October 12, 2006, 7:54 PM CT

Plants Become Air Quality Detectives

What does a garden have to do with the chemistry of the atmosphere and air quality? One of the newest exhibits at NASA Goddard's Visitor Center, Greenbelt, Md., is a project correlation to NASA's Aura satellite. Aura is currently studying atmospheric chemistry and air pollution from space. The new Aura Ozone Monitoring Garden is used to study air quality from the ground by seeing how ozone in the air damages the leaves of certain plants.

During the summer months of intense sunlight, the air surrounding major urban areas undergoes dramatic changes. Ozone is formed when chemical pollutants that are by-products of human activities such as biomass burning and the combustion of fossil fuels react in the presence of sunlight. Ozone is a molecule that at ground level is a harmful air pollutant in high or prolonged concentrations.

Ozone tolerance among plants and people varies. As per research at the Great Smoky Mountain National Park and elsewhere, a number of common species of plants are sensitive to high concentrations of ozone. The Aura Ozone Monitoring Garden features plants that are known to be ozone sensitive, such as white dogwood (Cornus florida) and cardinal flower (Lobelia cardinalis).

A number of of the plants that have been found to be ozone sensitive thrive in a wide range of the temperate environments within the continental United States. Aura education personnel at Goddard chose a variety of plants for the garden that represent different growing environments, from agriculture to horticulture.........

Posted by: Erica      Permalink         Source

October 8, 2006, 6:48 PM CT

Rearing An Army To Save Wheat

With wheat stem sawfly natural enemies in demand, Montana State University entomologists are investigating ways of increasing their availability.

This fall, the entomologists are concluding a two-year study that involved mass-rearing parasitic wasps that attack wheat stem sawfly larvae that tunnel the interior of developing wheat plants. The team includes entomologists David Weaver, master's graduate Godshen Pallipparambil-Robert and undergraduate Melissa Frazier of Kalispell.

Pallipparambil-Robert's work, as part of his completed master's degree, used large cages placed over wheat at the Post Agronomy Farm west of Bozeman. He deliberately infested the enclosed wheat with wheat stem sawflies, and then introduced the parasitic wasps. His research explored whether supplemental food provided as nectar from flowering plants or as honey water increases the number of parasitic wasps produced in each cage. Another part of his thesis project examined whether using special ultraviolet and visible light-transmitting windows increases the number of parasites.

"After two years, the research shows that the added light consistently causes small increases in the number of parasitic wasps, while the food supply is probably not important in these mass-rearing cages, because the parasitoids were added in large numbers, and attacked the available sawflies before the need to feed may have become critical " Weaver said. At lower parasitoid densities, supplemental food might be much more important, and research from other systems suggests that this is definitely true in natural settings. However, the goal of the research is to find ways to increase the supply of parasitoids from a controlled system to Montana wheat growers.........

Posted by: Kelly      Permalink         Source

October 4, 2006, 10:10 PM CT

Tree Rings Provide A 200-year-old Hurricane Record

Researchers have shown that an age-old "database"--tree rings--contains surprisingly accurate information about hurricane activity that occurred hundreds of years ago. By measuring different chemical forms of oxygen present in the rings, scientists identified periods when hurricanes hit areas of the Southeast more than 100 years before modern records were kept.

The technique allows researchers to extend from decades to centuries the time-frames of intense hurricane cycles and may help determine if the increase in the number of hurricanes hitting the Southeast since the mid-1990s is part of a regularly occurring cycle or due to causes such as global climate change.

Their research is being reported in the Sept. 18, early online edition of the Proceedings of the National Academy of Sciences. It was funded by grants from the National Science Foundation and the University of Tennessee (UT).........

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October 4, 2006, 10:05 PM CT

Genome Info From "Plant Destroyers"

An international team of researchers has published the first two genome sequences from a destructive group of plant pathogens called Phytophthora--a name that literally means "plant destroyer." The more than 80 species of fungus-like Phytophthora (pronounced "fy-TOFF-thor-uh") attack a broad range of plants and together cost the agriculture, forestry and nursery industries hundreds of billions of dollars each year.

Even though Phytophthora are similar to fungi, most fungicides are ineffective at controlling them. The information gained from studying the genomic sequences of P. ramorum and P. sojae will help researchers devise strategies to combat not only these two species, but also other disease-causing Phytophthora.

The study appears in the Sept. 1 issue of the journal Science.

Phytophthora sojae, an endemic pathogen of soybeans, is responsible for $1 billion to $2 billion in losses worldwide each year. Phytophthora ramorum is linked to sudden oak death, a disease that has devastated the nursery industry and oak ecosystems in California, Oregon and Washington. More than 1 million native oak and tanoak trees have been lost to the disease.

In addition to soybean and oak, Phytophthora species cause disease in avocado, coconut, papaya, pineapple, potato, strawberry and watermelon, to name a few. The pathogen also destroys an estimated 450,000 tons of cocoa beans with a resulting $400 million loss in chocolate production each year.........

Posted by: Erica      Permalink         Source

October 4, 2006, 8:31 PM CT

Earlier Crop Plantings Could Curb Future Yields

In an ongoing bid to grow more corn, farmers in the U.S. Corn Belt are planting seeds much earlier today than they did 30 years ago, a new study has observed.

Poring over three decades of agricultural records, Christopher Kucharik, an associate scientist at the University of Wisconsin-Madison, discovered that farmers in 12 U.S. states now put corn in the ground around two weeks earlier than they did during the late 1970s. His findings are reported in the current issue of the Agronomy Journal.

Earlier plantings-which mean longer growing seasons--have likely contributed to the increasing corn yields of recent decades. But Kucharik, a terrestrial ecologist at the UW-Madison's Center for Sustainability and the Global Environment, warns the trend can only continue for so long.

"Earlier plantings really can't continue forever because ultimately, farmers will have to contend with wintertime conditions and frozen soils," says Kucharik. "Several decades from now we might see an unexpected drop in annual yield increases when this trend plateaus, which could then increase the threat to our food supply".

The Corn Belt is a major agricultural region of the U.S. Midwest, where corn is a dominant crop. Centered in Iowa and Illinois, the belt extends into Wisconsin, Michigan, Minnesota, South Dakota, Nebraska, Kansas, Missouri, Indiana, Ohio and Kentucky.........

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October 4, 2006, 8:22 PM CT

Light On Evolution Of Life Cycles

In the history of life on earth, one intriguing mystery is how plants made the transition from water to land and then went on to diversify into the array of vegetation we see today, from simple mosses and liverworts to towering redwoods.

A research team led by University of Michigan evolutionary biologist Yin-Long Qiu has new findings that help resolve long-debated questions about the origin and evolution of land plants. The work will be published online this week in the Proceedings of the National Academy of Sciences.

Two major steps kicked off the chain of events that helped land plants prosper, forming the basis for modern land-based ecosystems and fundamentally altering the course of evolution of life on earth, said Qiu. The first step was the colonization of land by descendents of aquatic plants known as charophyte algae. That event opened up a vast new world where the sun's intensity was undiminished by passage through water and where carbon dioxide-another essential ingredient for plant life-was abundant.

The second event was a key change in plant life cycles. Plants exhibit a phenomenon known as alternation of generations, in which two alternating forms with different amounts of DNA make up a complete life cycle. One form, known as a sporophyte, produces spores, which grow into individuals of the other form, called gametophytes. Gametophytes produce gametes-eggs and sperm-which unite to form a fertilized egg capable of becoming a new sporophyte, thus completing a life cycle. While all plants exhibit alternation of generations, some spend most of their life cycle as sporophytes, and others spend more time in the gametophyte phase.........

Posted by: Erica      Permalink         Source

October 4, 2006, 4:34 AM CT

Morganella Pyriformis

Morganella pyriformis is a puffball. The mature fruiting body of the fungus bursts open and releases the spores, after some physical force has been applied. I've been known to help a few of these along.

Previous to 2003, this fungus was known as Lycoperdon pyriforme. It has since been moved out of the genus Lycoperdon based on molecular evidence and morphological difference to other members of the genus. No longer is the evocative common name suggested by Tom Volk a literal translation of the genus name. A different common name, pear-shaped puffball, is perhaps more proper. After all, the epithet pyriformis does mean "in the form of Pyrus (pear)". However, I'll personally use the one proposed by Tom, because I know I'll never forget it.

Tom's article also has a story about the results of deeply inhaling the spores of puffballs (don't do it). Illustrations and descriptions of Morganella pyriformis are available from both Mykoweb and Michael Kuo's MushroomExpert.com.........

Posted by: Erica      Permalink         Source

October 2, 2006, 10:10 PM CT

How did bilaterally symmetric flowers evolve?

How did bilaterally symmetric flowers evolve from radially symmetric ones? To address this important question, geneticists Francisco Perfectti and Juan Pedro M. Camacho, and ecologist Jos M. Gmez (Universidad de Granada, Spain) explored how different flower shapes affected plant fitness in natural populations of Erysimum mediohispanicum, a Mediterranean herb. Their findings would be reported in the recent issue of The American Naturalist.

The scientists observed that plants bearing bilaterally symmetrical flowers were more visited by pollinators and had higher fitness, measured by both the number of seeds produced per plant and the number of seeds surviving to the juvenile stage, than plants with radially symmetric flowers.

"This study reveals that natural selection can play a key role in the evolution of flower bilateral symmetry," says Camacho. "Our data also suggest that it is possible to understand the evolution of complex forms by means of microevolutionary analyses, as complementary tools to those coming from developmental genetics".........

Posted by: Erica      Permalink         Source

October 1, 2006, 8:37 PM CT

Questions About Gmos And Allergies

The potential of genetically engineered foods to cause allergic reactions in humans is a big reason for opposition to such crops. Eventhough protocols are in place to ask questions about the allergy-causing possibilities, there has been no test that offers definitive answers.

But all of that could change as a Michigan State University researcher has developed the first animal model to test whether genetically engineered foods could cause human allergic reactions. Venu Gangur, MSU assistant professor of food science and human nutrition, has received a $447,000 grant from the Environmental Protection Agency to validate the test.

Genetically engineered crops are created by inserting a protein from a different organism into the original crop's genome. This is commonly done to create a plant that is more resistant to insects or diseases.

The Food and Agriculture Organization within the World Health Organization has a structured approach to determining whether genetically engineered foods cause allergies, as per Gangur, who also is a faculty member in the National Food Safety and Toxicology Center. "But it has a major flaw. A critical question in that process asks, 'Does the protein cause an allergic reaction in animals?' The problem is that there has been no good animal model available to test this".........

Posted by: Erica      Permalink         Source

September 28, 2006, 9:30 PM CT

Live Oak Trees Struggle For Survival

The majestic live oak is losing its battle for survival to suburban sprawl and the encroachment of taller trees, a new University of Florida study finds.

An icon in American history and literature, broad-crowned live oaks thrive in open savannas but are dying off as they are crowded and overshadowed by the encroachment of taller trees, said Francis Putz, a UF botanist and the study's co-author.

It is an irony of nature that the successes of reforestation and urban forestry threaten live oaks, which in the past maintained the elbow room they needed from logging, cattle grazing and frequent fires, said Putz, whose work is reported in the recent issue of Forest Ecology and Management. "We are confusing our natural savanna heritage with forested landscapes and the tragedy is that the forest is killing live oaks," he said. "If we allow other trees to grow up too close to the live oak, the live oak will die. Our research clearly establishes this fate in both rural and suburban landscapes."

The live oak's broad crown, with long arching limbs that spread horizontally rather than vertically, as most trees do, give it a distinctive architectural makeup, said Tova Spector, who did the study with Putz as part of her master's degree in ecology. "Trees that grow straight and tall crowd the live oaks, causing their crowns to die back," she said.........

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