Professor in Arts & Sciences at Washington University in St. Louis. But it all depends on what size and light intensity of star - or sun - the planet feeds off, and the extrasolar planet's atmospheric chemistry.

Plants on Earth are green because of chlorophyll, which harnesses the energy of the sun to make sugars for metabolism. But our plants aren't completely efficient - they waste a little bit of light.

"Ideally, what you want is a black molecule that absorbs all of the light," Blankenship said. "There could be another system developed on an extrasolar planet where plants are completely black if the spectrum of light that's available to organisms is different from the light available to organisms on Earth......... Posted by: Erica      Read more         Source

June 18, 2007, 10:02 PM CT

How to control tree height

Forest researchers at Oregon State University have used genetic modification to successfully manipulate the growth in height of trees, showing that its possible to create miniature trees that look similar to normal trees but after several years of growth may range anywhere from 50 feet tall to a few inches.

This is a proof of concept that tree height can be readily controlled by genetic engineering techniques. It opens the door to a wide variety of new products for the ornamental and nursery industries, experts say, if regulatory hurdles can be overcome a big if.

The findings were recently reported in the journal Landscape Plant News.

From a science perspective, this is a very interesting accomplishment and theres no doubt it could be made to work, said Steven Strauss, a professor of forest science at OSU.

But further development may be precluded by social, legal and regulatory obstacles, he said. Clearly there would be concerns whether the market for specialty tree products such as this would be strong enough to make it worth the large investments of time, money and testing that current regulation of genetically modified organisms would require, at least in the U.S.

That aside, he said, it appears that with further research and development programs, it would indeed be possible to create an elm tree which ordinarily would grow to 100 feet or more that is only five feet tall at maturity, a charming addition that would fit nicely on a backyard deck. Or a 30-foot version that might be a better fit on urban streets. Or, in fact, just about any height in between. Other changes can also affect foliage shapes or color in very attractive ways, and some might have value in cleaning up environmental pollution......... Posted by: Erica      Read more         Source

Wed, 13 Jun 2007 20:21:25 GMT

Alnus sieboldiana

A grateful thanks to Mbc of Germany for contributing today's image via the UBC BG BPotD Submissions forum in this thread. Mbc made this photograph while on a mountainside hike near Kyoto, Japan.

When you become familiar with the scientific names of plants, you can sometimes glean some additional information about a plant new to you at a glance. In this case, the epithet sieboldiana tells me that the plant is named after Philipp Franz von Siebold, which in turns suggests the plant is native to Japan (and indeed it is). A similar trick works for recognizing the name of the person (or people) who scientifically described a species and published a name (i.e., the author). For example, Acer carpinifolium was published by Sieb. & Zucc. — and again, one can be reasonably certain it is native to at least Japan. The reason this works, of course, is because botanists (prior to air travel) tended to work in a specific geographical area or on a particular regional flora.

Von Siebold was a German-born physician and botanist. While working as a Dutch army medical officer, von Siebold was stationed in Japan as a scientist and doctor during the 1820s. It was during this time that he amassed botanically and horticulturally valuable collections of thousands of both living and preserved specimens of plants. The preserved specimens later resulted in von Siebold and Zuccarini (Sieb. & Zucc.) coauthoring Flora Japonica. Von Siebold's first tenure in Japan ended when he was discovered to possess detailed maps of Japan and Korea, an act for which he was expelled in 1830 (another act which likely would have sent him home sooner, had it been discovered, was aiding the smuggling of young tea plants to the Dutch colony in Java).

While the fruiting structure illustrated in today's photograph resembles a conifer cone, I notice the term is avoided in the summary of Alnus in the Flora of North America. Instead, the structure is described as an infructescence, consisting of persistent, 5-lobed, woody scales. It is the result of the bracts of the fruiting catkin becoming woody as the seeds mature. Posted by: Daniel Mosquin      Read more     Source

June 10, 2007, 9:01 PM CT

Columbine Flowers Develop Long Nectar Spurs

In flowers called columbines, evolution of the length of nectar spurs--the long tubes leading to plants' nectar--happens in a way that allows flowers to match the tongue lengths of the pollinators that drink their nectar, biologists have found.

The scientists were Justen Whittall of the University of California at Davis and Scott Hodges of the University of California at Santa Barbara. They were funded by the National Science Foundation (NSF). Their results appear in this week's issue of the journal Nature.

Darwin once proposed a co-evolutionary "race" to explain how natural selection might account for the evolution of very long nectar spurs in flowers, said Hodges. "In Darwin's race, plants with the longest spurs and pollinators with the longest tongues [to tap the flowers' nectar] would be favored by natural selection, and--in a never-ending process--continually drive the plants' spurs and the pollinator tongues to exceptionally long lengths".

But it turns out, Whittall and Hodges found, that evolution acts in a more one-sided fashion in a number of plants: the plants evolve nectar spurs to match the tongue-lengths of the pollinators. Then the process stops, and only starts again when there is a change in pollinators.

Whittall and Hodges proved this idea by testing the columbine genus Aquilegia, which is pollinated by bumblebees, hummingbirds and hawkmoths......... Posted by: Erica      Read more         Source

June 10, 2007, 7:34 PM CT

Oxygen trick could see organic costs tumble

A simple, cheap therapy using just oxygen could allow growers to store organic produce for longer and go a long way towards reducing the price of organic fruit and vegetables, reports Lisa Richards in Chemistry & Industry, the magazine of the SCI.

Currently UK shoppers have to pay twice as much for some organic products. Organic apples, for example, are around double the price of conventionally grown apples in Sainburys, Waitrose and Tesco.

One of the major contributing factors affecting the price is the short shelf life of organic produce. Conventional produce can be treated with inexpensive chemicals to aid preservation. But these cannot be used for organic produce, as by definition no artificial chemicals are used during processing.

With some organic fruit and veg, there can be large losses [during storage], Claudia Ruane, spokes person for Abel & Cole organic produce retailers told C&I. Ruane explained that eventhough a number of organic farms do have reasonably sophisticated refrigeration units, there are very expensive and used only for brief storage before collection. These are important and costly but if paying out for these facilities can ensure a whole crop is not rejected by a retailer because it is a little limp or dehydrated, then it is a cost that has to be absorbed, she said......... Posted by: Erica      Read more         Source

Fri, 08 Jun 2007 23:08:04 GMT

Oldest Mushroom ‘with Parasites’ in 100-million-year-old Amber Piece

Compared to the mushroom fossils known, a 20-million-year oldehas been found embedded in a 100-million-year-old piece of amber, making it the oldest ever found.

What interests the Oregon scientists, besides the mushroom itself, are the two parasites found in the ancient mushroom! One of these parasites is found to have been feeding on the mushroom and the other on its fellow parasite.

George Poinar, a retired entomology professor in Corvallis said,

I was amazed enough with the mushroom. But then seeing the parasites was astonishing. No one has ever seen this three-tier association before.

This finding is important as ancient mushrooms lack bones or shells, helping very few of them to survive. This newly found ancient specimen is similar to pinwheel mushrooms that grow on the bark of modern trees.

Mushroom fossils being rare, this amber discovery proves significant for entomologists. Thus, the oldest and the rare find of the mushroom come as a bonus with the two parasites inside it.
Image Posted by: Irani      Read more     Source

Fri, 08 Jun 2007 23:03:38 GMT

Liriodendron tulipifera

Thank you to arnaut from Alphen aan den Rijn, The Netherlands for today's photograph shared via this thread on the UBC forums.

Tulip tree is native to the hardwood forests of eastern North America. The Silvics of North America entry on Liriodendron tulipifera provides excellent information.

On a different note, BPotD and the garden web site will be down from 10pm tonight Vancouver time until 9am or so tomorrow morning. The building hosting the web server is undergoing more electrical upgrades, so the server will be shut down.

Botany resource link: More photographs from the recent Botany BC conference in Osoyoos, BC are now available on Ian Cumming's Photos of Hiking and Wildflowers. I've linked to Ian's page before, but considering the recent series of photos on BPotD from my trip to the conference, I thought I'd point out Ian's far more comprehensive pages for you to enjoy. Posted by: Daniel Mosquin      Read more     Source

June 6, 2007, 9:54 PM CT

Organic Food Miles take toll on environment

Organic fruit and vegetables may be healthier for the dinner table, but not necessarily for the environment, a University of Alberta study shows.

The study, conducted by a team of student scientists in the Department of Rural Economy at the University of Alberta in Edmonton, Canada, showed that the greenhouse gas emitted when the produce is transported from great distances mitigates the environmental benefits of growing the food organically.

If youre buying green, you should consider the distance the food travels. If its travelling further, then some of the benefits of organic crops are cancelled out by extra environmental costs, said researcher Vicki Burtt.

Burtt and her fellow scientists compared the cost of food miles between organic and conventionally grown produce, and observed that there was little difference in the cost to the environment.

Food miles are defined as the distance that food travels from the field to the grocery store. The study observed that the environmental cost of greenhouse gas (CO2) emitted to transport 20 tonnes of organically grown produce was comparable to that of bringing the same amount of conventional fruit and vegetables to market.

For the study, the team collected retail price data from six grocery stores and interviewed suppliers about their shipping methods. They created comparable food baskets of both organic and conventionally-grown fruit and vegetables being transported to Edmonton stores by truck, train or ship, and observed that most travels by truck. Since 1970 truck shipping has increased, replacing more energy-efficient rail and water transport......... Posted by: Erica      Read more         Source