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Fungi May Benefit Science
Australian relatives of these American cicadas play host to fungi recently found to produce potent antimicrobial compounds.
Plant physiologist Donna Gibson of ARS' Plant Protection Research Unit (PPRU) and Cornell research associate Stuart Krasnoff found peptides within C. heteropoda that give it antimicrobial and immunosuppressant properties. They also found that the fungus produces myriocin, a compound being investigated by other researchers for potent immunosuppressant activity that could be a key to preventing post-transplant organ rejection in humans. The peptides are made up of unusual amino acids, one of which causes the peptide to coil into a helical structure, as per Gibson. This, she added, may be useful for engineering molecules, because most drugs and pesticides are modeled after the chemical structures of natural products. Most Americans likely base their recollection of cicadas on their experience with Brood X of Magicicada septendecimthe. That's the species that emerges every 17 years, mostly in eastern parts of the nation, to pile atop one another on sidewalks, bump into windows and people, and collect in storm gutters as they emerge for their mating cycle......... Posted by: Jessica Permalink Pest-Removing For Cherry Packing
Fresh Bing cherries.
Photo by Peggy Greb.
As per ARS entomologist Jim Hansen, such pests pose more of a consumer-marketing problem than a field-production one, since they can occur on sweet cherries that have been packed for domestic sale or export. In addition to culling and sorting measures, Hansen is experimenting with dips, baths and sprays containing polydimethyl silicone emulsions and other food-grade surfactants, which, in effect, wash the pests off the cherries' surface. Surfactants are typically used as wetting or dispersing agents in products ranging from soaps and shampoos to paints and insecticides. But recent studies by Hansen and others have shown that some silicone-based surfactants will remove spider mites, thrips and mealy bugs from apples and pears. Hansen's surfactant studies at ARS' Fruit and Vegetable Insect Research Unit in Wapato kicked into high gear in 2005 when ARS entered into a research agreement with the California Cherry Advisory Board (CCAB). The collaboration makes sense since Washington and California are the nation's top two sweet cherry producers, exporting more than half their fresh-market harvests......... Posted by: Jessica Permalink First Amazon-Andean crop plant transfer
Amazon River
Heading to the supermarket to pick up some corn flour, a couple of tomatoes or a can of beans commonly doesn't conjure up the notion of 10,000 years of agricultural development in the Americas--a transition from hunter-gatherer cultures to agricultural cultures actively developing and trading new food crops. But this transition is still inadequately understood. New excavations and a growing collection of plant microfossil remains rapidly adds pieces to this puzzle. A multidisciplinary team excavated a stone house at Waynuna, north of Arequipa on the western slope of the Andes and analyzed plant remains from three grinding stones. Arrowroot from the Amazon. Starchy arrowroot (Maranta sp.) tubers don't grow in the Andean highlands. So the presence of tiny Arrowroot starch grains and phytoliths on the grinding stones and in associated sediments means that people were moving tubers from lowland Amazon rainforest sites east of the Andes west to the Waynuna site......... Posted by: Jessica Permalink Watermelon Line May Combat Mildew
Recently, two races of powdery mildew have been reported on watermelon, and they appear to be geographically separate. Existing watermelon lines, which were thought resistant, were found to be susceptible. But ARS scientists and his colleagues discovered the first documented resistance to race 1 powdery mildew in an ARS germplasm collection. The researchers first analyzed existing lines from the ARS Southern Regional Plant Introduction Station in Griffin, Ga., for resistance to race 1 using field and growth chamber studies. They developed the new watermelon line, PI 525088-PMR, by repeatedly selecting the most resistant plants from the line PI 525088 (Citrullus lanatus var. lanatus). As per Angela R. Davis, geneticist at the ARS South Central Agricultural Research Laboratory in Lane, Okla., watermelon has historically been resistant to powdery mildew, but the disease has become widespread during the past few years. A significant problem in Europe and Africa for about a decade, powdery mildew has emerged as a severe problem in some areas of the United States......... Posted by: Jessica Permalink Source February 2, 2006, 8:24 PM CT Diseases Resistant Sugar Canes
ARS researchers Barry Glaz, Jimmy D. Miller, Peter Y.P. Tai and Jack C. Comstock at the agency's Sugarcane Field Station in Canal Point, Fla., collaborated with James M. Shine Jr. of the Florida Sugar Cane League and Christopher W. Deren, formerly with the University of Florida, to develop the new variety. ARS is the U.S. Department of Agriculture's chief in-house scientific research agency. As the nation's largest producer of sugarcane and sugar, Florida fills more than 22 percent of the nation's domestic sugar needs. The sugar industry in Florida processes 2 million tons of raw and refined sugar each year, adding more than $2 billion to the state's economy. At the heart of the Florida sugar industry is Lake Okeechobee, in the area where approximately 450,000 acres of sugar cane are grown annually. Proximity to the lake is important, because it offers cold moderation to the tender cane during occasional harsh winter weather......... Posted by: Jessica Permalink February 2, 2006, 8:18 PM CT A Heartier Apple Tree
This material shows potential for helping breed trees that bear popular, domestic apples while standing up to destructive diseases and fungi, as per Agricultural Research Service (ARS) scientists. The genetic material was gathered during U.S. Department of Agriculture (USDA) sponsored excursions to Asia and Europe aimed at expanding the known genetic diversity of apples. Horticulturist Phil Forsline and plant geneticist Gennaro Fazio of ARS' Plant Genetics Research Unit have used the material to raise orchards of the exotic apples near their laboratory in Geneva, N.Y. And, with colleagues in ARS and Cornell University, they've documented with astonishment the disease resistance of a number of of these trees and the domestic species they've bred with them. Forsline went on seven of the collecting trips, including four to central Asia. The trips resulted in at least a doubling of the known genetic diversity of apple trees, as per Forsline. The researchers returned with 949 apple tree accessions from central Asia alone. Other excursions were to China, the Caucasus region including Russia and Turkey, and Gera number of. Fazio and Forsline are most impressed with the material collected in Kazakhstan, particularly accessions of Malus sieversii, an important forerunner of the domestic apple. This is logical, given that Kazakhstan is a likely ancestral origin of familiar domestic apples (Malus x domestica) such as Red Delicious, Golden Delicious and McIntosh......... Posted by: Jessica Permalink January 28, 2006, 8:35 PM CT Plants Size And Metabolism
In a report published in the Jan. 26 issue of the journal Nature, biologist Peter Reich of the University of Minnesota and his colleagues found that the rate of plant metabolism, or respiration--and its related emissions of carbon dioxide--can be deduced from the nitrogen content of any plant. Plants carry out respiration during the dark hours when they, like animals, take in oxygen and give off carbon dioxide. During daylight, plants carry out photosynthesis, in which the process is reversed. Researchers have estimated that plant respiration releases five to 10 times as much carbon dioxide as fossil fuel burning. It's crucial, they say, to know the amount of plant emissions more accurately. Yet, "the amount of carbon dioxide given off by plants is one of the weak spots in models of global carbon cycling," Reich said. The research was conducted at the National Science Foundation (NSF)'s Cedar Creek Long-Term Ecological Research (LTER) site in Minnesota, one of 26 such NSF LTER sites......... Posted by: Jessica Permalink January 23, 2006, 9:21 PM CT citrus greening can be managed
"In the long term, the industry can live with and manage the canker problem, but citrus greening is a fatal disease that's an even larger threat to the state's signature crop," said Harold Browning, director of the University of Florida's Citrus Research and Education Center in Lake Alfred. "In other areas of the world where greening is a problem, it has never been successfully eradicated". The disease, which slowly weakens and kills all types of citrus trees, causes fruit to become lopsided and taste bitter, making it unusable. Fruit does not develop the desired color, hence the greening name. There is no known cure for the disease, which is on the U.S. Department of Agriculture's select list of threats to plants and wildlife regulated by the Agricultural Bioterrorism Protection Act. Greening does not harm people. Browning said the fatal bacterial disease is transmitted by the Asian citrus psyllid (Diaphorina citri), a tiny insect that is now widely distributed throughout Florida, and the disease has been found in more than 440 locations in 11 counties. Browning said it's not practical to eradicate citrus greening, but the spread of the disease can be slowed with an effective integrated pest management program (IPM) that includes limited use of systemic insecticides and beneficial insects that attack the psyllid......... Posted by: Erica Permalink January 20, 2006, 6:23 AM CT Increased Competition For Pollen
Credit: Bree Belyea, UCSB
The analysis shows that ecosystems with the largest number of different species, including the jungles of South America and Southeast Asia and the rich shrubland of South Africa, have bigger deficits in pollination compared to the less-diverse ecosystems of North America, Europe and Australia. "The global pattern we observed suggests that plants in species-rich regions exhibit a greater reduction in fruit production due to insufficient pollination than plant species in regions of lower biodiversity," said Susan Mazer, a co-author of the article and a biologist at the University of California, Santa Barbara. Typically she and her colleagues believe such biodiversity "hotspots" are characterized by stronger competition among plant species for pollinators, such that a number of plant species simply don't receive enough pollen to achieve maximum fruit and seed production. "A number of plants rely on insects and other pollen vectors to reproduce," said Jana Vamosi, an evolutionary biologist at the University of Calgary and co-author of the paper. "We've found that in areas where there is a lot of competition between individuals and between species, a number of plants aren't getting enough pollen to successfully reproduce. If plants can't survive, neither can animals. These biodiversity hotspots are important because they are where we most often find new sources of drugs and other important substances. They are also the areas where habitat is being destroyed the fastest"......... Posted by: Jessica Permalink January 18, 2006, 8:38 PM CT More Carbon From High Arctic Soil
Ronald Sletten begins excavating a pit at a spot near Thule Air Base in Greenland as Jennifer Horwath examines the soil.
A three-year study of soils in northwest Greenland found that a key prior study greatly underestimated the organic carbon stored in the soil. That's because the earlier work generally looked only at the top 10 inches of soil, said Jennifer Horwath, a UW doctoral student in Earth and space sciences. The earlier work, reported in 1992, estimated nearly 1 billion metric tons of organic carbon was contained in the soil of the polar semidesert, a 623,000-square-mile treeless Arctic region that is 20 percent to 80 percent covered by grasses, shrubs and other small plants. That research also estimated about 17 million metric tons of carbon was sequestered in the soil of the adjacent polar desert, a 525,000-square-mile area where only 10 percent or less of the landscape is plant covered. Horwath dug substantially deeper, in some instances more than 3 feet down, and found significantly more carbon. She concluded that the polar semidesert contains more than 8.7 billion metric tons of carbon, and the polar desert contains more than 2.1 billion metric tons......... Posted by: Tyler Permalink |
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