October 11, 2010, 7:57 AM CT

Plants kick-start evolutionary drama

An international team of scientists, exploiting pioneering techniques at Arizona State University, has taken a significant step toward unlocking the secrets of oxygenation of the Earth's oceans and atmosphere.

Evolution of the Earth's multitude of organisms is intimately associated with the rise of oxygen in the oceans and atmosphere. The new research indicates that the appearance of large predatory fish as well as vascular plants approximately 400 million years ago coincided with an increase in oxygen, to levels comparable to those we experience today. If so, then animals from before that time appeared and evolved under markedly lower oxygen conditions than previously thought.

The researchers, including collaborators from Harvard, Denmark, Sweden and the United Kingdom, made use of a method developed at ASU by Ariel Anbar, a professor in the department of chemistry and biochemistry and the School of Earth and Space Exploration in the College of Liberal Arts and Sciences, and his research group. The method can be used to estimate global oxygen levels in ancient oceans from the chemical composition of ancient seafloor sediments.

Their important findings are presented in a paper published in this week's online Early Edition of the Proceedings of the National Academy of Sciences (PNAS), titled "Devonian rise in atmospheric oxygen corcorrelation to radiations of terrestrial plants and large predatory fish"......... Posted by: Kelly      Read more         Source

September 29, 2010, 11:10 PM CT

Species Accumulate on Earth at Slower Rates

Computational biologists at the University of Pennsylvania say that species are still accumulating on Earth but at a slower rate than in the past.

In the study, reported in the journal PLoS Biology, Penn scientists developed a novel computational approach to infer the dynamics of species diversification using the family trees of present-day species. Using nine patterns of diversification as alternative models, they examined 289 phylogenies, or evolutionary trees, representing amphibians, arthropods, birds, mammals, mollusks and flowering plants.

The study demonstrated that diversity is generally not at equilibrium. Nonetheless, speciation rates have typically decayed over time, suggesting that the diversification of species is somehow constrained, and that equilibrium may eventually be reached.

There are a number of competing theories for how species diversify and become extinct. Some suggest that species continually accumulate in time, always finding new ecological niches. Other theories suggest that the number of coexisting species is limited and that we will eventually have equilibrium. In other words, a species will be born only when another goes extinct.

The question that intrigued the Penn scientists was whether species diversity on Earth is in equilibrium or is still expanding. They also wondered whether the world has an invisible stop sign on species diversity that would eventually limit the diversity on the planet......... Posted by: Erica      Read more         Source

September 25, 2010, 9:33 AM CT

Analysis of the Chocolate Genome

The sequencing and analysis of the genome for the Criollo variety of the cacao tree, generally considered to produce the world's finest chocolate, was completed by an international team led by Claire Lanaud of CIRAD in France, with Mark Guiltinan of Penn State University, along with researchers from 18 other institutions. "The large amount of information generated by this project dramatically changes the status of this tropical plant and its potential interest for the scientific community," said Guiltinan, professor of plant molecular biology.

The scientists not only sequenced the genome of this ancient plant, but assembled 76 percent of the genome linking 82 percent of those genes to the 10 cacao chromosomes. This analysis identified a variety of gene families that may have future impact on improving cacao trees and fruit either by enhancing their attributes or providing protection from fungal diseases and insects that effect cacao trees.

"Relics of the ancestral Criollo first cultivated by Olmec or Maya people can still be encountered in old Mesoamerican plantations or in forests where the Maya live," said Siela Maximova, associate professor of horticulture and a member of the research team. "Our genome sequence is derived form a Belizean Criollo plant collected in the Mayan mountains"......... Posted by: Erica      Read more         Source

September 25, 2010, 8:28 AM CT

Withering well can improve fertility

Contrary to a thousand face cream adverts, the secret of fertility might not be eternal youth. Research by the ecologist Dr. Carlos Herrera, a Professor of Research at the Consejo Superior de Investigaciones Cientficas in Seville, Spain has shown that the withering action of flowers may have evolved to protect their seeds. His research is reported in the October 2010 issue of the Annals of Botany (http://dx.doi.org/10.1093/aob/mcq160).

Prof. Herrera said: "No one has paid much attention to the corollas, collections of petals on a flower, when they shrivel. Their job is done, so it's no surprise they die. But if their job is done, why don't the petals simply drop off the plant? I thought there might be an advantage that kept the old corollas on the plant".

To test his idea, Herrera conducted a very simple experiment. He removed dead petals from some lavender. Then he observed what happened to the seeds.

Prof. Herrera said: "The results for the lavender were striking. Normally you'd expect around 60% of the lavender fruits to ripen. Without the withered petals around the fruit, only 40% ripened. The dead petals seem to have formed a protective barrier around the fruit. In this case the barrier helps prevent attack by gnat larvae who like to feed on lavender seeds"......... Posted by: Erica      Read more         Source

September 25, 2010, 7:55 AM CT

First Cultivated Ohelo Berry for Hawaii

The first cultivar of 'Ōhelo berry, a popular native Hawaiian fruit, has been released by U.S. Department of Agriculture (USDA) researchers and their university and industry cooperators.

'Ōhelo (Vaccinium reticulatum Smith) is a small, native Hawaiian shrub in the cranberry family, usually found at high elevations on the islands of Maui and Hawaii. As people scour the landscape to harvest this delectable berry for use in jam, jelly and pie filling, they unfortunately disrupt the fragile habitats where this plant grows.

In an effort to reduce damage to the environment and meet consumer demands, horticulturist Francis T.P. Zee, with the USDA Agricultural Research Service (ARS) Pacific Basin Agricultural Research Center (PBARC) in Hilo, Hawaii, is evaluating 'Ōhelo for small farm production and ornamental use. Zee collaborated with fellow ARS researchers and cooperators at the University of Hawaii at Manoa, Big Island Candies and the Big Island Association of Nurserymen. ARS is the principal intramural scientific research agency of USDA.

Zee and his team selected the offspring of seed-grown plants to create the new cultivar "Kilauea" for berry production. They found 'Ōhelo's tiny seeds readily germinated under 20-30 percent shade in well-watered and well-drained potting mixture. Plant hardiness and vigor improved with age, and some seedlings flowered just 10 months after germination, much sooner than the 5 years reported in prior studies. The 16-month-old plants Zee successfully transplanted from the greenhouse to the field produced berries a year later......... Posted by: Erica      Read more         Source

September 9, 2010, 6:52 AM CT

First discovery of bilirubin in a flower

A research team led by Cary Pirone from the Department of Biological Sciences at Florida International University has identified bilirubin in the popular Bird of Paradise plant. The breakthrough study, reported in the September 2010 issue of the American Society for Horticultural Science's journal HortScience, provides new insights into color production in this iconic tropical plant.

Previously believed to be an "animal-only" pigment, bilirubin is best known as the yellowish hue linked to bruises and jaundice sufferers. In 2009 the FIU scientists found bilirubin in the arils of Strelitzia nicolai, the white Bird of Paradise tree. The incredible discoverythat bilirubin exists in both plants and animalsput Pirone's research on the scientific map. The current study expands the original research and reveals new insights into the presence of animal pigment in flowers. Advisor David Lee credits Pirone for her persistence and scientific acumen. "Cary has made a remarkable discovery", he noted, adding that it was Pirone's persistence and curiosity that persuaded colleagues that she was on the right track.

Strelitzia reginae Aiton, the Bird of Paradise plant, is known for its vibrant orange and blue inflorescences. Native to South Africa, it is widely cultivated in warm temperate and tropical regions. Aside from the widely recognized shape of its flower, which resembles the head of a bird, Strelitzia reginae is also admired for its brilliant floral coloration. In contrast to its showy flowers, the fruit of the Bird of Paradise is pale and partially obscured by the bract during development. When it matures, however, the capsule breaks open to reveal intensely colored orange arillate seeds. Remarkably, the distinct aril color can remain unchanged for decades after the plant dies......... Posted by: Erica      Read more         Source

September 8, 2010, 7:21 AM CT

Plant Nutrients from Wastewater

Nitrogen, phosphorous and potassium - there are valuable nutrients contained in wastewater. Unfortunately, these essential nutrients are lost in conventional wastewater therapy plants. This is the reason why scientists at Fraunhofer have been working on processes for regaining these nutrients in the form that can be used for agriculture. They are showcasing their work at Fraunhofer's stand at the IFAT ENTSORGA fair (September 13-17 in Munich, Gera number of).

Plants cannot thrive without nutrients such as nitrogen, phosphorous or potassium, therefore farmers commonly use organic and industrially manufactured mineral fertilizers to supply wheat, maize and others with these vital substances. In future, the need for nutrients will be soaring because we will only be able to supply the world's growing population with food and cover surging demands for biofuels by using fertilizers. Logically, that causes the prices for these nutrients to skyrocket. But that is not the only problem. The deposits of rock phosphates mandatory for manufacturing phosphate fertilizers are becoming increasingly scarce. The scientists at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB in Stuttgart, Gera number of are working at alternatives. They want to recover these essential nutrients from wastewater......... Posted by: Erica      Read more         Source

Sat, 28 Aug 2010 05:08:13 GMT

Eomecon chionantha

Another round of thanks to J.G. in S.F.@Flickr for contributing an image to BPotD (original image | Botany Photo of the Day Flickr Pool). This continues the series on the plant biodiversity of China.

Eomecon chionantha is known in English as either dawn-poppy or snow-poppy. The species is widespread in eastern temperate China, where plants grow in woodlands with moist soils and dappled shade.

Christopher Grey-Wilson, in his 1993 book Poppies, extols the virtues of Eomecon chionantha as a garden plant. In addition to the "simplicity of its elegant white flowers", he mentions that the leaves retain interest for much of the growing season. For a photograph of an entire plant, scroll down this page on perennials growing at the Botanic Gardens and Arboretum of Mendel University of Agriculture and Forestry, in Brno, Czech Republic. You can also read about an Ontarian gardener"s experience with Eomecon chionantha at Teza"s Garden. Grey-Wilson concludes his account of Eomecon chionantha with "Amongst the gaudier and more brazen races of poppy this ones makes a pleasant and subtler contrast and for that reason it is often dismissed as a "planter"s plant". This is generally taken to mean that none but the most dedicated gardener would dream of growing it, or, indeed would want to but this surely would be wholly unjustified."

The underground components of Eomecon chionantha have a couple interesting properties. First, the lengthy underground stolons "ooze an orange-red sap when cut", according to Grey-Wilson. Secondly, an extract from the rhizome (or root-stalk) has been investigated as an economic source of a molluscicide by Chinese scientists. Gardeners will be familiar with molluscicides, such as snail or slug bait, for control of these sometimes pests. The impetus for researching Eomecon chionantha, however, was for a different reason: to find a potential method to control fresh-water snails. Snails, particularly in Asia, Africa and South America, can carry the parasite that induces schistosomiasis, "the second most socioeconomically devastating parasitic disease after malaria". Posted by: Daniel Mosquin      Read more     Source

August 27, 2010, 7:28 AM CT

Complex interactions keep pests under control

Proponents of organic farming often speak of nature's balance in ways that sound almost spiritual, prompting criticism that their views are unscientific and naïve. At the other end of the spectrum are those who see farms as battlefields where insect pests and plant diseases must be vanquished with the magic bullets of modern agriculture: pesticides, fungicides and the like.

Which view is more accurate? A 10-year study of an organic coffee farm in Mexico suggests that, far from being romanticized hooey, the "balance and harmony" view is on the mark. Ecologists John Vandermeer and Ivette Perfecto of the University of Michigan and Stacy Philpott of the University of Toledo have uncovered a web of intricate interactions that buffers the farm against extreme outbreaks of pests and diseases, making magic bullets unnecessary. Their research is described in the July/recent issue of the journal BioScience.

The major players in the system-several ant species, a handful of coffee pests, and the predators, parasites and diseases that affect the pests-not only interact directly, but some species also exert subtle, indirect effects on others, effects that might have gone unnoticed if the system had not been studied in detail.

A key species in the complex web is the tree-nesting Azteca ant (Azteca instabilis). The ants aren't particular about the kind of tree they live in, but for some reason their nests are found in only about 3 percent of shade trees on the farm, and ant-inhabited trees aren't randomly distributed-they're found in clumps......... Posted by: Erica      Read more         Source

August 26, 2010, 7:22 AM CT

Move closer to making any crop drought-tolerant

Drought-tolerant crops have moved closer to becoming reality.

A collaborative team of researchers has made a significant advance on the discovery last year by the University of California, Riverside's Sean Cutler of pyrabactin, a synthetic chemical that mimics a naturally produced stress hormone in plants to help them cope with drought conditions.

Led by scientists at The Medical College of Wisconsin, the researchers report in Nature Structural & Molecular Biology (online) on Aug. 22 that by understanding how pyrabactin works, other more effective chemicals for bringing drought-resistance to plants can be developed more readily.

Abscisic acid versus pyrabactin

Plants naturally produced a stress hormone, abscisic acid (ABA), in modest amounts to help them survive drought by inhibiting growth. ABA has already been commercialized for agricultural use. But it has at least two disadvantages: it is light-sensitive and costly to make.

Pyrabactin, conversely, is relatively inexpensive, easy to make, and not sensitive to light. But its drawback is that, unlike ABA, it does not turn on all the "receptors" in the plant that need to be activated for drought-tolerance to fully take hold.

Lock and key

A receptor is a protein molecule in a cell to which mobile signaling molecules such as ABA or pyrabactin, each of which turns on stress-signaling pathways in plants may attach. Commonly at the top of a signaling pathway, the receptor functions like a boss relaying orders to the team below that then proceeds to execute particular decisions in the cell......... Posted by: Erica      Read more         Source