May 17, 2006, 11:46 PM CT

Photosynthetic Trends In Northern Circumpolar High Latitudes

Using time series analyses of a 22-year record of satellite observations across the northern circumpolar high latitudes, researchers at the Woods Hole Research Center are assessing trends in vegetation photosynthetic activity. The results indicate that tundra areas consistently and predominantly show greening trends while forested areas show browning, indicating that the boreal forest biome might be responding to climate change in previously unexpected ways. This research is highlighted in the current issue of Earth Interactions.

As per Andrew Bunn, lead author of the paper and a post-doctoral fellow at the Center, "This research suggests that the high latitudes might not be responding to climate change as previously thought. If the ability of boreal forests to capture and store carbon in a warmer world is not as great as we've previously supposed, then we will have to think differently about how the planet will respond to continuing emissions of carbon dioxide."

All land surfaces above 50 degree N, excluding the glaciers of Greenland, were included in this study. Growing seasons were defined as May to August though early and late growing season periods were also considered. Three primary data sets derived from polar-orbiting satellites were used.

Overall, tundra areas show marked greening over the entire growing season. These patterns were consistent with relatively simple climate response seen in related work in North America, where areas responded to summer maximum temperatures while the response of forest vegetation was more complex. Boreal forests patterns indicate significant greening in May and June, with gains offset by substantive browning in July and August.........

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May 16, 2006, 10:50 PM CT

How Plant Gets Protection From Cold?

In response to cold, plants trigger a cascade of genetic reactions that allow them to survive. University of California, Riverside Professor of Plant Cell Biology Jian-Kang Zhu has described how a little-known biochemical reaction regulates that genetic cascade.

Zhu's findings were reported in the May 15 online version of the Proceedings of the National Academy of Sciences in a paper titled The Negative Regulator of Plant Cold Responses, HOS1 is a RING E3 Ligase That Mediates the Ubiquitation and Degredation of ICE1. Zhu co-authored the paper with UCR colleagues Chun Hai Dong and Manu Agarwal; and Yiyue Zhang and Qi Xie, from the Institute of Genetics and Development of the Chinese Academy of Sciences in Beijing.

This negative regulator, known as high expression of osmotically responsive gene 1 (HOS1), acts essentially as a biochemical gate that cuts off the plant's cold protection, Zhu said. The HOS1 gene product interacts with another gene product known as ICE1 that kicks off the genetic cascade that provides the plant's cold protection proteins, as per the paper. The interaction worked both in the test tube and in the live plant.

"The better we understand this molecular mechanism, the better we can control the process of increasing the plant's freezing tolerance without causing negative impacts," Zhu said. "This process should apply to all plants and can help us better use crops of subtropical origin such as corn, rice, avocadoes and strawberries".........

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May 16, 2006, 0:07 AM CT

Global Warming May Have Damaged Coral Reefs Forever

Global warming has had a more devastating effect on some of the world's finest coral reefs than previously assumed, suggests the first report to show the long-term impact of sea temperature rise on reef coral and fish communities.

Large sections of coral reefs and much of the marine life they support may be wiped out for good, say the international team of researchers, who surveyed 21 sites and over 50,000 square metres of coral reefs in the inner islands of the Seychelles in 1994 and 2005.

Their report is the first to show the long-term impact of the 1998 event where global warming caused Indian Ocean surface temperatures to increase to unprecedented and sustained levels, killing off (or 'bleaching') more than 90 per cent of the inner Seychelles coral.

The team, led by the University of Newcastle upon Tyne, and which comprises scientists from the UK, Australia and the Seychelles, publishes its findings today, Monday May 15, in the Proceedings of the National Academy of Sciences.

The research showed that, while the 1998 event was devastating in the short term, the main long-term impacts are down to the damaged reefs being largely unable to reseed and recover. A number of simply collapsed into rubble which became covered by unsightly algae.........

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May 14, 2006, 3:49 PM CT

How did cactuses evolve?

In a groundbreaking new study in the recent issue of American Naturalist, Erika J. Edwards (Yale University and University of California, Santa Barbara) and Michael J. Donoghue (Yale University) explore how leafy, "normal" plants evolved into the leafless succulent cactus.

"The cactus form is often heralded as a striking example of the tight relationship between form and function in plants," write the authors. "A succulent, long-lived photosynthetic system allows cacti to survive periods of extreme drought while maintaining well-hydrated tissues."

Recent molecular phylogenetic work has confirmed that Pereskia, a genus that consists of 17 species of leafy shrubs and trees, is where the earliest cactus lineages began. Using field studies and environmental modeling, Edwards and Donoghue found that the Pereskia species already showed water use patterns that are similar to the leafless, stem-succulent cacti.

"[Our] analyses suggest that several key elements of cactus ecological function were established previous to the evolution of the cactus life form," explain the authors. "Such a sequence may be common in evolution, but it has rarely been documented as few studies have incorporated physiological, ecological, anatomical, and phylogenetic data."........

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May 10, 2006, 0:17 AM CT

Importance Of Fungi In Arctic Nitrogen Cycle

A new method to calculate the transfer of nitrogen from Arctic mushrooms to plants is shedding light on how fungi living symbiotically on plant roots transfer vital nutrients to their hosts. The analytical technique, developed by John E. Hobbie, MBL Distinguished Scientist and co-director of the laboratory's Ecosystems Center and his son, Erik A. Hobbie of the University of New Hampshire, may be applied to nearly all conifers, oaks, beeches, birch and shrubs such as blueberry and cranberry-all nitrogen-poor ecosystems-and will be an important tool for future studies of plant nitrogen supply.

It has long been known when soil nitrogen is in short supply, mycorrhizal fungi (those living symbiotically on the roots of plants) transfer nutrients to their host plants in exchange for plant sugars derived from photosynthesis, but the rates of transfer have never been quantified in the field. John and Erik Hobbie's study, reported in the April 2006 issue of the journal Ecology, quantifies the role.

of mycorrhizal fungi in nitrogen cycling for the first time through measurements of the natural abundance of nitrogen isotopes in soils, mushrooms and plants. The scientists tested their technique using data from the Arctic LTER (Long Term Ecological Research) site near Toolik Lake, Alaska, in the northern foothills of the Brooks Range.........

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May 8, 2006, 9:12 PM CT

Two New Varieties of Non-Allergenic Soybeans

Soy is also a very common ingredient in a lot of food products, usually as fillers and extenders. For a lot of vegetarians, it is also a common alternative to meat because of its high protein cotent. However, a considerable number of people, particularly children, show allergic reactions such as skin rashes, gastrointestinal problems, or in more serious cases, swelling and diffulty of breathing and swallowing. If not for this, soy would have been an ideal food item, considering its nutritional value and relatively cheap price.

This is why scientists have tried to create genetically modified soybeans that are non-allergenic. They simply shut off that gene called p34, which has been found to be responsible for producing the protein that invokes allergic reactions. However, because of public resistance to GMOs, they tried other traditional approaches as well.

Alas, researchers from the University of Illinois and the USDA-Agricultural Research Service have been rewarded. After screening more than 16,000 soybean lines in the USDA's National Soybean Germplasm Collection, they found two varieties that are naturally deficient in the allergy-causing P34 protein. They said they will release these soybean varieties without patents to companies and breeders. Hopefully it doesn't take long before we consumers see them on the store shelves!........

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May 6, 2006, 5:49 PM CT

No-Mow Grass May Be Coming Soon

For anyone tethered to a lawnmower, the Holy Grail of horticultural accomplishment would be grass that never grows but is always green.

Now, that vision of suburban bliss-and more-seems plausible as researchers have mapped a critical hormone signaling pathway that regulates the stature of plants. In addition to lawns that rarely require mowing, the finding could also enable the development of sturdier, more fruitful crop plants such as rice, wheat, soybeans, and corn.

In a paper reported in the May 4, 2006, issue of the journal Nature, Howard Hughes Medical Institute researchers report they have deciphered the signaling pathway for a key class of steroid hormones that regulates growth and development in plants.

"By manipulating the steroid pathway.....we think we can regulate plant stature and yield," said Joanne Chory, a Howard Hughes Medical Institute investigator at the Salk Institute for Biological Studies, and the senior author of the new report.

Manipulation of plant stature has been a longstanding goal in horticulture, agronomy, and forestry. The ability to precisely control plant size would have broad implications for everything from urban forestry to crop and garden plant development. Beyond perpetually short grass, trees could be made more compact for better growth in crowded cities, and berry bushes could be made taller for ease of harvesting.........

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May 3, 2006, 10:08 PM CT

Root-development Pathway Mapped

Biologists have vastly expanded understanding of the biological machinery controlling the intricate process by which plant roots burgeon from single cells into complex tissues. A Duke-led team's discovery of new components of the root-development pathway in the mustard plant, Arabidopsis thaliana, represents both a scientific and technical achievement, the researchers said.

Scientifically, Arabidopsis is a basic biological model for all flowering plants, so the finding offers insights into a critical function of all such plants, including crop plants, the scientists said. Further, since the root is a useful model for tissue development in general, basic findings regarding the root-development pathway could offer insights into how complex tissues are generated from immature cells, called stem cells.

Technically, the genomic analytical method they used also will offer biologists a highly useful approach to discovering the components of complex biological pathways governing development, the scientists said. Their statistical "meta-analysis" technique involved using computational methods to integrate data from multiple genetic analyses using several DNA microarrays -- popularly known as "gene chips." Each of these chips contained some 24,000 genes representing nearly the entire genome of the Arabidopsis plant.........

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May 1, 2006, 11:43 PM CT

Biotech Cotton Provides Same Yield

Arizona farmers receive the same yield/acre, use fewer chemical insecticides and maintain insect biodiversity when they plant the biotech cotton known as Bt cotton, as per new research.

The finding comes from the first large-scale study that simultaneously examined how growing Bt cotton affects yield, pesticide use and biodiversity.

It's good news for the environment.

"What we see is that it's positive here in Arizona -- no doubt about it," said Yves Carrière, an associate professor of entomology at The University of Arizona in Tucson. "We've reduced pesticide use in Arizona. We've wanted to do that for 25 years".

Bt cotton has been genetically altered to produce Bt toxin, a naturally occurring insecticide that kills pink bollworm, a major pest of cotton. Bt cotton has been planted in Arizona since 1996. Now more than half of the state's 256,000 acres of cotton fields are planted with the biotech plants.

Some have suggested that, in addition to killing the target pests, insecticide-containing crops like Bt cotton would also kill beneficial and non-target arthropods.

The new study found that Bt cotton, also known as transgenic cotton, does not affect the biodiversity of insects in cotton fields.

Carrière said, "There were lots of factors that affected biodiversity in this study. Transgenics were not one of them."........

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May 1, 2006, 0:13 AM CT

botanist and the vintner - Book Review

A phids have never enjoyed a especially good press. Their huddled masses rain excrement on our parked cars and bring disease and destruction to the crops and gardens of almost all temperate regions. But in the aphid rogues' gallery, one species has pride of place, the arch villain of them all-the grape phylloxera, which practically destroyed the French wine industry in the 19th century. Christy Campbell's book tells the epic story of how this insect was eventually defeated. It is a tale worth telling because this was an immensely important episode in ecological history, indeed a classic of invasion biology, with lessons that resonate for us today as we face mounting threats from the ravages of non-native species.

The bare bones of the story will be familiar to most wine drinkers. Phylloxera was introduced into a French vineyard in the Rhone Valley on the roots of living American vines in the 1860s. French vines, in contrast to most American vines, were very susceptible to the insect, which had evolved with the native American vine species and did not cause them appreciable damage. Phylloxera spread slowly but inexorably across the wine-growing regions of France, reaching the Champagne in 1890, and it eventually conquered all the major wine-growing regions of the world, with the exception of Chile. America provided the cure as well as the cause. American vines, the insects' Trojan horse, were not harmed by the insect, and could be used as rootstocks on which the susceptible European vine species Vitis vinifera could be grafted. This method was amazingly successful and continues to be used to keep the insect at bay. In hindsight the solution may seem obvious, but this book makes clear what an immense struggle was involved. Indeed, Campbell's book illustrates what a difficult, messy, and unpredictable business science can be, and what sheer hard work it is to translate scientific results into action.........

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