January 7, 2009, 11:31 PM CT

Herbicide Use Can Damage Potato Reproduction

Currently, plant testing in the United States to determine potential ecological risks from chemical pesticides to nontarget plants requires two tests, both of which use immature plants. Protection of the plant development and reproduction are not considered, unlike tests mandatory for the protection of animals. Past research conducted by the USEPA and others have shown that plant development/reproduction is not adequately protected with the current test protocols.

The stage of plant development when exposed to a pesticide has an important impact on what plant organs are injured. Vegetation may or may not display symptoms of injury when reproductive organs are severely damaged. Yield and quality reduction can have significant economic and ecological effects. Therefore, field trials were conducted to determine if potato vegetative growth and tuber yield and quality were affected by herbicides at below recommended field rates.

Potato plants were exposed to one of seven different herbicides at various concentrations below normal field application rates. Results from this study were reported in the November-recent issue of the Journal of Environmental Quality. They demonstrated that potato tuber yield and quality can be affected by herbicide application rates below those causing a reduction in vegetative growth or injury. Potato tuber formation appears to be a sensitive indicator of developmental/reproductive responses of plants to chemical pesticides......... Posted by: Erica      Read more         Source

January 6, 2009, 7:37 PM CT

About harmful algal blooms

Cambridge, Md. An international group of researchers is linking nutrient pollution in the world's coastal seas to an increase in the number of harmful algal blooms reported in recent years. When harmful algal blooms (HAB's) occur, they taint seafood with toxins, cause human respiratory and skin irritations and cause fish or mammal kills in coastal waters.

In the December edition of the journal Harmful Algae, researchers present a compilation of 21 articles outlining the role of nutrient pollution in the increasing frequency of these events.

"Harmful algal blooms can have direct effects on human health and the environmental balance of our coastal waters," said journal editor and University of Maryland Center for Environmental Science researcher Dr. Patricia Glibert. "By tapping the expertise of a number of of the world's leading voices on harmful algal blooms, this series of papers hopes to elevate this issue to the forefront of coastal management issues needing immediate attention".

The journal outlines several key issues driving the expansion of HAB's in the United States and the world.

• Degraded water quality from increased nutrient pollution promotes the development and persistence of a number of HABs;
• Understanding the complex relationships between nutrients and the outbreak of harmful algae is key to reducing future blooms; and,
.........


Posted by: Erica      Read more         Source

January 6, 2009, 7:27 PM CT

Plant polymerases IV and V

A team of biologists at Washington University in St. Louis has discovered that two vital cellular components, nuclear RNA Polymerases IV and V (Pol IV and V), found only in plants, are actually specialized forms of RNA Polymerase II, an essential enzyme of all eukaryotic organisms, including humans.

"We've caught evolution in the act," said Craig Pikaard, Ph.D., WUSTL professor of biology in Arts & Sciences. "We've known for decades that RNA Polymerases I, II and III are found in all eukaryotes, but it's only over the past several years that we've been aware that plants have two more nuclear polymerases, Pol IV and Pol V. Now it is clear that these enzymes evolved from Pol II over the past several hundred-million years. This is a new snapshot into the evolution of RNA polymerases, which are the enzymes responsible for decoding the information stored in the chromosomes."

Analyzing purified Pol IV and Pol V by a sophisticated technique known as tandem mass spectrometry, the Pikaard lab and a team of collaborators at Pacific Northwest National Laboratory, led by Ljiljana Paa-Toli, discovered 12 subunits in both Pol IV and Pol V that correspond one-for-one to the 12 subunits of Pol II. Some of the Pol IV and Pol V subunits are encoded by the same genes as the corresponding Pol II subunits, but others come from duplicated Pol II subunit genes that have changed over time. Overall, four subunits of Pol IV are distinct from their Pol II counterparts, six subunits of Pol IV are different from their Pol II counterparts, and four subunits differ between Pol IV and Pol V. Yet, all of the Pol IV and Pol V subunits are "apples that haven't fallen far from the Pol II tree."........ Posted by: Erica      Read more         Source

January 5, 2009, 11:39 PM CT

Shade trees reduce electricity use

A recent study shows that shade trees on the west and south sides of a house in California can reduce a homeowner's summertime electric bill by about $25.00 a year. The study, conducted last year on 460 single-family homes in Sacramento, is the first large-scale study to use utility billing data to show that trees can reduce energy consumption.

"Everyone knows that shade trees cool a house. No one is going to get a Nobel Prize for that conclusion," says the co-author of study, Geoffrey Donovan. "But this study gets at the details: Where should a tree be placed to get the most benefits? And how exactly do shade trees impact our carbon footprint?".

Donovan, a research forester with the Forest Service's Pacific Northwest (PNW) Research Station, is a co-author of the report with economist David Butry of the National Institutes of Standards and Technology. The report, "The Value of Shade: Estimating the Effect of Urban Trees on Summertime Electricity Use," has been submitted for publication to the journal Energy and Buildings

The scientists chose to do their study on homes in Sacramento because of the city's hot summers and the fact that most people use air conditioners. The Sacramento Municipal Utility District operates an active tree planting program and residents are eligible for up to 10 free trees annually through a program delivered in partnership with the Sacramento Tree Foundation......... Posted by: Erica      Read more         Source

December 22, 2008, 9:29 PM CT

Modified plants may yield more biofuel

"There is lots of energy-rich cellulose locked away in wood," said John Carlson, professor of molecular genetics, Penn State. "But separating this energy from the wood to make ethanol is a costly process requiring high amounts of heat and caustic chemicals. Moreover, fungal enzymes that attack lignin are still not widely available, still in the development stage, and not very efficient in breaking up lignin."

Scientists have previously tried to get around the problem by genetically decreasing the lignin content in plants. However, this can lead to a variety of problems -- limp plants unable to stay upright, and plants more susceptible to pests.

"Trying to engineer trees without lignin is like trying to engineer boneless chicken," said Ming Tien, professor of biochemistry, Penn State. "It just doesn't make sense".

Carlson, Tien and postdoctoral associate Haiying Liang use a different genetic approach. Instead of decreasing the lignin content, they are trying to modify the connections in lignin, without compromising either the biosynthesis of lignin or the structural rigidity of the plant.

The Penn State geneticists and biochemists took a gene from beans and engineered it into a poplar tree. This gene produces a protein that inserts itself between two lignin molecules when the lignin polymer is created......... Posted by: Erica      Read more         Source

December 9, 2008, 10:31 PM CT

Secret Ingredient For The Health of Tropical Rainforests

A team of scientists led by Princeton University researchers has found for the first time that tropical rainforests, a vital part of the Earth's ecosystem, rely on the rare trace element molybdenum to capture the nitrogen fertilizer needed to support their wildly productive growth. Most of the nitrogen that supports the rapid, lush growth of rainforests comes from tiny bacteria that can turn nitrogen in the air into fertilizer in the soil.

Until now, researchers had thought that phosphorus was the key element supporting the prodigious expansion of rainforests, as per Lars Hedin, a professor of ecology and evolutionary biology at Princeton University who led the research. But an experiment testing the effects of various elements on test plots in lowland rainforests on the Gigante Peninsula in the Barro Colorado Nature Monument in Panama showed that areas treated with molybdenum withdrew more nitrogen from the atmosphere than other elements.

"We were surprised," said Hedin, who is also a professor in the Princeton Environmental Institute. "It's not what we were expecting".

The report, detailed in the Dec. 7 online edition of Nature Geoscience, will be the journal's cover story in its print edition.

Molybdenum, the team found, is essential for controlling the biological conversion of nitrogen in the atmosphere into natural soil nitrogen fertilizer, which in turn spurs plant growth. "Just like trace amounts of vitamins are essential for human health, this exceedingly rare trace metal is indispensable for the vital function of tropical rainforests in the larger Earth system," Hedin said. Molybdenum is 10,000 times less abundant than phosphorus and other major nutrients in these ecosystems......... Posted by: Erica      Read more         Source

December 9, 2008, 9:15 PM CT

Application quantifies carbon sequestration of urban trees

U.S. Forest Service researchers at the Center for Urban Forest Research are providing online software that can show users how much carbon dioxide an urban tree in California has sequestered in its lifetime and the past year.

The Tree Carbon Calculator is free and programmed in a Microsoft Excel spreadsheet that provides carbon-related information for a single tree in one of six California climate zones. It is the only tool approved by the California Climate Action Registry's Urban Forest Project Reporting Protocol for quantifying carbon dioxide sequestration from tree planting projects.

It can be found at the U.S. Forest Service Climate Change Resource Center Web site, http://www.fs.fed.us/ccrc/topics/urban-forests/.

In addition, the tool is available on the Center for Urban Forest Research Web site, http://www.fs.fed.us/psw/programs/cufr/.

Users enter information such as a tree's climate zone, species name, size or age. The program then estimates how much carbon dioxide the tree has sequestered in the past year and its lifetime. It also calculates the dry weight of the biomass that would be obtained if it were removed.

Trees planted near buildings to cut heating and cooling costs require additional inputs because they also reduce the greenhouse gases power plants emit while generating electricity. The Tree Carbon Calculator automatically calculates power plant reductions using emission factors for local utilities......... Posted by: Erica      Read more         Source

November 24, 2008, 10:06 PM CT

Nutrients in water may be a bonus for agriculture

Agriculture producers may find they don't have to bottle their water from the Seymour Aquifer in the Rolling Plains to make it more valuable, as per Texas AgriLife Research scientists.

Drs. John Sij, Cristine Morgan and Paul DeLaune have studied nitrate levels in irrigation water from the Seymour Aquifer for the past three years, and have found nitrates can be as high as 40 parts per million. Though unacceptable for drinking, the water would benefit agricultural producers who use it for irrigation.

This high concentration of nitrates is a concern because it exceeds the federal safe drinking water standards as the aquifer is used as a municipal water source for the communities of Vernon, Burkburnett and Electra, as well as some rural families, Sij said.

"When you get more than 10 parts per million, it exceeds the federal limit," he said. "Our water at Chillicothe is around 20 parts per million, so we don't give it to the babies, but adults can drink it."

Nitrate levels range from 3 parts per million to 40 parts per million in the aquifer, so the situation is being addressed by the Texas State Soil and Water Conservation Board, with grant funding from the Environmental Protection Agency.

Also working on the project are the Haskell, Wichita-Brazos and California Creek Soil and Water Conservation districts, the U.S. Department of Agriculture-Natural Resources Conservation Service, Texas AgriLife Extension Service, Texas A&M AgriLife's Texas Water Resources Institute, Rolling Plains Groundwater Conservation District and AgriLife Research......... Posted by: Erica      Read more         Source

Sun, 23 Nov 2008 22:32:23 GMT

Alonsoa unilabiata

Thanks again to Jackie Chambers for today''s entry (both the photograph and write-up):

There is something mysteriously attractive about Alonsoa unilabiata, or the mask flower. The pink flowers have a dark purple centre with two obvious yellow patches -- giving the slightly eerie effect of bright eyes looking out from behind a mask. The dark centre to the flower and contrasting yellow patches are characteristics shared by members of the closely-related genus Diascia, e.g., Diascia longicornis.

The rather theatrical effect created by the petals is complimented by the double rows of curved appendages at the base of the flower. These are the stamens, which are swollen and curled downwards, also seen in this photograph.

These peculiar flowers range from 15-18 mm across, and bloom from August to October. This annual plant can reach up to 15cm in height and has oval leaves with toothed margins arranged in opposite pairs along the stem.

This little flower was spotted at Vanrhyn''s Pass, just outside of the small village of Nieuwoudtville on the Bokkeveld Plateau, an area which is home to an incredible variety of spring-flowering annuals and geophytes. For more about this fascinating place (and to start planning your own trip) see Nieuwoudtville -- Place of Hidden Treasures. Posted by: Daniel Mosquin      Read more     Source

November 14, 2008, 8:51 PM CT

Formula for longer plant life

Plants that grow more slowly stay fresh longer. In their study now published in PLoS Biology, researchers at the Max Planck Institute for Developmental Biology in Tübingen have shown that certain small sections of genes, so-called microRNAs, coordinate growth and aging processes in plants. These microRNAs inhibit certain regulators, known as TCP transcription factors. These transcription factors in turn influence the production of jasmonic acid, a plant hormone. The higher the number of microRNAs present, the lower the number of transcription factors that are active, and the smaller the amount of jasmonic acid, which is produced by the plant. The plant therefore ages more slowly, as this hormone is important for the plant's aging processes. The scientists have succeeded for the first time in describing the antagonistic regulation of growth and aging in plants. Since the quantity of microRNAs in the plants can be controlled by genetic methods, it may be possible in future to cultivate plants that live longer and grow faster. (PLoS Biology, September 23, 2008).

MicroRNAs are short, single-strand sections of genes that regulate other genes. They do this by binding to complementary sections of the genetic material, thus preventing them from being read and implemented in genetic products. In plants, microRNAs mainly inhibit other regulators, so-called transcription factors. These factors can switch genes on or off by binding to DNA sections, thus activating or blocking them so that either too a number of or too few proteins are formed. Since proteins control metabolic processes, an imbalance leads to more or less clearly visible changes to the plant......... Posted by: Erica      Read more         Source