Science 24×7
Latest Science News

Roses have long been a favorite of gardeners, but they often require a lot of work to thrive. And the emphasis on organics has more home gardeners concerned about the environment and reluctant to use pesticides.

W. A. Mackay of Texas A&M University led a study comparing several varieties of roses to determine which grow best with minimal care under certain conditions. The results were published in the American Society for Horticultural Science journal HortTechnology.

Flower number, flower size, visual estimate of flowering percentage, plant vigor and overall plant performance were rated for 116 varieties of roses from Spring 2000 through 2002. No pesticides or fertilizers were used to grow the roses. Four plants represented each variety, and only varieties with three or four plants surviving the experiment were used in the statistical analysis.

Additional tests were run on a subset of rose varieties to assess their nutrient levels. Monthly recordings were also taken to rate each variety’s disease resistance by noting symptoms of petal blight, powdery mildew, and black spot, some of the most common ailments of roses. Plants that were grown on their own roots had significantly better appearance ratings and survival rates than plants that were grafted.

Caption: This is Belinda’s Dream, one of the original EarthKind Roses.

Credit: Photo by Claude Grave Read More

Deficit irrigation is an agricultural technique used to achieve a variety of results depending on the crop. For white wine grapes, it balances the crop load by limiting the canopy size so there aren’t too many leaves shading the grapes. For red wine grapes, deficit irrigation again limits canopy size, but also affects berry components associated with wine quality.

A drawback of this canopy-limiting process is that fruit can become sunburned, especially under sunny, arid conditions, which can adversely affect productivity and fruit maturity. A particle film, which increases light reflection and reduces leaf temperature, has been tested on several crops. It acts as a sunscreen by reflecting the harmful ultraviolet rays off of the leaves and fruit, but still allows the right radiation for photosynthesis through to nourish the plant.

Krista Shellie of the U.S. Department of Agriculture led a study to learn more about foliar particle film’s effects on wine grapes when the grapes were grown under varying levels of water stress. The study, published in the American Society for Horticultural Science journal HortScience, also noted particle film’s effect on grape yield and maturity. Grapes were grown according to commercial practice with the exception of the watering schedule and application of the particle film. Film effectiveness was monitored by measuring the amount of leaf gas exchange, but particle film’s influence on this process seemed to differ depending on the amount of water stress the vine was experiencing.

Caption: This particle film is used to protect wine grapes from heat and drought.

Credit: Photo by Krista Shelli Read More

Apples have long been associated with good health, including lower risks of cancer and cardiovascular disease. Apples also contain anthocyanins, important antioxidants that give the peels their red coloring. Redness is one of the most important factors consumers consider when buying apples.

One variety of apple called ‘Honeycrisp’ has peel pigment that takes on one of two patterns—”striped” or “blushed.” A single ‘Honeycrisp’ tree can produce both striped and blushed apples, a phenomenon unique to this variety. In terms of marketability, consumers in some regions prefer striped apples, while others prefer blushed, but overall redder is better.

Adriana Telias, Emily Hoover, and Diego Rother of the University of Minnesota published a research study in the American Society for Horticultural Science journal HortScience comparing the coloring of ‘Honeycrisp’ apples.

Caption: This computer measures the amount of blush or stripe in a peel of “honeycrisp” apple.

Credit: Photo by Adriana Telias

From 2005

Greenhouses are an integral part of U.S. agriculture. Nearly $200 million of food is produced in domestic greenhouses each year, and the facilities play a vital role in producing seeds and transplantable vegetation. Understanding how to keep greenhouse plants healthy can translate to increased revenue for producers.

Kenneth R. Summy of the University of Texas-Pan American and Christopher R. Little of Kansas State University (Manhattan) led a study examining the stresses of a variety of greenhouse plants. The study, published in the August 2008 issue of HortScience, used color infrared (CIR) photography.

CIR images are divided into wavebands. Ratios are created comparing the NIR wavebands to red wavebands. High NIR and low red values are typical of healthy vegetation because light is being reflected in the proper proportion. Ratios of colors accentuate even slight differences in light reflection, which can indicate disease.

Caption: Color infrared (CIR) photography is used to detect diseases in greenhouse plants.

Credit: Photo by Chris Little

Trifoliate orange, ‘Valencia’ orange, sour orange, grapefruit, ‘Bo’ tree, and muskmelon were infested with sooty mold, insects, and pathogens; all are common ailments in greenhouses. Leaves exhibiting a range of symptoms were chosen to compare with healthy leaves of the same species and photographed using CIR. Read More

Coordination becomes difficult, items disappear, keeping new information in the mind is impossible. Worldwide almost 30 million people suffer from Alzheimer’s disease, a neurodegenerative, irreversible ailment which starts with memory gaps and ends in helplessness and the loss of personality. The most critical factor in developing Alzheimer’s disease is age. Most cases occur after the age of 65.

Two hallmarks are typical for Alzheimer affected brains. One of them, located between nerve cells, is amyloid plaques - extracellular protein aggregates mainly composed of a protein named beta-amyloid. The other clue is intracellular tau fibrils. In the interplay with genetic factors, the latter contribute to a disordered communication within the cell. This triggers cell death.
Read More

In comparison to many other living creatures, flies tend to be small and their brains, despite their complexity, are quite manageable. Scientists at the Max Planck Institute of Neurobiology in Martinsried have now ascertained that these insects can make up for their low number of nerve cells by means of sophisticated network interactions. The neurobiologists examined nerve cells that receive motion information in their input region from only a narrow area of the fly’s field of vision. Yet, thanks to their linking with neighbouring cells, the cells respond in their output regions to movements from a much wider field of vision. This results in a robust processing of information. Nature Neuroscience, February 8, 2009.

The complexity of the human brain is remarkable: It contains billions of nerve cells, each of which is connected with its neighbours via many thousands of contacts. The result is a multifaceted network which stores and processes many types of information. In comparison, the brain of a fly seems fairly simple with its 250 000 nerve cells. For example, a small network of only 60 nerve cells in each cerebral hemisphere suffices the blowfly to integrate visual motion information. The resulting information is then used in the control and correction of the fly’s flight manoeuvres. However, flies clearly demonstrate just how efficient these 60 cells actually are when they dodge obstacles while flying at high speed and land upside-down on the ceiling. No wonder neurobiologists find the brain of the fly so fascinating!

Caption: Job sharing in the flight control center: Each VS nerve cell receives visual information in its input region (broad cell end) from only a narrow strip of the fly’s eye (the cell’s receptive field). In the output region at the rear end of the cell, electrical connections (red) enable the cells to communicate with neighboring cells.

Credit: Image: Max Planck Institute of Neurobiology / Schorner Read More

Round, oblong, and in-between: the shapes of the fruits we eat are not always coincidental or, for that matter, thanks to nature. Before fruit arrives in local groceries, a lot of time and effort may have gone into creating the varieties found in the produce section.

In the mid-1960s, Dr. James N. Moore of the University of Arkansas began a grape breeding program, working toward developing varieties with elongated shapes. Now, 40 years later, Dr. John R. Clark continues this effort. One of these unique-shaped developments has been researched further, first to characterize the shape variation, with subsequent work to find genetic markers that could help breeders produce elongated grapes without waiting years to see the actual fruit on the vine.

Classifying fruit as elongated or other shapes can be challenging, as visual observations can be highly subjective and ratings often variable among observers.

Caption: Digital analysis is used to characterize the shapes of grapes.

Credit: Photo by John R. Clark

Recently, a digital method for analyzing shapes has been used for tomatoes, but this method requires each fruit to be cut in half and scanned to take the measurements, making the fruit unusable for additional studies or for eating.

Another digital analysis method, called SigmaScan®, is in use at the University of Arkansas’ turfgrass science program. SigmaScan® selects colors within a given range of a photograph to analyze turf quality mechanically, eliminating human error. Read More

As the popularity of organic produce increases with consumers, growers need more options to manage pests naturally.

John D. Sedlacek and Gary R. Cline (retired) of the Land Grant Program at Kentucky State University led a research project designed to investigate options for reducing the presence of cucumber beetles. These pests damage crops by eating the roots, shoots, and flowers, and transmit the bacterial wilt pathogen. The study, published in the American Society of Horticultural Science journal HortTechnology, compares several practices in watermelon and muskmelon crops. Read More

Since around 1960, methyl bromide (MB) has been the foundation for soilborne disease and weed control in California strawberries. MB, classified as a Class I stratospheric ozone-depleting chemical, has been phased out since 2005, but is still being used in strawberry production under a critical-use exemption.

Strawberry production is important to California’s economy; the state leads the U.S. in strawberry production. In 2006, the fruit harvest yielded a value of $1.2 billion, and accounted for 79% of the total U.S. gross sales.

The diversity of climates in California along with the use of this fumigant, permits the production of high-quality runner plants, which are propagated in virus-free growing facilities called “screenhouses”. Plants are reared first in a low-elevation facility during the warm early season, and then moved to higher-elevation facilities for cool, late-summer conditions. This process ensures that strawberry plants will be ready to transplant into fruit fields by early fall. Read More

Plant cells communicate via microscopic channels called plasmodesmata that are embedded in their cell walls. For the stem cells in the plants’ growing tips, called “meristems,” the plasmodesmata are lifelines, allowing nutrients and genetic instructions for growth to flow in.

Developmental and environmental cues trigger changes in the structure of the tiny channels, thereby altering the flow of traffic through them. The genes and molecular pathways of the plant cell that respond to these cues, and the mechanisms that control channel structure and cell-to-cell traffic are, however, mostly unknown. Read More

Introducing ‘Natchez’, the twelfth release in a series of erect-growing, high-quality, productive, floricane-fruiting blackberry (Rubus L. subgenus Rubus Watson) cultivars developed by the University of Arkansas.

John R. Clark and James N. Moore of the Department of Horticulture at the University of Arkansas introduced ‘Natchez’ in the October 2008 issue of the American Society of Horticultural Science’s journal HortScience. According to Clark, the new blackberry is a result of a cross of Ark. 2005 and Ark. 1857 made in 1998. The original plant was selected in 2001 from a seedling field at the University of Arkansas Fruit Research Station in Clarksville, and tested as selection Ark. 2241. Read More

Canopy light interception (LI) is an important factor for crop growth and fruit yield. Crop yield depends on a canopy’s ability to intercept incident solar radiation, which in turn depends on the available leaf area, its structure, and its efficiency in the process of photosynthesis.

Maximizing leaf growth through light interception is an important consideration when studying different agricultural or environmental factors on crop yield, and it is the main source of data in the most widely used methods for estimating crop water needs. Read More

The toxic gas formaldehyde is contained in building materials including carpeting, curtains, plywood, and adhesives. As it is emitted from these sources, it deteriorates the air quality, which can lead to “multiple chemical sensitivity” and “sick building syndrome”, medical conditions with symptoms such as allergies, asthma, and headaches. The prevalence of formaldehyde and other volatile organic compounds (VOC) is greater in new construction.

Researchers are studying the ability of plants to reduce formaldehyde levels in the air. A study led by Kwang Jin Kim of Korea’s National Horticultural Research Institute compared the absorption rate of two types of houseplants. The results of the experiment on Weeping Fig (Ficus benjamina) and Fatsia japonica, an evergreen shrub, were published in the Journal of American Society for Horticultural Science. Read More

Washington’s famous apple industry brought in $1.4 billion in 2006, but a disease is cutting into those profits.

Lenticel breakdown disorder, known as LB, creates brown spots and indentations most commonly on the ‘Gala’ variety of apple, but these signs don’t show up until after apples are harvested, stored, and processed. Time and materials are spent on fruit that can’t be sold, and if a shipment goes out before symptoms are detected, the reputation of the grower is jeopardized.

Researchers at the U.S. Department of Agriculture, led by Eric A. Curry, are looking for ways to reduce the incidence and/or severity of LB in ‘Gala’ apples. The study, published in the October-December 2008 issue of HortTechnology, compared several coatings sprayed on apples in three commercial orchards with a history of LB. Read More

Plants are essential to our survival and that of most other animals on earth. It is easy to overlook this fact because they have become discretely embedded into our everyday lives. Plants provide us with food, medicines, and raw materials used by our industries. In spite of their importance, very few of us could name more than a tiny fraction of the plants that surround us. True, most would have little difficulty in distinguishing between a buttercup from a dandelion (provided both are in flower) but only a hand full of experts could identify all 1600 native plants in the UK, and nobody is able to name all of the 250,000 or so plant species recorded world-wide. Accurate plant identification on a large scale is nevertheless vital if we are to protect the most biodiverse regions of the world. Equally, plant identification based on DNA could help in the search for new sources of pharmaceutical drugs, check ingredients in food and industrial products or provide a new source of forensics information for criminal investigations. Read More

Researchers at the Gladstone Institute of Cardiovascular Disease (GICD) and the University of California, San Francisco have unraveled a complex signaling process that reveals how different types of cells interact to create a heart. It has long been known that heart muscle cells (cardiomyocytes) actively divide and expand in the embryo, but after birth this proliferative capacity is permanently lost. How this transition occurs has not been known. In the current issue of the journal Developmental Cell, the scientists show that the secret to this switch lies in the cells that surround the muscle cells, known as fibroblasts, which send signals that tell cardiomyocytes to divide or get bigger in size. Manipulation of these signals may be able to induce cardiomyocytes to divide again for regenerative purposes after heart attacks. Read More

New research reveals a critical cellular signaling pathway that is responsible for generating excess connective tissue in multiple organs, similar to what is seen in human patients with scleroderma. The study, published by Cell Press in the February issue of the journal Developmental Cell, also reveals an intriguing but unexpected regulatory role for a tumor suppressor gene in fibrotic disease.

Platelet derived growth factors (PDGF) regulate the proliferation, survival, migration and differentiation of cells and play a critical role during embryonic development. However, the consequences of excess PDGF signaling are not very well understood. Read More

Current research suggests that inflammation increases the risk of plaque rupture in atherosclerosis. The related report by Ovchinnikova et al, “T cell activation leads to reduced collagen maturation in atherosclerotic plaques of ApoE-deficient- mice,” appears in the February 2009 issue of The American Journal of Pathology.

Atherosclerosis is a disease of arterial blood vessels where fats, cholesterol, blood cells, and fibers form hardened plaques on the artery wall. These plaques restrict blood flow to tissues such as the heart and brain by narrowing the artery. Atherosclerosis can be caused by high blood pressure, high fat and high cholesterol diets, smoking, and diabetes. People with atherosclerotic plaques often show no symptoms for decades. Read More

Scientists have shown that HIV faces a genetic “bottleneck” when the virus is transmitted heterosexually from one person to another, by way of the genital mucosa. The results, published January 23 in the open-access journal PLoS Pathogens, explain why prior infection by other sexually-transmitted diseases (STDs) makes individuals more susceptible to HIV infection.

The team of researchers, lead by Eric Hunter of Emory University, identified 20 heterosexual couples soon after infection occurred and obtained viral genetic sequences from both partners. They examined the most variable region of the virus’ env gene, which encodes a protein forming the outer coat of the virus. Approximately 90% of the couple recipients were found to be infected by a single viral variant of HIV-1. However, that variant was not the same in each case. Read More

Like guards controlling access to a gated community, nuclear pore complexes are communication channels that regulate the passage of proteins and RNA to and from a cell’s nucleus. Recent studies by researchers at the Salk Institute for Biological Studies offer new insights about the pores’ lifespan and how their longevity affects their function.

Their findings, reported in the Jan. 23 issue of Cell, may provide clues to one of the most enduring questions of biology: how and why cells age. They also offer a new, promising avenue of investigation for scientists pursuing intervention strategies for neurodegenerative diseases.

Caption: In aging cells one of the proteins composing nuclear pores becomes damaged and molecules that should be restricted to the cytoplasm invade the nucleus (outline shown in red). In particular, a protein called tubulin (shown in green), which is strictly a cytoplasmic protein, shows up as long filaments that co-opt a large part of the nucleus.

Credit: Courtesy of Dr. Maximiliano D’Angelo, Salk Institute for Biological Studies.

“We still have a very poor understanding of the mechanisms behind cell aging. It has been known for some time that the gene expression profile of an aging cell changes and somehow is linked to age-related diseases, but no one really knows why. Our work could provide an explanation for why we observe age-dependent defects in cells,” says Martin Hetzer, Ph.D., an assistant professor in the Salk’s Molecular and Cell Biology Laboratory. Read More

University of Utah scientists identified a worm gene that is essential for damaged nerve cells to regenerate, and showed they could speed nerve regeneration by over-activating the gene – a step toward new treatments for nerves injured by trauma or disease.

Oddly, the gene and a related “pathway” – a chain of molecular events – is not required for normal nerve development in embryos, the researchers report in the Jan. 22 issue of Science Express, the online edition of the journal Science.

“We discovered a molecular target for a future drug that could vastly improve the ability of a neuron to regenerate after injury,” either from trauma or disease, says biology Professor Michael Bastiani, leader of the research team and a member of the Brain Institute at the University of Utah. Read More

Regional warming and drought stress are the “dominant contributors” to a rapid increase of tree mortality in old growth forests across the West during the past 50 years, a new report concludes, with the Pacific Northwest the hardest hit of all areas studied.

The findings, to be published Friday in the journal Science, suggest that a persistent increase in the mortality rate would ultimately cause a 50 percent reduction in the average tree age in forests, a potential reduction in average tree size and make many forests vulnerable to abrupt dieback. Read More

As parts of us age, even the membrane bound nuclei , which house the genetic instructions for life that are “written” in our DNA, begin to show considerable wear and tear, suggests a new report in the January 23rd issue of the journal Cell, a Cell Press publication. The nuclear pore complexes that normally act as gatekeepers–selectively importing and exporting the molecular ingredients for life to and from the nucleus–begin to break down and spring leaks.

That’s because some of the 30 or so nucleoporin proteins that make up those complexes can’t be replaced once cells stop dividing, they found. Read More

Tree death rates have more than doubled over the last few decades in old-growth forests of the western United States, and the most probable cause of the worrisome trend is regional warming, according to a U.S. Geological Survey-led (USGS) study published in Science on January 23.

The study found that the increase in dying trees has been pervasive. Tree death rates have increased across a wide variety of forest types, at all elevations, in trees of all sizes, and in pines, firs, hemlocks, and other kinds of trees. Read More