November 18, 2009, 11:16 PM CT

How crops survive drought

Breakthrough research done earlier this year by a plant cell biologist at the University of California, Riverside has greatly accelerated scientists' knowledge on how plants and crops can survive difficult environmental conditions such as drought.

Working on abscisic acid (ABA), a stress hormone produced naturally by plants, Sean Cutler's laboratory showed in April 2009 how ABA helps plants survive by inhibiting their growth in times when water is unavailable research that has important agricultural implications.

The Cutler lab, with contributions from a team of international leaders in the field, showed that in drought conditions certain receptor proteins in plants perceive ABA, causing them to inhibit an enzyme called a phosphatase. The receptor protein is at the top of a signaling pathway in plants, functioning like a boss relaying orders to the team below that then executes particular decisions in the cell.

Now recent published studies show how those orders are relayed at the molecular level. ABA first binds to the receptor proteins. Like a series of standing dominoes that begins to knock over, this then alters signaling enzymes that, in turn, activate other proteins resulting, eventually, in the halting of plant growth and activation of other protective mechanisms......... Posted by: Erica      Read more         Source

November 17, 2009, 8:05 AM CT

Plants prefer their kin

Plants don't mind sharing space with their kin but when they're potted with strangers of the same species they start invigorating their leaves, a study by McMaster University reveals.

The research, which appears in the current issue of the American Journal of Botany, suggests non-kin plants will not only compete underground for soil nutrients, but will attempt to muscle out the competition above ground in the ongoing struggle for light.

It follows prior research from McMaster University which observed that plants can recognize their kin through root systems and will compete more strongly for soil nutrients and water with non-sibling plants.

"This is the first study that shows plants are responding to kin at the above ground level," explains Guillermo Murphy, main author of the study and a graduate student in the Department of Biology at McMaster University. "When they recognize their kin, they grow differently in shape, taller, with more branches and fewer resources into leaves, therefore allowing their siblings to access precious sunlight."

When scientists planted seedlings of a North American species of shade-loving Impatiens in the same pot, they reacted mildly with other offspring from the same mother plant. But when planted among non-kin of the same species, the plants shift extra resources into growing leaves......... Posted by: Erica      Read more         Source

November 5, 2009, 8:42 AM CT

Making better broccoli

Carotenoidsfat-soluble plant compounds found in some vegetablesare essential to the human diet and reportedly offer important health benefits to consumers. Plant carotenoids are the most important source of vitamin A in the human diet; the carotenoids lutein and zeaxanthin, found in corn and leafy greens vegetable such as kale, broccoli, and spinach, are widely considered to be valuable antioxidants capable of protecting humans from chronic diseases including age-related macular degeneration, cancer, and cardiovascular disease.

Vegetables in the cabbage family (such as kale, cauliflower, and broccoli) have long been known as particularly good sources of dietary carotenoids. Recently, broccoli has emerged as the stand-out member of the species, providing more carotenoids to American consumers than any of its cabbage-family relatives. Yet, little has been understood about the carotenoid make-up of this popular green vegetableuntil now.

Mark W. Farnham of the U.S. Department of Agriculture, Agricultural Research Service, Charleston, South Carolina, and Dean A. Kopsell from the Plant Sciences Department, University of Tennessee, Knoxville, designed a research study aimed at finding out more about the carotenoid content of field-grown broccoli and determining the effects of genetics and the environment on carotenoid levels. The duo's research confirmed that broccoli heads contain abundant levels of lutein, an antioxidant usually thought to provide nutritional support to eyes and skin. Other carotenoids like beta-carotene, violaxanthin, neoxanthin, and antheraxanthin were also found in broccoli heads, but lutein was clearly the most significant, accounting for about half of all carotenoids measured......... Posted by: Erica      Read more         Source

November 5, 2009, 8:39 AM CT

Indoor plants to fight air pollution

Air quality in homes, offices, and other indoor spaces is becoming a major health concern, especially in developed countries where people often spend more than 90% of their time indoors. Surprisingly, indoor air has been reported to be as much as 12 times more polluted than outdoor air in some areas. Indoor air pollutants emanate from paints, varnishes, adhesives, furnishings, clothing, solvents, building materials, and even tap water. A long list of volatile organic compounds, or VOCs [including benzene, xylene, hexane, heptane, octane, decane, trichloroethylene (TCE), and methylene chloride], have been shown to cause illnesses in people who are exposed to the compounds in indoor spaces. Acute illnesses like asthma and nausea and chronic diseases including cancer, neurologic, reproductive, developmental, and respiratory disorders are all associated with exposure to VOCs. Harmful indoor pollutants represent a serious health problem that is responsible for more than 1.6 million deaths each year, as per a 2002 World Health Organization report.

Stanley J. Kays, Department of Horticulture, University of Georgia, was the lead researcher of a study published in HortScience that tested ornamental indoor plants for their ability to remove harmful VOCs from indoor air. As per Kays, some indoor plants have the ability to effectively remove harmful VOCs from the air, and not only have the ability to improve our physical health, but also have been shown to enhance our psychological health. Adding these plants to indoor spaces can reduce stress, increase task performance, and reduce symptoms of ill health......... Posted by: Erica      Read more         Source

November 5, 2009, 8:37 AM CT

Seeking flower variety

Florists and other retailers who sell flowers and plants can now add another tool to their marketing kit. A recent study of "consumption values" may help them understand what influences consumers' choices in regard to floral purchases, and how to better design marketing efforts and purchase stock that can increase customers and sales.

Li-Chun Huang from National Taiwan University and Tzu-Fang Yeh from Da-Yeh University headed a research project that reviewed the differences in floral consumption values across consumer groups (the full study appears in a recent issue of HortTechnology).

A consumer survey was conducted in cities and rural areas in Taiwan in 2006 where 677 participants were surveyed. As per responses to a survey question that asked whether they purchased flowers, participants were divided into two categories: ''users'' and ''nonusers'' of flowers.

The majority of survey participants indicated that the following values (in descending order) influenced their floral purchases: showing care to others, emotion conditioning, and "sensory hedonics", a phenomenon in which consumers perceive the value of flowers based on touching, smelling, or tasting them. Interestingly, those participants identified as "heavy users" of flowers revealed different priorities, rating "emotion conditioning" as more important than "showing care to others". The scientists note that this implies that "heavy users" make more frequent floral purchase flowers partly because they are more emotionally stimulated by flowers. Heavy users also rated "curiosity fulfillment" higher, leading to them to look for more novelty and variety when purchasing flowers......... Posted by: Erica      Read more         Source

November 4, 2009, 8:19 AM CT

Sustainably grown garlic

Consumer interest in new and diverse types of garlic is on the rise. Fueled by factors including the growth of the "local foods" movement, interest in world cuisines, and widespread reports touting its numerous health benefits, demand for high-quality, locally grown garlic is increasing throughout the U.S.

While most grocery stores in carry the familiar white, "softneck" garlic (which is most often imported), varieties of "hardneck" garlic in colorful hues of purple, magenta, pink, and white are becoming more available at local vegetable stands and through direct-marketing programs. The results of a recent study of 10 garlic cultivars can help farmers identify niche regional markets and offer new, in-demand garlic varieties to consumers.

Hundreds of garlic (Allium sativum L.) cultivars are available from seed companies, retailers, and germplasm collections. Increasingly, growers purchase bulbs from nonlocal sources and are often disappointed by unpredictable yields. Garlic bulbs resulting from seed stock purchased in other regions may not display the characteristicssuch as bulb size, shape, and colorfeatured in the catalogs.

Gayle M. Volk of the National Center for Genetic Resources Preservation, U.S. Department of Agriculture's Agricultural Research Service in Fort Collins, and David Stern of the Garlic Seed Foundation authored a study designed to determine which garlic traits are stable and which traits vary depending on where the garlic is grown. As per the study published in a recent issue of HortScience and funded primarily by the Northeast Sustainable Agricultural Research and Education program, previous research has shown that traits such as clove number, clove skin coloration, and topset number are representative of cultivar type across growth locations, whereas "phenotypic" traits such as bulb wrapper color, bulb size, and bulb elemental composition are specific to sites......... Posted by: Erica      Read more         Source

November 4, 2009, 8:16 AM CT

Pecan trees benefit from thinning

Pecan trees, like many fruit trees, have a tendency to bear fruit in cycles, producing a large crop in one or two years, followed by one or two years with little or no crop. This cycle, called "alternate bearing", is the most profit-limiting biological problem facing pecan producers; the inconsistent production pattern creates supply and marketing challenges that can have severe negative effects on the pecan industry.

Producers have experienced success using mechanical fruit thinning as a way to minimize the effects of alternate bearing on several pecan cultivars. While the protocol for mechanical crop thinning has been established for some pecan cultivars grown in Oklahoma and Kansas, little research has been conducted regarding the economic value and potential profitability of fruit thinning of cultivars found in the southeastern United States. To address this issue, researchers at the University of Georgia's Department of Horticulture studied the effects of mechanical fruit thinning on pecan yield, nut quality, and profitability using 'Sumner' and 'Cape Fear' pecan trees, two important cultivars prevalent in areas of the southeastern U.S. The research study was published in a recent issue of HortTechnology

Ten 20-year-old trees of both 'Sumner' and 'Cape Fear' were used for the study. Trees grown in Tifton loamy sand soil in a commercial pecan orchard in Irwin County, Georgia, were used for the study. The trees were spaced 40 x 40 feet and were drip-irrigated. Treatments were replicated five times in a randomized complete-block design. Five trees of each cultivar were mechanically thinned using a tree shaker with a hydraulic shaker heada process called trunk shakingto remove 30% to 40% of the fruit on each tree, and five trees were not thinned......... Posted by: Erica      Read more         Source

November 4, 2009, 8:15 AM CT

For African violets

African violets have a mixed reputation. Their delicate, colorful flowers and furry, soft leaves make them a favorite among home gardeners and growers. But the striking plants are often regarded as temperamental: a precise recipe of light, moisture, warm temperatures, high humidity, and fertilizer is mandatory to encourage african violets to grow and flower.

A recently published study by researchers Julia C. Brotton and Janet C. Cole from the Department of Horticulture and Landscape Architecture at Oklahoma State University (in a recent issue of HortTechnology) could provide african violet enthusiasts with important care information about the finicky flower.

Because of their brightly colored flowers and hairy leaves, people are attracted to african violets and often want to touch the leaves and flowers. But how does all this attention affect the plants? The research team set out to determine the effect of "brushing" african violet leaves on plant growth and quality. Cole explained, "Because (african violet) growers work in conditions that can contribute to the development of dry, irritated skin, a number of growers use body lotions to help soothe and moisturize their dry skin. A number of consumers also use these products. Our study researched whether touching or "brushing" african violet leaves causes damage, especially when body lotion or other skin care products have been applied to hands before touching the plants"......... Posted by: Erica      Read more         Source

October 20, 2009, 10:19 PM CT

New method to help keep fruit and vegetables fresh

ATLANTA Did you know that millions of tons of fruits and vegetables in the United States end up in the trash can before being eaten, as per the U.S. Department of Agriculture?

A Georgia State University professor has developed an innovative new way to keep produce and flowers fresh for longer periods of time.

Microbiologist George Pierce's method uses a naturally occurring microorganism no larger than the width of a human hair to induce enzymes that extend the ripening time of fruits and vegetables, and keeps the blooms of flowers fresh. The process does not involve genetic engineering or pathogens, but involves microorganisms known to be linked to plants, and are considered to be helpful and beneficial to them.

"These beneficial soil microorganisms serve essentially the same function as eating yogurt as a probiotic to have beneficial organisms living in the gastrointestinal system," Pierce said.

The process works by manipulating the organism's diet so that it will over express certain enzymes and activities that work in the ripening process and keeping the flower blooms fresh. Pierce analogizes this to using diet and exercise to improve the performance of an athlete.

"We change the diet of the organism, and we can change its performance," Pierce said. "It's no different than taking a good athlete and putting them on a diet and exercise regime, and turning him or her into a world-class athlete"......... Posted by: Erica      Read more         Source

October 20, 2009, 8:48 AM CT

Carbon-offsetting and conservation

Logged rainforests can support as much plant, animal and insect life as virgin forest within 15 years if properly managed, research at the University of Leeds has found.

Because trees in tropical climates soak up large amounts of carbon dioxide, restoring logged forest through planting new trees could also be used in carbon trading, as per Dr David Edwards, from University's Faculty of Biological Sciences.

Dr Edwards is calling for the inclusion of biodiversity-friendly strategies in carbon trading schemes to ensure that carbon off-setting projects support, rather than undermine, rainforest conservation.

Currently, large plantations of one type of tree, such as Eucalpytus, are popular as carbon off-setting or sequestration projects in the tropics because they also provide commercial benefits, but they do not support tropical biodiversity.

But Dr Edwards has shown that managed restoration of logged forest which can also be used for carbon off-setting brings biodiversity virtually back to pre-logging levels within 15 years, much quicker than forest left to regenerate naturally.

"Our research shows that it is possible to have both carbon sequestration and biodiversity benefits within the same scheme," he said.

"This could act as a strong incentive to protect logged forests under threat of deforestation for oil palm and other such crops. Selectively logged rainforests are often vulnerable because they're seen as degraded, but we've shown they can support similar levels of biodiversity to unlogged forests"......... Posted by: Erica      Read more         Source

October 13, 2009, 8:18 AM CT

Rainforest Plants Then and Now

Smithsonian scientists working in Colombia's Cerrejn coal mine have unearthed the first megafossil evidence of a neotropical rainforest. Titanoboa, the world's biggest snake, lived in this forest 58 million years ago at temperatures 3-5 C warmer than in rainforests today, indicating that rainforests flourished during warm periods.

"Modern neotropical rainforests, with their palms and spectacular flowering-plant diversity, seem to have come into existence in the Paleocene epoch, shortly after the extinction of the dinosaurs 65 million years ago," said Carlos Jaramillo, staff scientist at the Smithsonian Tropical Research Institute. "Pollen evidence tells us that forests before the mass extinction were quite different from our fossil rainforest at Cerrejn. We find new plant families, large, smooth-margined leaves and a three-tiered structure of forest floor, understory shrubs and high canopy."

Historically, good rock exposures and concentrated efforts by paleontologists to understand the evolution of neotropical rainforestsone of the most awe-inspiring assemblages of plant and animal life on the planethave been lacking. "The Cerrejn mining operation is the first clear window we have to see back in time to the Paleocene, when the neotropical rainforest was first developing," said Scott Wing, a paleontologist from the Smithsonian's National Museum of Natural History......... Posted by: Erica      Read more         Source

Mon, 28 Sep 2009 04:06:31 GMT

Grow your own apples

Choose a location that offers 8 hours of sun per day (trees in shady areas won"t produce ample fruit).

For pollination to occur, you need to plant at least two trees within 3 o 4 m of one another.

Well-drained soil is very important since too much moisture will harm the roots of both new and established trees.

Likewise, the soil needs to be rich; abundant nutrients are essential for a bountiful crop, so when planting, work compost, bonemeal or bloodmeal into the planting holes dug for each sapling.

To maintain richness in the soil, add compost each fall or spring around the base of the trees as far out as the drip line; top up with mulch except near the trunk where excessive moisture can cause rot.

Each fall clear fallen fruits from around the base of the trees to minimize the occurrence of apple maggots and other pests that can ruin the next crop of fruit

This wraps up apple week! Check out 10 tasty ways to eat apples for more suggestions on how to make the most of the season.

Posted by: danamccauley      Read more     Source

September 20, 2009, 7:12 PM CT

Bananas Gone Bad Glow Blue in UV-Light

Nicholas Turro of Columbia University, Bernhard Krautler of the University of Innsbruck, Austria and their colleagues have observed that, as chlorophyll ages and begins to disintegrate in banana peels it does not change color in the spectrum of visible light we see. Instead, it glows blue when observed under ultraviolet light.

While the light show adds a level of exoticism to the fruit in our eyes, and serves to attract a host of potential consumers in the eyes of insects and other animals who can appreciate the UV, the display is equally exciting to chemists. Because the glowing molecules occur in close proximity to dying tissue, they promise to be a literal beacon for the further study of the way organisms cleanse themselves of dying cells, or programmed cell death. A well known and poorly understood condition in which programmed cell death malfunctions is cancer.

Turro and colleagues describe how ordinary brown spots that form on bananas as they transition from ripe to rotten, each show a glowing blue halo in UV, caused by the congregation of chlorophyll breakdown byproducts. Their research appears in the Proceedings of the National Academies of Science.

Chlorophyll is the molecule that makes much of the life on earth possible. It is the integral ingredient that allows plants to take in a mixture of carbon dioxide, water and sunlight and convert it to oxygen, sugars and starches. These are the same sugars and starches we eat every time we fix a salad, and the same oxygen that we breathe......... Posted by: Erica      Read more         Source

September 15, 2009, 9:23 PM CT

Unlocking genetic secrets of date palm

Scientists at Weill Cornell Medical College in Qatar have mapped a draft version of the date palm genome, unlocking a number of of its genetic secrets.

"We have generated a draft DNA sequence and initial assembly of the date palm using the most advanced technology," says Joel Malek, director of the Genomics Laboratory at WCMC-Q. Genetic information about the date palm is extremely valuable to scientists who are working to improve fruit yield and quality and to better understand susceptibility and resistance to disease.

"This is an important step for our biomedical research program," says Khaled Machaca, Ph.D., professor of physiology and biophysics and associate dean for basic science research. "It clearly demonstrates the feasibility and success of the most advanced genomics technologies in Qatar and represents a milestone towards establishing Qatar and Weill Cornell as a regional research center of excellence. In addition, this achievement by the WCMC-Q research team holds great promise for the application of the genomics technology to a better understanding of biomedical problems".

The date palm sequencing work was a proof of concept study, as per Malek, who established the genomics laboratory last year. The goal was to establish and validate the capabilities of the core lab for large-scale genomics projects. The lab is an integral part of a large biomedical research program launched last year by WCMC-Q with support from the Qatar Foundation that aims to make Qatar a hub for research in the Middle East......... Posted by: Erica      Read more         Source

September 15, 2009, 9:19 PM CT

Drug-free Cannabis plant

In a first step toward engineering a drug-free Cannabis plant for hemp fiber and oil, University of Minnesota scientists have identified genes producing tetrahydrocannabinol (THC), the psychoactive substance in marijuana. Studying the genes could also lead to new and better drugs for pain, nausea and other conditions.

The finding is reported in the recent issue of the Journal of Experimental Botany Main author is David Marks, a professor of plant biology in the College of Biological Sciences.

The study revealed that the genes are active in tiny hairs covering the flowers of Cannabis plants. In marijuana, the hairs accumulate high amounts of THC, whereas in hemp the hairs have little. Hemp and marijuana are difficult to distinguish apart from differences in THC.

With the genes identified, finding a way to silence themand thus produce a drug-free plant comes a step closer to reality. Another desirable step is to make drug-free plants visually recognizable. Since the hairs can be seen with a magnifying glass, this could be accomplished by engineering a hairless Cannabis plant.

The scientists are currently using the methods of the latest study to identify genes that lead to hair growth in hopes of silencing them.

"We are beginning to understand which genes control hair growth in other plants, and the resources created in our study will allow us to look for similar genes in Cannabis sativa," said Marks......... Posted by: Erica      Read more         Source

September 15, 2009, 2:45 PM CT

Exotic timber plantations use water

Ecologists have discovered that timber plantations in Hawaii use more than twice the amount of water to grow as native forests use. Particularly for island ecosystems, these findings suggest that land management decisions can place ecosystems and the people who depend on them at high risk for water shortages.

"Researchers used to believe that forests in same environments use water in the same way," says Lawren Sack of The University of California at Los Angeles, who coauthored the study with graduate student Aurora Kagawa in the recent issue of the ESA journal Ecological Applications "Our work shows that this is not the case. We need to know the water budget of our landscape, from gardens to forests to parks, because water is expensive".

Eventhough forests like these Hawaiian timber plantations can be valuable for their contributions to human society, such as fiber, fuel and carbon sequestration, they are dominated by non-native vegetation.

Kagawa, Sack and their colleagues compared the water use of trees in native forests, composed mostly of native ohia trees, with water use in timber plantations containing exotic eucalyptus and tropical ash. The team inserted heated and unheated probes into the trees' trunks and monitored the temperature differences between the two as sap flowed past them. This technique allowed them to determine the rate of sap flow through the tree. A faster flow rate means that the tree is using more water......... Posted by: Erica      Read more         Source

September 15, 2009, 2:29 PM CT

More tamarisk invasion in future

If the future warming trends that researchers have projected are realized, one of the country's most aggressive exotic plants will have the potential to invade more U.S. land area, as per a newly released study reported in the current issue of the journal Invasive Plant Science and Management The study observed that tamariskprevalent today in some parts of the region, but generally limited to warm and dry environmentscould expand its range into currently uninvaded areas.

"Results of our study suggest that a little over 20 percent of the Northwest east of the Cascade Mountains supports suitable tamarisk habitat, but less than one percent of these areas is currently occupied by the species," said Becky Kerns, a research ecologist with the Western Wildland Environmental Threat Evaluation Center (WWETAC) who led the study. "That means the remainder is highly vulnerable to invasion right now with the situation potentially getting worse as favorable conditions for tamarisk may expand under climate change".

These findings translate into a two- to ten-fold increase in highly suitable tamarisk habitat in Oregon, Washington, and Idaho by the end of the century.

Tamarisk, also known as "saltcedar," is a deciduous shrub or small tree that grows quickly, reproduces profusely, and tolerates drought and salty conditions, making it capable of easily displacing native species. It also sheds flammable leaves that serve as potential fuel, significantly increasing an area's wildfire risk. The plant was intentionally introduced to the West in the 1800s as an ornamental, windbreak, shade, and erosion control species and today can be found growing prolifically in the Northwest in the central Snake River Plain, Columbia Plateau, and Northern Basin and Range......... Posted by: Erica      Read more         Source

September 15, 2009, 7:51 AM CT

Clues into the evolution of the first flowers

Approximately 120-130 million years ago, one of the most significant events in the history of the Earth occurred: the first flowering plants, or angiosperms, arose. In the late 1800s, Darwin referred to their development as an "abominable mystery." To this day, researchers are still challenged by this "mystery" of how angiosperms originated, rapidly diversified, and rose to dominance. (See the January 2009 issue of the American Journal of Botany at www.amjbot.org/content/vol96/issue1.).

Studies of key features of angiosperm evolution, such as the evolution of the flower and development of the endosperm, have contributed to our current understanding of relationships among the early families of flowering plants. Examining the development of seeds and embryos among early angiosperms may help to improve our understanding of how flowering plants evolved from the nonflowering gymnosperms.

A recent study by Dr. Paula Rudall and his colleagues reported in the recent issue of the AJB (www.amjbot.org/cgi/content/full/96/9/1581) explores a piece of this mystery: the microscopic anatomy of seed development in Trithuria, a genus in the plant family Hydatellaceae, believed to be one of the earliest families of angiospermsthe so-called "basal angiosperms".

Rudall and his colleagues' observations of the development of the embryo and endosperm (tissue that surrounds the embryo and provides nutrition) in Trithuria suggest that double fertilization occurs. Double fertilization is a unique feature of flowering plants where one sperm nucleus unites with the egg, producing the embryo, while another sperm nucleus unites with a separate nucleus from the female, producing the endosperm. The endosperm is divided into two regionsthe micropylar and chalazal regions......... Posted by: Erica      Read more         Source

September 15, 2009, 7:45 AM CT

Conflict between plant and animal hormones

Cis-OPDA (12-oxophytodienoic acid) is a highly reactive plant hormone which simultaneously serves as a precursor molecule of the metabolic "master switch" jasmonic acid. Both signal herbivory in leaves and shoots of plants and activate the plants' defense reaction against caterpillars. Cis-OPDA, when reaching the hemolymph of the caterpillar, has a negative effect on the animal, leading to premature pupation and, apparently, an impaired immune system.

Paulina Dabrowska, one of the very first PhD students of the Jena International Max Planck Research School (IMPRS) who meanwhile earned her PhD, studied the whereabouts of plant hormones after they had been consumed by the caterpillars and had passed the insect gut. Are the hormones, which are known to severely influence development and metabolism of organisms even in the slightest dose, fully metabolized in the insect gut, just converted, or not influenced at all?

Studying the plant hormone cis-OPDA it became quickly evident that a conversion of the molecule must have taken place in the insect gut. The young chemist, originally from Poland, discovered that an enzyme must play a role in the chemical reaction observed: "First, we observed that cis-OPDA was not present in the insect feces anymore. Instead of cis-OPDA, our mass spectrometers suggested iso-OPDA. However, iso-OPDA is only constituted by means of enzyme catalysis." Control experiments, solely performed in strong alkaline solutions as present in the insect gut (pH approx. 10), did not cause a cis-iso conversion. The test animals were Spodoptera littoralis (cotton leaf worm) and Helicoverpa armigera (cotton bollworm) larvae; both species are major cotton pests worldwide......... Posted by: Erica      Read more         Source

September 14, 2009, 11:55 PM CT

For carnivorous plants, slow but steady wins the race

Like the man-eating plant in Little Shop of Horrors, carnivorous plants rely on animal prey for sustenance. Fortunately for humans, carnivorous plants found in nature are not dependent on a diet of human blood but rather are satisfied with the occasional fly or other insect. The existence of carnivorous plants has fascinated botanists and non-botanists alike for centuries and raises the question, "Why are some plants carnivorous?" .

A recent article by Drs. Jim Karagatzides and Aaron Ellison in the recent issue of the American Journal of Botany (www.amjbot.org/cgi/content/full/96/9/1612) addresses this question. As Ellison stated, "The general answer to this is that in environments that have few nutrients (such as bogs, where we study carnivorous plants), carnivory allows these plants to capture nutrients 'on the wing'. But if it's so good to be a carnivorous plant in these kinds of environments, why aren't there more carnivorous plants? Knowing how much it 'costs' a carnivorous plant to make a trap is a key piece of information needed to understand why there aren't more carnivorous plants".

Elllison and Karagatzides simultaneously measured both costs and benefits for traps, leaves, roots, and rhizomes of 15 different carnivorous plant species, including pitcher plants and the Venus fly trap. By measuring the construction cost of carbon needed to create these plant structures and comparing it to the payback timethe amount of time the structure takes to photosynthesize to recoup the carbon used in its constructionEllison and Karagatzides were able to determine how beneficial a trap might be to a plant......... Posted by: Erica      Read more         Source

September 11, 2009, 7:33 AM CT

As ash borer claims more trees

Mark Widrlechner may someday be known as the modern-day Johnny Appleseed for ash trees.

As the devastating insect emerald ash borer is working its way across North America destroying almost all the native ash trees it encounters, Widrlechner is rapidly collecting and storing ash tree seeds.

Like the legendary Appleseed who planted apple trees across the country, Widrlechner's seed stocks can serve as a national source for reintroducing ash trees once the devastation can be controlled.

Widrlechner, horticulturist for the United States Department of Agriculture's Agricultural Research Service (ARS) and assistant professor of agronomy and horticulture at ISU, is a curator at the North Central Regional Plant Introduction Station in Ames, Iowa, responsible for collecting and maintaining seeds for several species of trees, including ash, for the USDA's National Plant Germplasm System.

As the pest devours ash tree populations on its way across North America, there may soon be few, if any, ash trees left.

"Where these borers have been present the longest, it has basically been a total wipeout," said Widrlechner.

"That is something we rarely see in nature," he said. "It's uncommon for a pest to come in and just clean something out. It doesn't just attack sick trees. Emerald ash borer attacks healthy trees. It attacks small trees. So you don't have just big, old trees falling to this, you've got 2 to 3 inch saplings falling to this."........ Posted by: Erica      Read more         Source

September 10, 2009, 7:06 AM CT

Getting plants to rid themselves of pesticide residues

Researchers in China are reporting the "intriguing" discovery that a natural plant hormone, applied to crops, can help plants eliminate residues of certain pesticides. The study is scheduled for the Sept. 23 issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

Jing Quan Yu and his colleagues note that pesticides are essential for sustaining food production for the world's growing population. Farmers worldwide use about 2.5 million tons of pesticides each year. Researchers have been seeking new ways of minimizing pesticide residues that remain in food crops after harvest with little success. Prior research suggested that plant hormones called brassinosteroids (BRs) might be an answer to the problem.

The researchers treated cucumber plants with one type of BR then treated the plants with various pesticides, including chloropyrifos (CPF), a broad-spectrum commercial insecticide. BR significantly reduced their toxicity and residues in the plants, they say. BRs appears to be "promising, environmentally friendly, natural substances suitable for wide application to reduce the risks of human and environmental exposure to pesticides," the researchers note. The substances do not appear to be harmful to people or other animals, they add......... Posted by: Erica      Read more         Source

August 28, 2009, 7:01 AM CT

DNA from Linnaeus' botanical collections

Scientists at Uppsala University has succeeded in extracting long DNA fragments from dried, pressed plant material collected in the 1700s by Linnaeus' apprentice Adam Afzelius. It is hoped that the study, led by Associate Professor Katarina Andreasen, will shed light on whether plants growing today at Linnaeus' Hammarby estate outside Uppsala reflect the species cultivated by Linnaeus himself.

A large number of plants of uncertain provenance grow at Carl Linnaeus' Hammarby estate, a museum and popular tourist destination. Have they been present since Linnaeus' time? In addition to probing this question, the current study will test the limits of DNA-sequencing methods with regard to old plant material and has already demonstrated that it is possible to sequence plant material more than 200 years old. The study is now reported in the scientific journal Taxon

"This opens up many exciting research possibilities in connection with material from herbaria throughout the world", says Katarina Andreasen.

The scientists hopes to initiate corresponding DNA investigations of plant material from the garden at Hammarby as soon as possible.

"It would be fun, if we can show that the old material is genetically identical with the plants currently growing at Hammarby, to create a living herbarium for summer visitors to the garden", says Katarina Andreasen......... Posted by: Erica      Read more         Source