March 9, 2008, 5:14 PM CT

Signaling pathway for better biofuel sources

A newly defined biochemical pathway in plants may provide the scientific tools to design plants that will yield larger quantities of alternative transportation fuels than currently can be produced, as per Purdue University researchers.

The pathway moves materials that determine cell shape and size through a system of signaling proteins, said Dan Szymanski, a plant geneticist and cellular biologist. By learning more about the growth and development process, it may be possible to engineer plants with improved properties such as cell walls that are more massive or are more easily fermented in the biofuel process.

"We expect that cell wall material will be a major source of biomass from plants designated for biofuel production," Szymanski said. "We need to learn more about how plant cells control the quality and amount of cell wall material".

He and his research team investigated plant growth and cell wall development from several scientific approaches in determining the cascade of events that leads to changes in the cell wall. They discovered that a protein called "SPIKE1" directs the protein signaling pathway. They report their findings in "Early Edition," the online publication of the journal Proceedings of the National Academy of Sciences. The study also would be reported in the journal's March 11 print issue......... Posted by: Erica      Read more         Source

March 9, 2008, 4:39 PM CT

Why pears may become brown during commercial storage

Internal browning of pears stored under low oxygen conditions is correlation to restricted gas exchange inside the fruit, as per a research studypublished March 7th in the open-access journal PLoS Computational Biology. Scientists at the Catholic University of Leuven in Belgium suggest a computer model that can be used to improve long-term storage of fruit under controlled atmospheres.

Pears and other fleshy fruit are commercially stored under low oxygen conditions to extend their storage life for up to 9 months. If the oxygen concentration in the storage atmosphere is too low, quality disorders such as internal browning may result, causing major economic losses. This disorder is known to be correlation to the complex mechanisms of gas exchange, respiration and fermentation in fruit. However, further conclusions are unavailable due to the lack of reliable methods to measure gas concentrations inside the fruit.

The team, led by Bart Nicola, has developed a comprehensive computer model to predict the oxygen concentration inside the pear. The model incorporates equations for gas transport as well as for the respiratory metabolism. The scientists observed that extremely low oxygen concentrations can occur in the core of the pear, which eventually may lead to cell death and browning......... Posted by: Erica      Read more         Source

March 5, 2008, 8:54 PM CT

Killer freeze of '07 illustrates paradoxes of warming climate

A destructive spring freeze that chilled the eastern United States almost a year ago illustrates the threat a warming climate poses to plants and crops, as per a paper just reported in the journal BioScience. The study was led by a team from the Department of Energy's Oak Ridge National Laboratory.

The "Easter freeze" of April 5-9, 2007, blew in on an ill wind. Plants had been sending out young and tender sprouts two to three weeks earlier than normal during an uncommonly warm March. Plant ecologists, as well as farmers and gardeners, took note of the especially harsh turn of the weather in early April.

"The warm weather was as much a culprit for the damage as the cold," said lead author Lianhong Gu of ORNL's Environmental Sciences Division.

"We see the paradox in that mild winters and warm, early springs make the plants especially vulnerable to late-season frosts," Gu said. Gu's team observed satellite images and field data to establish the extent of the 2007 spring freeze. They also assessed the long-term and short-term effects on the terrestrial carbon cycle with respect to plant activity in normal years. Short-term effects were "profound," Gu said.

"In the period just after the freeze we saw a large reduction in the fraction of absorbed photosynthetically active radiation, which is a sensitive indicator of plant growth," he said. "We also noted that the regrowth in the following weeks and months did not result in the levels of plant development in prior years."........ Posted by: Erica      Read more         Source

February 25, 2008, 9:03 PM CT

Draft sequence of corn genome

A team of researchers led by Washington University in St. Louis has begun to unlock the genetic secrets of corn, a crop vital to U.S. agriculture. The scientists have completed a working draft of the corn genome, an accomplishment that should accelerate efforts to develop better crop varieties to meet society's growing demands for food, livestock feed and fuel.

Corn, also known as maize, underlies myriads of products, from breakfast cereal, meat and milk to toothpaste, shoe polish and ethanol.

The genetic blueprint will be announced on Thursday, Feb. 28, by the project's leader, Richard K. Wilson, Ph.D., director of Washington University's Genome Sequencing Center, at the 50th Annual Maize Genetics Conference in Washington, D.C.

"This first draft of the genome sequence is exciting because it's the first comprehensive glimpse at the blueprint for the corn plant," Wilson says. "Researchers now will be able to accurately and efficiently probe the corn genome to find ways to improve breeding and subsequently increase crop yields and resistance to drought and disease."

The $29.5 million project was initiated in 2005 and is funded by the National Science Foundation (NSF), the U.S. Department of Agriculture and the U.S. Department of Energy. "Corn is one of the most economically important crops for our nation," says NSF director Arden L. Bement Jr. "Completing this draft sequence of the corn genome constitutes a significant scientific advance and will foster growth of the agricultural community and the economy as a whole."........ Posted by: Erica      Read more         Source

Wed, 13 Feb 2008 01:37:52 GMT

Sclerochiton odoratissimus

Thank you to Michael Charters of Calflora.net for contributing today''s photograph via the Botany Photo of the Day submissions forum on the garden''s site (in this thread). As Michael notes, “Here''s a picture of a beautiful species that has few if any images displayed on the internet”.

It''s not just images that are hard to come by online – information about the species is hard to find, too! Michael''s description, “It is an erect shrub 3-4'' tall, sparsely hairy all over and sweetly scented, hence the species name”, is about as much information as I can locate, though the Botanical Society of Africa''s Kwa Zulu-Natal Coastal Branch adds that it prefers semi-shade and has a common name of “white lips”.

Details about this genus of African woody plants are a bit easier to locate, thanks to the Flora of Zimbabwe''s entry on Sclerochiton and (especially) the Tree of Life''s page on Sclerochiton. The latter contains additional images of species in the genus, including the member of the genus most often (though still rarely) found in cultivation, Sclerochiton harveyanus (or “blue lips”, despite the colour of the flower in the image on that page). Swaziland''s Flora Database explains that Sclerochiton harveyanus may have a flower colour of mauve, purple or violet (and in shade, I suppose, these may appear blue, hence blue lips). Posted by: Daniel Mosquin      Read more     Source

February 6, 2008, 9:05 PM CT

Nitrogen pollution boosts plant growth

A study by UC Irvine ecologists finds that excess nitrogen in tropical forests boosts plant growth by an average of 20 percent, countering the belief that such forests would not respond to nitrogen pollution.

Faster plant growth means the tropics will take in more carbon dioxide than previously thought, though long-term climate effects are unclear. Over the next century, nitrogen pollution is expected to steadily rise, with the most dramatic increases in rapidly developing tropical regions such as India, South America, Africa and Southeast Asia.

Nitrogen fertilizer, applied to farmland to improve crop yield, also affects ecosystems downwind by seeping into runoff water and evaporating into the atmosphere. Industrial burning and forest clearing also pumps nitrogen into the air.

"We hope our results will improve global change forecasts," said David LeBauer, graduate student researcher of Earth system science at UCI and lead author of the study.

The research results appear in the recent issue of the journal Ecology.

Using data from more than 100 previously published studies, LeBauer and Kathleen Treseder, associate professor of ecology and evolutionary biology at UCI, analyzed global trends in nitrogen's effect on growth rates in ecosystems ranging from tropical forests and grasslands to wetlands and tundra. Nitrogen, they found, increased plant growth in all ecosystems except for deserts......... Posted by: Erica      Read more         Source

January 30, 2008, 9:18 PM CT

African fruits could help alleviate hunger

Africa's own fruits are a largely untapped resource that could combat malnutrition and boost environmental stability and rural development in Africa, says a new report from the National Research Council. African science institutes, policymakers, nongovernmental organizations, and individuals could all use modern horticultural knowledge and scientific research to bring these "lost crops" -- such as baobab, marula, and butterfruit -- to their full potential, said the panel that issued the report.

Today, tropical fruit production in Africa is dominated by species introduced from Asia and the Americas, such as bananas, pineapples, and papayas. Because these and other crops arrived on the continent centuries ago already improved through horticultural selection and breeding, they increasingly displaced the traditional species that had fed Africans for thousands of years. The imported species also received the support of colonial powers who wanted familiar crops that were profitable to grow, and indigenous fruits continued their downward spiral of dwindling cultivation and knowledge.

With renewed scientific and institutional support, however, Africa's native fruits could make a much greater contribution to nutrition and economic development, the new report says. Fruit trees and shrubs also offer long-term benefits by improving the stability of the environment......... Posted by: Erica      Read more         Source

January 29, 2008, 9:53 PM CT

Insects on coffee plants

Ever since a forward-thinking trio of physicists identified the phenomenon known as self-organized criticality-a mechanism by which complexity arises in nature-researchers have been applying its concepts to everything from economics to avalanches.

Now, scientists at the University of Michigan and the University of Toledo have shown that clusters of ant nests on a coffee farm in Mexico also adhere to the model. Their work, which has implications for controlling coffee pests, appears in the Jan. 24 issue of the journal Nature.

The basic idea of self-organized criticality often is illustrated with a sand pile. As you trickle sand onto the cone-shaped pile, the cone grows and grows until it reaches a "state of criticality" where it stops growing. Add more sand, and the grains just slide down the sides in mini-avalanches.

"What physicists have done-both mathematically and physically-is look at how a number of grains of sand actually fall with each avalanche," said John Vandermeer, the Margaret Davis Collegiate Professor of Ecology and Evolutionary Biology and one of the Nature paper's authors. "What they find is that most avalanches involve one or two sand grains, and relatively few avalanches involve hundreds of sand grains." Such a pattern-with small versions of a phenomenon being more common than big ones-characterizes what's known as a power law, a sort of fingerprint of systems that exhibit self-organized criticality......... Posted by: Kelly      Read more         Source

January 29, 2008, 9:33 PM CT

River plants may play major role in health of ocean

Recent research at MIT's Department of Civil and Environmental Engineering suggests how aquatic plants in rivers and streams may play a major role in the health of large areas of ocean coastal waters.

This work, which appeared in the Dec. 25 issue of the Journal of Fluid Mechanics (JFM), describes the physics of water flow around aquatic plants and demonstrates the importance of basic research to environmental engineering. This new understanding can be used to guide restoration work in rivers, wetlands and coastal zones by helping ecologists determine the vegetation patch length and planting density necessary to damp storm surge, lower nutrient levels, or promote sediment accumulation and make the new patch stable against erosion.

Professor Heidi Nepf is principle investigator on the research. Brian White, a former graduate student at MIT who is now an assistant professor at the University of North Carolina, is co-author with Nepf of the JFM paper. Marco Ghisalberti, a postdoctoral associate at the University of Western Australia, worked with Nepf on some aspects of this research when he was an MIT graduate student. This work was supported by grants from the National Science Foundation.

Traditionally people have removed vegetation growing along rivers to speed the passage of waters and prevent flooding. But in recent years that practice has changed. Ecologists now advocate replanting, because vegetation provides important habitat. In addition, aquatic plants and the microbial populations they support remove excess nutrients from the water. The removal of too a number of plants contributes to nutrient overload in rivers, which can subsequently lead to coastal dead zones-oxygen-deprived areas of coastal water where nothing can survive. One well-documented dead zone in the Gulf of Mexico, fed by nutrient pollution from the Mississippi River, grows to be as large as the state of New Jersey every summer......... Posted by: Erica      Read more         Source

January 28, 2008, 5:20 AM CT

Plant Gene that Affects Stress Resistance

A University of Saskatchewan team of researchers has isolated a gene that has never before been identified in helping plants to resist stress.

The study-published this month in the top-ranked plant journal The Plant Cell-could pave the way for development of agricultural and forestry crops that are more tolerant to environmental stresses such as ultra-violet light and other types of radiation.

"Our next step is to see if plant genes we've isolated also play a similar role in fighting infections," said U of S microbiologist Wei Xiao. "In prior research, our team and others have shown that similar genes in human and animal cells play an important role in protection against both viral and bacterial infections".

In an unusual collaboration, Xiao teamed up with U of S biochemist Hong Wang, two post-doctoral fellows and three graduate students on the study. Doctoral student Rui Wen is the lead author on the paper.

Using Arabidopsis, a widely accepted research model plant closely correlation to canola, the team cloned and characterized four genes suspected of playing a role in the plant's stress responses. The team observed that when plants were subjected to a DNA-damaging stressor, the plants in which one of the four genes had been turned off produced seedlings that grew slower and often died, compared with a control group......... Posted by: Erica      Read more         Source