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(Bio) Nectar and Pollination, Nectar: The First Soft Drink

 
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PostPosted: Sat May 13, 2006 7:53 am    Post subject: (Bio) Nectar and Pollination, Nectar: The First Soft Drink Reply with quote






Nectar: The First Soft Drink
Food coloring, preservatives, and all


Susan Milius
13 May 2006
http://sciencenews.org/articles/20060513/bob10.asp

Pressurized fizz and industrial processing aside, modern soft drink makers lag millions of years behind the curve, still catching up with the original purveyors of tasty, sugary beverages. Flowering plants have spent aeons competing with each other to coax animals to choose their formulation of something sweet. While sweetness is important, any devoted fan of a particular brand of soft drink will tell you that a truly alluring elixir has so much more.

Botanists once spoke of nectar as basically sugar water, but in the 1970s, when two researchers checked hundreds of flower nectars, plenty of other ingredients turned up, including amino acids and alkaloids. Researchers are still exploring these and other nectar ingredients. They're also determining the compounds' market appeal.

While a successful recipe brings financial profit to beverage companies, nectars attract animals that provide a service to the plant. Usually it's the transport of pollen from flower to flower, but some plants drip nectar from their leaves or stems to attract insects that protect them from pests.

Most kinds of additives dreamed up by today's drink manufacturers have, with recent research, been recognized in plant nectars. Coloring to beguile the eye? Scents to interest the nose? Health boosters? Preservatives? Some plants have mixed each of these into nectar concoctions.


Rainbow appeal
Even before a pollinator tastes nectar, the seduction begins. For example, although most nectars are colorless, some plants use bright colors to advertise their liquid appeal. Other nectars give off specific aromas.

The question of food coloring in nectars—all natural, that is—has gained scientific attention thanks to a gardener in the greenhouses at Århus University in Denmark. In the early 1990s, the gardener told ecologist Jens Olesen that one of the rare flowers, the blue-purple bellflower called Nesocodon mauritianus, had blood-red nectar. As Dennis Hansen, an Århus student at the time, summarizes events, "Jens said, 'Bollocks! You're drunk! Nectars don't have colors!' And they went to look, and the nectar was red."

Danish research teams then visited the island nation of Mauritius, east of Africa, and spent days watching the cliff-face home of the last 130-or-so known plants of the species. The observers had hoped to spot a native pollinator, especially one with a preference for red nectar, but they failed.

However, while traveling in Mauritius, they had identified two other species—of the genus Trochetia, in another botanical family—that produce colored nectar. The researchers believed these were the only three species in the world with colorful nectar, notes Hansen, who's now at the University of Zurich. "In scientific papers, you always have to say, 'To the best of our knowledge ...'," he says. "Since then, our knowledge has been bettered."

After reading the article, people wrote to the Danish researchers from around the globe pointing out overlooked flowers with colored nectar. When the tally reached 11 species, Hansen decided to write an update.

To make sure that his list was complete, he and several collaborators chased down obscure journals that don't show up in databases and spent hours searching on the Internet for the phrase colored nectar translated into many languages. This ploy led him to Swedish chats about a hoya species grown as a houseplant. Its dark nectar drips on furniture, and people were offering tips about coping with dribbles. "Some of my best pictures [of colored nectar] came from Swedish housewives," Hansen says.

By this March, the tally had topped 60 species making, for example, red, yellow, or black nectars. These plants are scattered in 14 families and located around the world.

There are now four known populations of the rare Nesocodon bellflower plus Trochetia patches. Some of these plants live among potential pollinators: geckos with a taste for nectar.

To see whether geckos prefer colored nectar, Hansen and his colleagues worked on a Mauritian islet inhabited by a gecko species found on the cliff faces. The researchers could test the geckos' innate preference because the colored-nectar plants typically don't grow on the islet and so the animals hadn't been exposed to them.

The researchers made artificial flowers by sticking cardboard petals on painted laboratory tubes and filling them with various sugar solutions. Within half an hour of setting out a pair of fake flowers, the researchers typically saw a gecko skitter over to check out the contraptions.

The animals usually paused to look at the baits for several minutes and then darted to drink at one. More than two-thirds of the geckos chose a flower with colored nectar, tinted red or yellow with food coloring, instead of its nearby twin with colorless nectar.

The bright liquids inside the white tubes seemed innately appealing to the lizards, Hansen and his colleagues report in an upcoming Biology Letters.

Like colors, nectar scents may provide another come-on to pollinators. Under some circumstances, a plant might benefit from letting its pollinators tell by just a sniff whether a flower brims with nectar or has already been emptied, Robert Raguso at the University of South Carolina in Columbia proposed in 2004.

For example, nectar of an evening primrose, Oenothera primiveris, smells sharp and pungent, he says. He found methyl benzoate, as well as another volatile chemical, wafting away from the nectar. Yet his tests didn't pick up either of the scents in petals or other flower parts. Since then, he and his colleagues have identified a second unique component, 1-pyrroline. "It has a most unpleasant odor reminiscent of bleach," says Raguso.

The nectar of the century plant, Agave palmeri, smells like an overripe melon, he says. Seven of the 17 volatile compounds he found in it didn't occur in the flower tissues around it. Some of these special nectar compounds, such as short-chain alcohols and ketones, could be fermentation products, he says. Since his 2004 report, Raguso has found signs of fermentation in the nectar of a flower in the genus Protea. When fresh, it smells like papaya but later develops the odor of honey beer. Plants and their microbial lodgers may have beaten humanity to the invention of brewing too.


Healthy drinks
Biologists are intrigued by the possibility that plants also invented health-and-energy drinks for pollinators, not to mention agents that keep the beverage fresh.

In 2002, Robert Barclay of the University of Calgary in Alberta reported the calcium content of 22 species of Australian flowers. He proposed that flowers visited by nectar-and-fruit–feeding bats tended to offer a bit of extra calcium as a potential boon for lactating females.

More recently, Robert Thornburg of Iowa State University in Ames and his colleagues have suggested that ornamental tobacco offers its insect visitors an energy drink.

From the plant's nectar, Thornburg identified 11 of the 20 amino acids that living organisms commonly hitch together to form proteins. One, proline, appeared in high concentrations, at almost triple the concentration of the next-most-abundant amino acid. Two wild plants, soybean species from Australia, likewise showed abundant proline in nectar.

Earlier studies had indicated that insects' flight muscles burn a lot of proline during the initial phases of flight. It's a better short-term energy source than glucose, Thornburg says, because it doesn't need as much of a jolt of energy to start its breakdown.

Thornburg performed experiments using bees, which pollinate many types of plants, including soy. Previous work had shown that a bee's taste receptors for salts respond to proline. When Thornburg offered honeybees sugar solutions flavored with proline, the one they preferred had a proline concentration similar to that of the tobacco and soy nectars.

Honeybees may have a taste for performance drinks, Thornburg and his colleagues propose in an upcoming Naturwissenschaften.

That's a preference that farmers could turn to their advantage, says Thornburg. If researchers could figure out how to boost the proline content of nectars in crop plants, he says, perhaps more insects would visit. Those additional visits could increase pollination, which would raise the number and the size of fruits.

Letting nutritious brews such as nectars sit around in unrefrigerated blossoms could have disgusting consequences, especially with pollinators tracking who-knows-what into a flower. "They can be in the barnyard this morning and, in the afternoon, get into a plant's reproductive tract," says Thornburg.

In the early 1990s, a chance remark from a colleague started Thornburg thinking about protein in nectar. "I had never considered that nectar was anything but a simple sugar water," he recalls. "Boy, was I wrong."

That afternoon, Thornburg ran a lab test that indicates proteins as blots on a gel strip. "Lo and behold, there were proteins," he says. "I still have the gel on my desk."

He was on sabbatical at the time his lab finished identifying the first of the five proteins. As soon as he got the e-mail with the results, he says, he plunged into databases to find similar compounds. Those chemical cousins produce bursts of hydrogen peroxide in cells, and his colleagues back in the lab soon determined that the nectar protein could do that too.

The hydrogen peroxide produced in cells is the same chemical that drugstores sell to disinfect kids' skinned knees. However, working out the functions of the five nectar proteins took Thornburg and his colleagues 11 years.

In the November 2005 Plant Physiology, the research team described the workings of the most elusive of the five proteins that create a floral-hygiene system. The infection-fighting hydrogen peroxide spins off highly reactive free radicals that can wipe out necessary cell chemistry. Fortunately, some of the five proteins detoxify the free radicals.

Plants may have pioneered another soft drink ploy—adding stimulants. Caffeine and nicotine show up in plant nectars, and Natarajan Singaravelan of the University of Haifa at Oranim in Israel and his colleagues are testing the hypothesis that such extras might keep pollinators coming back for more.

Some citrus nectars, for example, carry a jolt of caffeine. Although science can't yet say whether caffeine gives bees a buzz, they seem to like it. When the researchers offered free-flying honeybees a variety of caffeine-containing sugar solutions plus a caffeine-free version, the bees preferred a mildly caffeinated option. They made about 20 percent more visits to this spiked solution than to the plain-sugar one, the researchers reported in the December 2005 Journal of Chemical Ecology.

Sugary sips with just a touch of nicotine, either 0.5 or 1 parts per million (ppm), attracted more bees than plain-sugar solution did, the researches said in the same paper. The nectar of some tobacco species as well as that of linden trees carries between 0.1 and 5 ppm nicotine. Caged bees and their broods fed sugar solutions with dashes of nicotine showed no obvious ill effects, the researchers reported in the January Journal of Chemical Ecology.


Production problems
There's still toxic stuff in some nectar, though. The 1970s surveys by Herbert Baker and Irene Baker, both since deceased, turned up alkaloids, a group of compounds that includes plant–chemical warfare agents, in 9 percent of the species' nectars. Another worrisome set of compounds—amino acids that organisms don't routinely use in proteins and that can sabotage natural processes—appeared in about half of the nectars.

For years, biologists dreamed up potential advantages for nectars that are harmful to some animals, says Lynn Adler of the University of Massachusetts in Amherst. For example, theorists proposed that a nectar repellent to many creatures might result in fewer visits from sloppy, go-everywhere pollinators that would waste a plant's pollen on other species.

Then there was the "drunken-pollinator" hypothesis. Some nectars include ethanol or other intoxicants, and bees act oddly after imbibing. So, the theory goes, pollinators that drink spiked nectar get lackadaisical about grooming and careen around in a disheveled state delivering unusually large amounts of pollen.

In the November 2005 Ecology, Adler and Rebecca Irwin of Dartmouth College in Hanover, N.H., published what Adler suspects is the first test of whether toxic nectars aid plant reproduction. They used Carolina jessamine (Gelsemium sempervirens), a vine that bursts out in yellow flowers during March and April in its southeastern–U.S. range. Its nectar carries the toxin gelsemine, a substance also found in leaves that botanists suspect keep pests from chewing there.

In experimental plots of the vine, researchers made the rounds every morning during blooming season, carefully pipetting droplets into each open flower. Some flowers got extra doses of gelsemine, while others got a sugar solution that diluted their natural nectar's gelsemine concentration. To estimate how much pollen the insects moved, the researchers dusted flowers with fluorescent dye as a proxy for pollen.

Researchers then hovered around the plot clutching tape recorders to dictate running accounts of insect visits, which exceeded 3,000 by the end of the experiment.

"Ultimately, we found that pollinators really don't like toxic nectar," says Adler. Compared with diluted gelsemine, extra gelsemine cut short insects' visits to a particular flower and reduced the number of flowers visited. At each stop, the pollinators passed along only half to two-thirds as much pollen from the high-gelsemine plant as from low-toxin plants.

No advantage of extra gelsemine showed up. Carpenter bees still drilled holes in the flowers and drained nectar without carrying pollen to other plants. "So far, we're seeing mostly costs," says Adler.

She says that she's begun questioning whether toxic nectars do any good for plants. The toxic compounds that show up in nectar also appear in plant leaves, where they seem to discourage grazing by mammals and insects. The compounds could simply be leaking out of the plant into the nectary.

If defensive chemicals turn up in nectar but provide no benefit there, then plants could win yet another distinction. They could have been the first food manufacturers to face the problem of pesticide contamination.

*************************************************************

Questions to explore further this topic:

A Lesson Plan on plants

http://www.apsnet.org/educatio.....onplan.htm

Flowers

http://www.cnps.org/programs/education/pollin.htm
http://is.asu.edu/plb108/cours...../ftoc.html
http://www.offwell.free-online.co.uk/flower.htm
http://www.bbc.co.uk/scotland/.....rev3.shtml
http://www.conservatoryofflowe.....densed.htm
http://web.pdx.edu/~cruzan/Flo.....opment.pdf

Flower form and function

http://www.hcs.ohio-state.edu/hcs300/angio3.htm

Plants and Animals: Partners in Pollination

http://www.smithsonianeducatio.....index.html

Plant and animal interactions

http://www.mobot.org/education/tropics/page5.html
http://www.rhs.org.uk/research.....ldlife.asp

Pollination adaptations

http://koning.ecsu.ctstateu.ed.....adapt.html

Pollination movies

http://hemingwaysouthcarolina......leries.htm

Plant parents

http://www.sciencenetlinks.com.....m?DocID=91

Plant propagation

http://www.sciencenetlinks.com.....m?DocID=22

The story of pollination

http://www.nhb.org/download/ed.....ochure.pdf

A simulated pollination exercise

http://www.zoo.utoronto.ca/abl.....illing.pdf

A Lesson on pollination

http://school.discovery.com/le.....llination/
http://school.discovery.com/le.....tterflies/

Flowers and perfumes

http://www.mhhe.com/biosci/pae.....le_07.html

What is nectar?

http://www.bb.iastate.edu/necgex/Nectar.htm
http://www.bbg.org/gar2/topics.....ectar.html

Chemical composition of nectar

http://aob.oxfordjournals.org/.....l/94/2/269
http://www.bb.iastate.edu/~tho.....earch.html

A database of plants that produce nectar

http://www.foremostbutterflies.....plants.htm
http://www.pfaf.org/database/s.....%5D=Nectar
http://www.pineridgegardens.com/nectar.htm

How is honey produced from nectar?

http://www.draperbee.com/info/honey.htm
http://www.capilano.com.au/edu.....honey.html

Proteins in nectar

http://www.bb.iastate.edu/necg.....oteins.htm

Amino acids in nectar

http://www.biol.vt.edu/Researc.....202005.pdf

Narcotic compounds from nectar

http://www.ecology.kee.hu/pdf/0302_029038.pdf

How does a bee locate the position where nectar is?

http://www.cals.ncsu.edu/cours.....guide.html
http://www.pbs.org/wgbh/nova/bees/danceslang.html

Nectar and bees

http://www.clover.okstate.edu/.....esmart.pdf

Nectar and migratory pollinators

http://www.conbio.org/cip/article21nec.cfm
http://www.desertmuseum.org/po.....ation.html

Nectar and hummingbirds

http://www.stanford.edu/group/.....ectar.html

Nectar and bats

http://news.nationalgeographic.....uvbat.html
http://www.lubee.org/aboutbats.aspx

Nectar in cactus and ants in the desert

http://www.ruf.rice.edu/~bws/index.html

Nectar and butterflies

http://www.enature.com/article.....toryID=631
http://www.clemson.edu/hort/sctop/dsec/dsec-04.php

Count monarchs at a nectar source: A math activity

http://www.learner.org/jnorth/.....ectar.html

Nectar biology: An experiment

http://web.cortland.edu/broyle.....ology.html

GAMES

http://www.honey.com/kids/games.html


Last edited by adedios on Sat Jan 27, 2007 3:42 pm; edited 2 times in total
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PostPosted: Thu Oct 26, 2006 7:00 am    Post subject: Pollinators help one-third of world's crop production, says Reply with quote

Pollinators help one-third of world's crop production, says new study

By Sarah Yang, Media Relations | 25 October 2006

BERKELEY – Pollinators such as bees, birds and bats affect 35 percent of the world's crop production, increasing the output of 87 of the leading food crops worldwide, finds a new study published today (Wednesday, Oct. 25), in the Proceedings of the Royal Society B: Biological Sciences and co-authored by a conservation biologist at the University of California, Berkeley.

The study is the first global estimate of crop production that is reliant upon animal pollination. It comes one week after a National Research Council (NRC) report detailed the troubling decline in populations of key North American pollinators, which help spread the pollen needed for fertilization of such crops as fruits, vegetables, nuts, spices and oilseed.

For the full article:

http://www.berkeley.edu/news/m.....ator.shtml
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PostPosted: Wed Feb 28, 2007 8:27 am    Post subject: Nectar is not a simple soft drink Reply with quote

Blackwell Publishing Ltd.
27 February 2007

Nectar is not a simple soft drink

The sugar-containing nectar secreted by plants and consumed by pollinators shares a number of similarities to fitness drinks, including ingredients such as amino acids and vitamins. In addition to these components, nectar can also contain secondary metabolites such as the alkaloid nicotine and other toxic compounds. Scientists Danny Kessler and Ian Baldwin from the Max Planck Institute for Chemical Ecology in Jena, Germany, recently addressed the question, why would plants risk poisoning the insects and birds that provide pollination services? Their findings have been published in The Plant Journal.

Kessler and Baldwin examined the nectar of a wild tobacco species, Nicotiana attenuata, and discovered that it is flavoured with 35 secondary compounds. The researchers then tested 16 of these in cafeteria-style bioassays with three groups of native visitors - hawkmoths, hummingbirds (both pollinators) and ants ('nectar thieves'). Some compounds were attractive and others were not. Certain nectar blends seem to increase a flower's chances of being visited by useful pollinators while discouraging nectar thieves.

Nicotine, the most abundant repellent found, affected both pollinators and nectar thieves in the same way. The visitors removed less nectar per visit when nicotine was present. To determine if nicotine was repellent in the real world, the researchers genetically transformed N. attenuata plants to create nicotine-free plants, which were planted into a natural population and nectar removal rates were measured. Native floral visitors removed much more nectar from the plants that had no nicotine than from the normal nicotine-containing plants. Why would a plant produce nectar that repels pollinators? Data from the bioassays provided a hypothesis: when nectar contains nicotine, the amount of nectar consumed per visit decreases but the number of visitations increases. Increasing the number of visitors might increase the genetic diversity of the offspring produced. The researchers are planning to test this hypothesis in the upcoming field season.

Dissecting the function of this secret formula of nectar, thought to be nature's soft drink, has instead shown it to be quite 'hard'.
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PostPosted: Tue Apr 17, 2007 7:40 am    Post subject: The cost of long tongues Reply with quote

University of Chicago Press Journals
16 April 2007

The cost of long tongues
Orchid bees with long tongues get nectar more slowly

Orchid bees use their extraordinarily long tongues to drink nectar from the deep, tropical flowers only they can access. Researchers have long suspected that this kind of exclusive access came with a mechanical cost. According to common sense and a classic law of fluid mechanics, it's just plain hard to suck thick, viscous nectars up through a long straw. Now, Brendan Borrell at the University of California, Berkeley has confirmed this prediction for the first time: orchid bees with long tongues suck up their nectars more slowly than bees with shorter tongues.

Borrell spent three years collecting bees in forests all over Costa Rica and Panama and measuring their feeding rates at artificial flowers. He found that the smallest bees sometimes had the longest tongues and the largest bees sometimes had the shortest tongues. But after taking into account all that variation in body size, he says long tongues really do impose a mechanical cost on bees. Everyone knows just how busy bees can be, but orchid bees are basically sacrificing speed at flowers for exclusive access to them. Borrell thinks this may be because the rewards at these flowers can be tremendous, up to ten times the quanity of nectar provided by typical bee flowers.

###
Brendan J. Borrell, "Scaling of nectar foraging in orchid bees" American Naturalist, 2007, 169: 569–580. DOI: 10.1086/512689

Founded in 1867, The American Naturalist is one of the world's most renowned, peer-reviewed publications in ecology, evolution, and population and integrative biology research. AN emphasizes sophisticated methodologies and innovative theoretical syntheses—all in an effort to advance the knowledge of organic evolution and other broad biological principles.
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PostPosted: Fri Jun 08, 2007 9:40 am    Post subject: Columbine flowers develop long nectar spurs in response to p Reply with quote

National Science Foundation
7 June 2007

Columbine flowers develop long nectar spurs in response to pollinators

Research offers evidence that evolution may occur in a stop-and-go pattern
In flowers called columbines, evolution of the length of nectar spurs--the long tubes leading to plants' nectar--happens in a way that allows flowers to match the tongue lengths of the pollinators that drink their nectar, biologists have found.

The researchers were Justen Whittall of the University of California at Davis and Scott Hodges of the University of California at Santa Barbara. They were funded by the National Science Foundation (NSF). Their results appear in this week's issue of the journal Nature.

Darwin once proposed a co-evolutionary "race" to explain how natural selection might account for the evolution of very long nectar spurs in flowers, said Hodges. "In Darwin's race, plants with the longest spurs and pollinators with the longest tongues [to tap the flowers' nectar] would be favored by natural selection, and--in a never-ending process--continually drive the plants' spurs and the pollinator tongues to exceptionally long lengths."

But it turns out, Whittall and Hodges found, that evolution acts in a more one-sided fashion in many plants: the plants evolve nectar spurs to match the tongue-lengths of the pollinators. Then the process stops, and only starts again when there is a change in pollinators.

Whittall and Hodges proved this idea by testing the columbine genus Aquilegia, which is pollinated by bumblebees, hummingbirds and hawkmoths.

They found that most of the columbines' nectar spur length evolution happened during shifts in pollinators from bumblebees to hummingbirds, and from hummingbirds to hawkmoths. In between these shifts, evolution of the columbines' nectar spurs came to a halt.

Whittall and Hodges' work provides evidence that evolution may occur in a stop-and-go pattern--one in which adaptation to specific pollinators occurs very rapidly, followed by periods of no further evolution until another pollinator shift occurs, according to William Zamer, deputy director of NSF's division of integrative organismal systems.

"In the case of these flowers, changes appear to happen relatively rapidly in response to changes in pollinators," said Zamer.

###
NSF's biocomplexity in the environment emphasis area and division of environmental biology funded the research.

NSF-PR 07-065

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of $5.58 billion. NSF funds reach all 50 states through grants to nearly 1,700 universities and institutions. Each year, NSF receives about 40,000 competitive requests for funding, and makes nearly 10,000 new funding awards. The NSF also awards over $400 million in professional and service contracts yearly.

Receive official NSF news electronically through the e-mail delivery and notification system, MyNSF (formerly the Custom News Service). To subscribe, visit http://www.nsf.gov/mynsf/ and fill in the information under "new users".

Useful NSF Web Sites:
NSF Home Page: http://www.nsf.gov
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PostPosted: Mon Jul 09, 2007 8:11 am    Post subject: Size and positioning of floral anthers facilitates pollen co Reply with quote

American Society of Plant Biologists
9 July 2007

Size and positioning of floral anthers facilitates pollen collection by bees

Decoding the evolution of flowers -- From genomes to petals
Unlike moths and butterflies that are often brilliantly colored to warn potential predators that they carry toxins, flowers and the fruits they produce have brilliant colors and unusual shapes because they want to attract the attention of pollinators and frugivores who will disperse their pollen and seed, thus guaranteeing the next generation. In their work, Dr. Endress and his colleagues found that the sizes and positioning of the anthers facilitates pollen collection by buzz-pollinating bees. The male floral structures, anthers, release the pollen gradually, like tiny gumball dispensers. All of these characteristics--size, shape, placement, and timing—may be controlled by networks of genes as well as by regulatory sequences that do not encode proteins. Slight changes in these networks or in the non-coding sequences can change the developmental pattern of a flower and thus its morphology—either dooming it if its pollinators can no longer “fit” properly or guaranteeing the success of the species if it acquires new pollinators. This type of information is becoming ever more critical as we struggle to understand, maintain, and modify the plant and pollinator systems that we depend on for life.

Evo-Devo, or the linking of evolution and development is a shift in the paradigm of how organisms evolved and diversified. In a symposium at the joint annual meeting of the American Society of Plant Biologists and the Botanical Society of America (July 7-11), Dr. Peter Endress of the Institute of Systematic Botany at the University of Zurich will present his work on the functional architecture of flowers and the role of development in floral evolution.

Charles Darwin, who observed closely the productions of breeders of pigeons, dogs, and flowers, understood that explaining the evolution and diversity of living organisms, from mosses to elephants, would require an understanding of development. In his presentation at a joint ASPB and BSA symposium on evolutionary development at the annual meeting in Chicago (July 9, 2007, 2PM) Dr. Peter Endress will address the need to compare developmental patterns across many taxa of flowering plants to gain insight into flower evolution. In a study reported in the International Journal of Plant Science, Dr. Endress and his coauthors Brigitte Marazzi and Elena Conti, compared floral structures across numerous species of the genus Senna in the pea family. These flowers are specialized to be pollinated by bees that release the pollen through vibrations caused by their buzzing. Endress and his coworkers found a diversity of floral structures that may represent different strategies for pollen dispersal, even in the same genus.

The appearance of flowering plants on earth about 150 million years ago had a profound effect on the evolution of many other kinds of organisms like insects, birds, and mammals, who became the pollinators and consumers of those plants, thus ensuring the continuity of both the plant and its animal partner. Scientists are beginning to understand just how intimate and important these interactions are, as both plants and pollinators are threatened by extinction due to habitat loss and pollution from human activities. The recent alarm over the collapse of honeybee colonies has underscored the importance of insect pollinators not only to crops consumed by humans but also to plants that support the ecosystems we depend on.

Flower architecture has great evolutionary and economic importance. Minute differences in the size and placement of the male and female reproductive parts of a flower can determine how those flowers are pollinated--by insects, birds, animals, wind, or the flowers themselves. Genetic programs determine how the embryos will grow, when the fruit opens to disperse the seed, how the fruit is positioned to attract potential dispersers or when it falls to the ground. The method and timing of pollen dispersal from a plant can determine whether or not a plant modified to resist an insect pest will also have an effect on other more beneficial insects. Scientists are racing to understand these minute differences and interactions, even as habitat loss and climate change threaten the existence of many plants as well as their pollinators. The Floral Genome Project is a consortium of labs in the United States and abroad whose goal is to construct a database that will contain comparative data on the expression patterns for a large number of genes across many different families of flowering plants.

Starting with Linnaeus, plants and animals were formally classified on the basis of their physical characteristics—their morphology. With the revolution in DNA sequencing, or genomics, plants and animals are also classified on the basis of their gene sequences. These two areas of systematics often produced conflicting results, but as more genomes are sequenced and the functions of numerous genes studied, both zoologists and plant biologists have begun to understand that gene sequences alone cannot explain diversity. Within the last few years, scientists have begun to identify groups of genes, called networks, which control complex programs that determine an organism’s final form. In addition, the parts of the genome that do not code for proteins, the non-coding regions, are assuming greater importance in explaining the diversity found in different species of plants and animals.

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The article cited in this release was published in 2007 in The International Journal of Plant Science, Vol 168, Issue 4, pp. 371-391.
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PostPosted: Tue Jul 31, 2007 11:27 am    Post subject: Measuring nectar from eucalypts Reply with quote

Measuring nectar from eucalypts
New South Wales DPI
26 Jul 2007

Using cranes and cherry-pickers, nectar from flowers in forest canopies over 30 metres high was bagged overnight and measured by NSW DPI researchers. The effect of logging on canopy nectar production in tall forest trees has for the first time been investigated by NSW DPI researchers, with funding from the Honeybee Program of the Rural Industries Research and Development Corporation and Forests NSW.

State forests provide the major honey resource for the beekeeping industry in NSW.

While Forests NSW has a number of management practices in place to retain nectar-producing trees during logging operations, there has been no information on how much nectar is produced by retained trees or young trees regrowing after logging.

Indeed, beekeepers have expressed concern about the effects of logging on nectar production, especially the perception that young trees do not produce as much nectar as mature trees.

The two eucalypt species chosen for research, Spotted Gum Corymbia maculata and Grey Ironbark Eucalyptus paniculata, are of prime importance to nectarfeeding wildlife, the timber industry and beekeepers.

Using cranes and cherry-pickers, flowers in forest canopies over 30 metres high on the NSW south coast were accessed. Nectar in flowers bagged overnight was measured to determine how much nectar they produce.

Both large and small trees were measured in forest with different logging histories: recently logged, regrowth and mature (more than 50 years since logging).

After measuring thousands of flowers, the study concluded that nectar production in Spotted Gum on a per flower basis was not affected by logging history nor tree size.

When the amount of nectar produced by whole forest stands is estimated on the basis of individual flower measurements and counts of flowers and trees, the study found that mature forest produced almost 10 times as much sugar per hectare as recently logged forest.

However, because current logging practices result in a mosaic landscape, where some areas are logged and others are left untouched, the impact is far less.

An estimate of nectar production at a ‘compartment’ scale found a recently logged compartment produced half the amount of nectar as a compartment of mature forest.

Most importantly, nectar was not a limited resource in 2005, when the research was undertaken, as extensive flowering was recorded across the south coast.

The study surveyed local beekeepers with questionnaires and found that honey yields in 2005 were extremely high: a typical 1000 hectares of spotted gum forest flowering from April-August yielded five tonnes of honey.

Honey productivity was found to be comparable across the three different logging histories: recently logged, regrowth and mature. But not every year is as good as 2005, with flowers measured in 2003 providing a strong contrast.

Few trees were in flower and nectarivores, especially birds and honeybees, left virtually no nectar behind by mid-morning.

Beekeepers reported that hive bees were not producing honey under these conditions.

Results for grey ironbark showed similarities to spotted gum with regard to the impact of logging, but the species differed markedly in other aspects of nectar production.

The results of this study will help promote sustainability by raising the awareness of forestry organisations about the importance of the nectar resource for native fauna and honeybees and that of beekeepers about current forest management.
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PostPosted: Thu Oct 04, 2007 1:24 pm    Post subject: Living fossils have hot sex Reply with quote

University of Utah
4 October 2007

Living fossils have hot sex

Primitive plants use heat and odor to woo pollinating insects

University of Utah scientists discovered a strange method of reproduction in primitive plants named cycads: The plants heat up and emit a toxic odor to drive pollen-covered insects out of male cycad cones, and then use a milder odor to draw the bugs into female cones so the plants are pollinated.

For the full article:

http://www.unews.utah.edu/p/?r=092507-3
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PostPosted: Tue May 13, 2008 2:24 pm    Post subject: Fast-fading fragrance Reply with quote

Fast-fading fragrance
By Jennifer Cutraro
May 12th, 2008

Take time to stop and smell the flowers, goes a familiar saying. But that might be harder to do today than it used to be. Scientists recently reported that air pollution quickly destroys some of the sweet-smelling perfumes flowers produce. It's a problem that could have long-lasting effects on plant reproduction and diversity, and might help explain why populations of bees and other pollinators are declining.

For the full article:

http://sciencenews.org/view/ge....._fragrance
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