October 31, 2008, 5:24 AM CT

"Living fossil" tree contains genetic imprints

A "living fossil" tree species is helping a University of Michigan researcher understand how tropical forests responded to past climate change and how they may react to global warming in the future.

The research appears in the recent issue of the journal Evolution.

Symphonia globulifera is a widespread tropical tree with a history that goes back some 45 million years in Africa, said Christopher Dick, an assistant professor of ecology and evolutionary biology who is lead author on the paper. It is unusual among tropical trees in having a well-studied fossil record, partly because the oil industry uses its distinctive pollen fossils as a stratigraphic tool.

About 15 to 18 million years ago, deposits of fossil pollen suggest, Symphonia suddenly appeared in South America and then in Central America. Unlike kapok, a tropical tree with a similar distribution that Dick also has studied, Symphonia isn't well-suited for traveling across the ocean-its seeds dry out easily and can't tolerate saltwater. So how did Symphonia reach the neotropics? Most likely the seeds hitched rides from Africa on rafts of vegetation, as monkeys did, Dick said. Even whole trunks, which can send out shoots when they reach a suitable resting place, may have made the journey. Because Central and South American had no land connection at the time, Symphonia must have colonized each location separately......... Posted by: Erica      Read more         Source

October 27, 2008, 5:39 AM CT

Fried purple tomatoes

Researchers have expressed genes from snapdragon in tomatoes to grow purple tomatoes high in health-protecting anthocyanins.

Anthocyanins are naturally occurring pigments found at especially high levels in berries such as blackberry, cranberry and chokeberry. Researchers are investigating ways to increase the levels of health-promoting compounds in more usually eaten fruits and vegetables.

"Most people do not eat 5 portions of fruits and vegetables a day, but they can get more benefit from those they do eat if common fruit and veg can be developed that are higher in bioactive compounds," says Prof Cathie Martin from the John Innes Centre.

Anthocyanins offer protection against certain cancers, cardiovascular disease and age-related degenerative diseases. There is evidence that anthocyanins also have anti-inflammatory activity, promote visual acuity and hinder obesity and diabetes.

Tomatoes already contain high levels of the antioxidant lycopene. Highly processed tomatoes are the best source, or tomatoes cooked in a little oil, which helps to release the lycopene from cells. Flavonoids meanwhile are soluble in water, and foods containing both water soluble and fat-dissolved antioxidants are considered to offer the best protection against disease......... Posted by: Erica      Read more         Source

October 23, 2008, 8:55 PM CT

Diversity of trees in Ecuador's Amazon

Trees in a hyper-diverse tropical rainforest interact with each other and their environment to create and maintain diversity, scientists report in the Oct. 24 issue of the journal Science This study was conducted in the Yasuni forest dynamics plot of the Pontificia Universidad Catlica del Ecuador, the most diverse tropical forest site linked to the Center for Tropical Forest Science/Smithsonian Institution Global Earth Observatory network (CTFS/SIGEO).

It is difficult to determine the effects of climate change, habitat fragmentation and species extinctions on life's diversity without a coherent model of how communities are organized; but a unified theory of diversity patterns in ecological communities remains elusive. The most complex biological systemssuch as tropical rainforestsare the most important testing grounds for theories that attempt to generalize across ecological communities; as they pose the greatest challenge. At Yasuni, in addition to the 600 species of birds and 170 of mammals, there are approximately 1,100 species of trees in the 25 hectare plot―more than in all of the U.S. and Canada, combined.

In 2001 Stephen Hubbell, a scientist at the Smithsonian Tropical Research Institute and professor at the University of California, Los Angeles proposed a neutral theory of biodiversity based on more than 20 years of data from the original long-term forest dynamics plot on Barro Colorado Island, which he co-founded in 1980. The methods that Hubbell and colleagues at the Smithsonian established to study tropical forests in Panama were so useful that other institutions worldwide adopted the same methodologies. The plot in Ecuador was established in 1995 by scientists from the Universidad Catolica, Aarhus University in Denmark and the Smithsonian in Panama......... Posted by: Erica      Read more         Source

October 20, 2008, 10:07 PM CT

Current mass extinction spurs major study of which plants to save

The Earth is in the midst of the sixth mass extinction of both plants and animals, with nearly 50 percent of all species disappearing, researchers say.

Because of the current crisis, biologists at UC Santa Barbara are working day and night to determine which species must be saved. Their international study of grassland ecosystems, with flowering plants, is published this week in the Proceedings of the National Academy of Sciences

"The current extinction event is due to human activity, paving the planet, creating pollution, a number of of the things that we are doing today," said co-author Bradley J. Cardinale, assistant professor of ecology, evolution and marine biology (EEMB) at UC Santa Barbara. "The Earth might well lose half of its species in our lifetime. We want to know which ones deserve the highest priority for conservation".

He explained that the last mass extinction near the current level was 65 million years ago, called the Cretaceous Tertiary extinction event, and was probably the result of a meteor hitting the Earth. It is best known for the extinction of non-avian dinosaurs, but massive amounts of plant species became extinct at that time as well.

As per the current study, the most genetically unique species are the ones that have the greatest importance in an ecosystem. These are the ones that the researchers recommend be listed as top priority for conservation......... Posted by: Erica      Read more         Source

October 15, 2008, 5:35 PM CT

Creation of a new type of seed bank

(Santa Barbara, Calif.) While an international seed bank in a Norwegian island has been gathering news about its agricultural collection, a group of U.S. researchers has just published an article outlining a different kind of seed bank, one that proposes the gathering of wild species at intervals in the future effectively capturing evolution in action.

In the recent issue of Bioscience, Steven J. Franks of Fordham University, Susan J. Mazer of the University of California, Santa Barbara, and a group of colleagues, have proposed a method of collecting and storing seeds of natural plant populations. They argue for the collection of a number of species in a way that evolutionary responses to future changes in climate can be detected. They call it the "Resurrection Initiative".

"In contrast to existing seed banks, which exist primarily for conservation, this collection would be for research that would allow a greater understanding of evolution," said Franks.

"This seed collection would form an important resource that can be used for a number of types of research, just as GenBank the collection of genetic sequences and information forms a key resource for research in genetics and genomics," said Franks.

"Typically, seed banks are focused on the preservation of agricultural species or other plant species of strong economic interest, say, forest species, forest trees," said Mazer. This is to make sure that researchers can maintain a genetically diverse seed pool in the event of some kind of ecological calamity that requires the replenishing of seeds from a certain part of the world or from certain species. "But that implies a relatively static view of a seed bank, a snapshot forever of what a species provides"......... Posted by: Erica      Read more         Source

Tue, 07 Oct 2008 03:21:21 GMT

Pinus aristata

Ruth is again responsible for today''s write-up:

In keeping with our gymnosperm theme, it is appropriate to mention that the oldest-living known organism is a gymnosperm, an approximately 4,789 years old individual of the species Pinus longaeva. It has been named "Methuselah" after the oldest living person in the Bible. Methuselah resides in the White Mountains of California. Pinus longaeva is one of three pine species in a group called the bristlecone pines: Pinus longaeva, Pinus aristata and Pinus balfouriana.

Today''s photos are of Pinus aristata, also known as the Rocky Mountain bristlecone pine. It is found in Colorado, New Mexico and Arizona. Douglas Justice, the acting director of UBC Botanical Garden, took these pictures in the Mount Goliath Natural Area of Colorado. Thanks Douglas! These trees were growing at an altitude of 3300m (11000 ft), within the typical elevation where Pinus aristata can be found: 2500-3700 meters (8,000-12,000 feet). As you can imagine, these are cold, dry, subalpine conditions at or near tree-line.

One critical step in identifying any pine is to count the number of needles per fascicle (the fascicle is the tissue that holds needles together at the base of a cluster). This species maintains five stout needles per fascicle, and, unlike the other bristlecone pines, it typically has only one resin canal. According to the Wikipedia article on Rocy Mountains bristlecone pine, the resin canals are "commonly interrupted and broken....which looks a bit like ''dandruff'' on the needles."

Unlike Pinus longaeva, Pinus aristata rarely lives over 1,500 years. The oldest individual of Pinus aristata was found to be 2,435 years old growing on Mount Evans in Colorado. If you ever venture out to visit any of the three bristlecone pine species, take note that although they might be sparsely foliated, they are still alive. Often they will have only a thin strip of live tissue running along the gnarled tortured trunk connecting the leaves to the roots. These phenomenal trees have a strong dense and resinous wood that develops very slowly and defends the trees from pests. The Rocky Mountain bristlecone pine can be found in cultivation and makes a decent slow-growing tree for the home garden. Posted by: Daniel Mosquin      Read more     Source

October 2, 2008, 5:08 AM CT

Structures of Important Plant Viruses Determined

Flexible filamentous viruses make up a large fraction of known plant viruses and are responsible for more than half the viral damage to crop plants throughout the world. New details of their structures, which were poorly understood, have been revealed by researchers using a variety of sophisticated imaging techniques at the U.S. Department of Energy's Brookhaven National Laboratory and collaborating institutions.

These findings, just reported in the October 1, 2008, issue of the Journal of Virology, may lead to new ways to protect crop plants from viruses and other forms of damage. The structural information may also benefit researchers interested in using viruses as agents of biotechnology to coax plants to produce other useful products, such as pharmaceuticals.

"These are very important viruses, and we knew almost nothing about their detailed structure before these studies," said Gerald Stubbs, a structural biologist at Vanderbilt University and lead author on the paper. "If you are to come up with any molecular way of combating these plant diseases, you need to know the details of their structures." For example, structural information could help researchers design molecules that interfere with the virus's ability to infect plant cells.

The researchers from Vanderbilt, Brookhaven, Boston University, Illinois Institute of Technology, and the University of Kentucky studied the structures of two plant viruses from unrelated families, the Potyviridae and Flexiviridae, using a combination of complementary imaging techniques - x-ray diffraction at DOE's Argonne National Laboratory, cryo-electron microscopy at Vanderbilt, and scanning transmission electron microscopy (STEM) at Brookhaven......... Posted by: Erica      Read more         Source

October 1, 2008, 8:30 AM CT

Green coffee-growing practices buffer climate-change impacts

Chalk up another environmental benefit for shade-grown Latin American coffee: University of Michigan scientists say the technique will provide a buffer against the ravages of climate change in the coming decades.

Over the last three decades, a number of Latin American coffee farmers have abandoned traditional shade-growing techniques, in which the plants are grown beneath a diverse canopy of trees. In an effort to increase production, much of the acreage has been converted to "sun coffee," which involves thinning or removing the canopy.

Shade-grown farms boost biodiversity by providing a haven for birds and other animals. They also require far less synthetic fertilizer, pesticides and herbicides than sun-coffee plantations.

In the October edition of the journal BioScience, three U-M scientists say shade-growing also shields coffee plants during extreme weather events, such as droughts and severe storms. Climate models predict that extreme weather events will become increasingly common in the coming decades, as the levels of heat-trapping carbon dioxide gas continue to mount.

The U-M researchers warn Latin American farmers of the risks tied to "coffee-intensification programs"---a package of technologies that includes the thinning of canopies and the use of high-yield coffee strains that grow best in direct sunlight---and urge them to consider the greener alternative: shade-grown coffee......... Posted by: Erica      Read more         Source

September 28, 2008, 8:40 PM CT

Gene that may contribute to improved rice yield

A team of scientists, including Penn State Distinguished Professor of Biology Hong Ma, has identified a gene in rice that controls the size and weight of rice grains. The gene may prove to be useful for breeding high-yield rice and, thus, may benefit the vast number of people who rely on this staple food for survival. "Our work shows that it is possible to increase rice's yield by enhancing the expression of a particular gene," said Ma. The team's results will be published on 28 September 2008 in an early online edition of the journal Nature Genetics, and in the November print issue of the journal.

The scientists first searched for and identified mutant strains of rice that exhibited underweight grains. "We found a particular mutant that is defective in its ability to produce normal-sized grains," said Zuhua He, a biology professor at the Chinese Academy of Sciences and the leader of the team. The group then examined the mutant and observed that it carried a mutation within the GIF1 gene. "The GIF1 gene is responsible for controlling the activity of the enzyme invertase, which is located in the cell wall and converts sucrose to substances that then are used to create starch," said He. "Invertase is important in the formation of starch within developing grains of rice. If invertase is not active, the rice plant cannot produce edible grains"......... Posted by: Erica      Read more         Source

September 18, 2008, 9:56 PM CT

GenesControlling Rhythmic Plant Growth

A team of biologists from UC San Diego, the Salk Institute for Biological Studies and Oregon State University has identified the genes that enable plants to undergo bursts of rhythmic growth at night and allow them to compete when their leaves are shaded by other plants.

The scientists report in this week's issue of the journal PLoS Biology that these genes control the complex interplay of plant growth hormones, plant light sensors and circadian rhythms that permit plants to undergo rhythmic growth spurts at specific times of the day or year in response to varying levels of light and other environmental conditions.

Their discovery of the genetic underpinnings of the rhythmic plant movements that enthralled Charles Darwin more than a century ago could eventually allow researchers to design crops that can grow substantially faster and produce more food than the most productive varieties today.

"This paper builds on our prior findings that almost all plant genes are expressed only at a particular time of the day," said Howard Hughes Medical Institute investigator Joanne Chory, a professor in the Salk Institute's Plant Biology Laboratory.

"What we found is a whole raft of genes that could be the actual molecular switches that define plant growth at the molecular level," said Steve Kay, Dean of the Division of Biological Sciences at UC San Diego and one of the leaders of the research team. "The more we understand about these genetic mechanisms and how they switch on and off plant growth, the better we will be at designing tailor-made crops to increase our production of food and fuel for the world's rapidly growing population"......... Posted by: Erica      Read more         Source