September 18, 2008, 9:09 PM CT

Walnut Trees Emit Aspirin-Like Chemical to Deal With Stress

Walnut trees respond to stress by producing significant amounts of a chemical form of aspirin, researchers have discovered.

The finding, by researchers at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., opens up new avenues of research into the behavior of plants and their impacts on air quality, and also has the potential to give farmers an early warning signal about crops that are failing.

"Unlike humans, who are advised to take aspirin as a fever suppressant, plants have the ability to produce their own mix of aspirin-like chemicals, triggering the formation of proteins that boost their biochemical defenses and reduce injury," says NCAR scientist Thomas Karl, who led the study. "Our measurements show that significant amounts of the chemical can be detected in the atmosphere as plants respond to drought, unseasonable temperatures, or other stresses".

For years, researchers have known that plants in a laboratory may produce methyl salicylate, which is a chemical form of acetylsalicylic acid, or aspirin. But scientists had never before detected methyl salicylate in an ecosystem or verified that plants emit the chemical in significant quantities into the atmosphere.

The team of researchers reported its findings last week in the journal Biogeoscience. The research was funded by the National Science Foundation (NSF), NCAR's sponsor......... Posted by: Erica      Read more         Source

Wed, 17 Sep 2008 03:57:10 GMT

Jovellana punctata

Thanks again to Ruth for today''s write-up:

Found natively from low altitudes and the interior valleys of southern Chile (the humid matorrales or transitional woodlands), Jovellana punctata is a beautiful species in the Calceolariaceae. Its genus, Jovellana, is also found in New Zealand, displaying a wide southern hemispheric distribution.

Known in Chile as argenita or capachito, Jovellana punctata is a shrubby plant. It has large simple leaves with serrate margins. There is little research done on this species, but as a student of botany I can say that the spots on the carolla tube (fused petals) are set up as a "landing pad" for pollinators. Just like airports and rooftops use an "H" for helipads, flowers use colours and spot patterns to direct traffic. The bright yellow spots invite bees and birds to have a look inside, tricking them to spread pollen to the female parts.

The family Calceolariaceae was only recently separated from the Scrophulariaceae. It contains only two genera: Jovellana and Calceolaria.

Thanks for the second day in a row to J.G. in S.F.@Flickr for contributing an awe-inspiring photograph to BPotD (original | BPotD Flickr Group Pool)! Posted by: Daniel Mosquin      Read more     Source

August 31, 2008, 8:54 PM CT

Key discovered to cold tolerance in corn

Demand for corn -- the world's number one feed grain and a staple food for a number of -- is outstripping supply, resulting in large price increases that are forecast to continue over the next several years. If corn's intolerance of low temperatures could be overcome, then the length of the growing season, and yield, could be increased at present sites of cultivation and its range extended into colder regions.

Drs. Dafu Wang, Archie Portis, Steve Moose, and Steve Long in the Department of Crop Sciences and the Institute of Genomic Biology at the University of Illinois may have made a breakthrough on this front, as published in the recent issue of the journal Plant Physiology. .

Plants can be divided into two groups based on their strategy for harvesting light energy: C4 and C3. The C4 groups include a number of of the most agriculturally productive plants known, such as corn, sorghum, and sugar cane. All other major crops, including wheat and rice, are C3. C4 plants differ from C3 by the addition of four extra chemical steps, making these plants more efficient in converting sunlight energy into plant matter.

Until recently, the higher productivity achieved by C4 species was believed to be possible only in warm environments. So while wheat, a C3 plant, may be grown into northern Sweden and Alberta, the C4 grain corn cannot. Even within the Corn Belt and despite record yields, corn cannot be planted much before early May and as such is unable to utilize the high sunlight of spring......... Posted by: Erica      Read more         Source

August 25, 2008, 10:01 PM CT

Research breeder develops drought-tolerant corn

At the end of the day, drought tolerance in corn has to equate to good yields and good quality, not just good looks, said a Texas AgriLife Research scientist.

Dr. Wenwei Xu, AgriLife Research corn breeder from Lubbock, is working with crosses between temperate and tropically adapted varieties of corn to find a drought-tolerant plant that performs well under reduced irrigation.

"With the continuing decline of the Ogallala Aquifer water level and increasing cost of pumping water, the use of drought-tolerant and high-yield corn hybrids is a key for sustainable corn production under limited irrigation," Xu said.

A field day was held recently at the North Plains AgriLife Research Station near Etter to demonstrate the differences between the parent plants and the offspring, or crosses.

"We hope to reduce the amount of water mandatory for corn by at least 10 percent," Xu said.

Already the AgriLife Research program out of Lubbock has released four inbred lines of corn and numerous others are in the process for release, he said.

"The new multiple-stress-tolerant corn lines can be used to produce corn hybrids adapted to Texas and other southern states," Xu said. "They can be a powerful tool to save water and produce crops with yield and grain quality under stressful environments"......... Posted by: Erica      Read more         Source

August 21, 2008, 8:36 PM CT

Tahitian vanilla originated in Maya forests

The origin of the Tahitian vanilla orchid, whose cured fruit is the source of the rare and highly esteemed gourmet French Polynesian spice, has long eluded botanists. Known by the scientific name Vanilla tahitensis, Tahitian vanilla is found to exist only in cultivation; natural, wild populations of the orchid have never been encountered.

Now, a team of researchers led by Pesach Lubinsky, a postdoctoral researcher with Norman Ellstrand, a professor of genetics in UC Riverside's Department of Botany and Plant Sciences, claims to have traced Tahitian vanilla back to its true origins.

In the recent issue of the American Journal of Botany, Lubinsky and his colleagues use genetic and ethnohistoric analysis to argue that Tahitian vanilla began its evolutionary journey as a pre-Columbian Maya cultivar inside the tropical forests of Guatemala.

"All the evidence points in the same direction," Lubinsky said. "Our DNA analysis corroborates what the historical sources say, namely, that vanilla was a trade item brought to Tahiti by French sailors in the mid-19th century. The French Admiral responsible for introducing vanilla to Tahiti, Alphonse Hamelin, used vanilla cuttings from the Philippines. The historical record tells us that vanilla which isn't native to the Philippines was previously introduced to the region via the Manila Galleon trade from the New World, and specifically from Guatemala"......... Posted by: Erica      Read more         Source

July 22, 2008, 8:28 PM CT

Measuring the stress of forested areas

Plants undergo stress because of lack of water, due to the heat or the cold or to excess of light. A research team from the University of the Basque Country have analysed the substances that are triggered in plants to protect themselves, with the goal of choosing the species that is best suited to the environment during reforestation under adverse environmental conditions.

Droughts, extreme temperatures, contamination, and so on - all are harmful to plants. On occasions, the damage is caused by humans. For example, as a consequence of cutting down trees, plants used to shady conditions may be exposed to an excess of light. However, in most cases it is nature itself that causes the stress. In spring, plants have sufficient average humidity and temperatures, i.e. what researchers deem 'optimum conditions'. But in winter they have to withstand considerable cold and in summer, conversely, high temperatures and droughts: adverse environmental factors that generate stress situations. Thus, in winter and in summer, the light which under normal conditions would be a source of energy becomes excessive, given that the metabolism of the plants under these conditions is not able to assimilate it. This process is known as photo-oxidative stress.

Some plants are incapable of withstanding this stress - unable to dissipate the excess energy, generating a chain reaction by which they deteriorate and die. Other species, conversely, undergo processes of acclimatising themselves to the new situation and trigger chemical compounds that act to protect them. These species are the object of interest of a research team from the Department of Plant Biology and Ecology at the Faculty of Science and Technology of the University of the Basque Country (UPV/EHU). The members of this team - called EKOFISKO and led by Dr. Txema Becerril - are studying the plants' defence mechanisms in order to predict damage before it is produced. They measure the photo-protector substances created by the plants and analyse their behaviour, using them as biosensors of photo-oxidative stress......... Posted by: Erica      Read more         Source

July 22, 2008, 7:50 PM CT

Environmental factors linked to sex ratio of plants

Environmental factors can transform the ratio of females to males in plant populations as per new research out of the University of Toronto.

The study conducted by Ivana Stehlik, a lecturer, Jannice Friedman, a PhD candidate, and Spencer Barrett, a professor, involved a novel approach using genetic markers (known DNA sequences) to identify the sex of seeds. The team investigated six natural populations of the wind-pollinated herb Rumex nivalis in the Swiss Alps and mapped the distance between females and neighbouring males. They then measured the amount of pollen captured by female flowers and collected seeds from the plants when they were mature.

"The plant has strongly female-biased flowering sex ratios in these populations. We wanted to find out the mechanism causing the bias," said Barrett. "We observed that where there were more males surrounding females, females captured more pollen, matured more seed and produced more strongly female-biased offspring".

The authors suggest that when females capture large amounts of pollen, female-determining pollen tubes out-compete male-determining pollen tubes to fertilize the single ovule in each flower.

Barrett leads a world-renowned research group working on the genetics and evolution of plant reproduction. His pioneering work has had a profound influence on the understanding of biological invasions, weed management strategies and conservation biology. "Our results demonstrate for the first time that demographic aspects of the mating environment of plants can influence the sex ratios of plants females produce," added Barrett......... Posted by: Erica      Read more         Source

Sun, 20 Jul 2008 22:16:59 GMT

30 Creepiest Trees On Earth

If you are a horror movie buff, you''ve certainly noticed the liberal use of trees to set the mood. Halloween is hardly complete without the image of a moon-lit and fog-laden tree.

However, some trees have been molded by Mother Nature into specters of their own. Scary, frightening, or downright weird, these trees will leave you wondering if Mother Nature herself digested some magic mushrooms.

(thanks Chris) Posted by: Gerard      Read more     Source

July 17, 2008, 9:30 PM CT

Good breeding increases shelf life

The lettuce cut and packaged for food service and salad mixes is an increasingly important component of the produce industry. Lettuce is highly perishable, and the cutting mandatory in processing further shortens its shelf life.

Packaging cut lettuce and other fresh produce in semipermeable plastic films extends shelf life via a technique called "modified-atmosphere packaging". The success of modified-atmosphere (MA) packaging for lettuce and certain salad greens has led to innovative products, marketing strategies, and enhanced sales to consumers.

Increased demand for the convenient, pre-cut salads and lettuce has led to researchers to search for ways to select lettuce cultivars that stay fresh, colorful, and crisp. Shelf life and visual quality of salad-cut lettuce are affected by a number of things, including production environment, vegetative maturity, and type of lettuce chosen. Eventhough an increasing variety of lettuce types are being grown, romaine and "crisphead" (such as iceberg) are the most widely produced for salad-cut products.

Ryan J. Hayes, a research geneticist, and Yong-Biao Liu, research entomologist at the U.S. Department of Agriculture's Agricultural Research Service, published the results of a study that should give lettuce breeders and producers enhanced product information and a market edge. During the two-year study, lettuce was processed from field-grown plants of 33 romaine and three "crisphead" cultivars. Shelf life of each cultivar was reviewed after storage in modified-atmosphere bags and in CO₂-free controlled-atmosphere chambers......... Posted by: Erica      Read more         Source

July 15, 2008, 10:10 PM CT

Pollination Habits of Endangered Texas Rice

A type of wild rice that only grows in a small stretch of the San Marcos River is likely so rare because it plays the sexual reproduction game poorly, a study led by the Lady Bird Johnson Wildflower Center at The University of Texas at Austin has revealed.

The first study of breeding habits of this endangered, aquatic grass (Zizania texana) observed that the pollen of Texas wild-rice can only travel about 30 inches away from a parent plant. If pollen doesn't land on a receptive female flower within that distance, no seeds will be produced. No seeds means no new plants to replenish a population that faces other survival threats.

"It would be great to introduce more of these plants into the San Marcos River so that we can build up its population, said Flo Oxley, conservation director at the Wildflower Center, and lead author of the study.

"This information will be useful when reintroduction efforts begin, because we now know that lots of new plants must be planted close together in order for seeds to be produced".

The findings were published in June in The Southwestern Naturalist journal of the Southwestern Association of Naturalists, and shared with staff at the U.S. Fish and Wildlife Service and the Texas Parks and Wildlife Department.

The U.S. Fish and Wildlife Service is the principal federal agency responsible for federally listed species conservation. Texas has about 25 percent of the plant biodiversity nationally, including 23 endangered and five threatened plant species......... Posted by: Erica      Read more         Source