January 28, 2010, 8:07 AM CT

Figs and fig wasps

Figs and fig wasps have evolved to help each other out: Fig wasps lay their eggs inside the fruit where the wasp larvae can safely develop, and in return, the wasps pollinate the figs.

But what happens when a wasp lays its eggs but fails to pollinate the fig?

The trees get even by dropping those figs to the ground, killing the baby wasps inside, reports a Cornell University and Smithsonian Tropical Research Institute study reported in the Proceedings of the Royal Society B (published online Jan. 13).

The findings suggest that when one species in a mutually beneficial relationship fails to hold up its end of the bargain, sanctions appears to be a necessary part of maintaining the relationship.

"We want to know what forces maintain this 80 million-year-old mutualism between figs and their wasp pollinators," said main author Charlotte Jandr, a Cornell graduate student in neurobiology and behavior, who conducted the study as a Smithsonian Tropical Research Institute predoctoral fellow. Edward Allen Herre, a staff scientist at the Smithsonian institute in Panama, co-authored the paper.

"What prevents the wasps from cheating and reaping the benefits of the relationship without paying the costs?" Jandr added.

More than 700 species each of fig trees and wasps have co-evolved in the tropics worldwide, with each fig tree species having its own species of pollinating wasp. Jandr worked on six fig tree-fig wasp pairs for the study. Some wasp species passively carry pollen that sticks to their bodies, while others actively collect pollen in special pouches......... Posted by: Kelly      Read more         Source

Mon, 25 Jan 2010 00:58:48 GMT

Guaiacum sanctum

Today"s photograph is shared by Peter Buchwald (original image | Creative Commons License). Lindsay continues with January"s thematic series on conservation of rare plants as part of the International Year of Biodiversity. Lindsay writes:

Commonly known as lignum vitae ("wood of life") or holywood, Guaiacum sanctum is native to the Florida Keys of the southeast USA, Central America and the Caribbean. It is the national flower of the Jamaica. Lignum vitae is an extremely slow-growing, multi-trunked, broadleaf evergreen which can reach 9m to 12m, but because of its slow growth and heavy harvesting, it is more commonly found at 2.5m to 3.5m tall in the wild.

A number of times each year, the leathery, dark green leaves are offset by large clusters of deep blue flowers. The old flowers fade to a light silvery-blue, and create a "shimmering halo" over the rounded canopy. Flowers are followed by small, heart-shaped, yellow fruits, which sometimes appear at the same time as the blue flowers--a stunning sight. The wood of this genus is famous for its density, durability and strength. It is the hardest trade wood measured via the Janka hardness test and will sink in water. This dense wood was once popular for use in propeller shafts on steamships, gears and mallets.Lignum vitae was also harvested, somewhat notoriously, for medicinal purposes. Purportedly, during his travels in the New World, Christopher Columbus picked up both syphilis and its cure--a concoction of lignum vitae!

All species of the genus Guaiacum are now listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora. According to the World Conservation Monitoring Centre, Guaiacum sanctum is considered endangered. It is similarly listed on the International Union for Conservation of Nature"s Red List of Threatened Species. Population estimates suggest less than 2500 mature specimens in the wild, and those remaining individuals still face a rapid decline. Decline is principally due to deforestation and exploitation for human uses. In Central America and Florida remaining populations are threatened with habitat loss or exploitation, e.g., in Guancaste in Costa Rica, El Salvador, and Florida Keys. Conservation groups in both Costa Rica and the Bahamas have been successful in lobbying local authorities to ban sale and export of lignum vitae by establishing protected areas in its natural range. Despite its slow growth rate, propagation of Guaiacum sanctumis fairly easy. Current research suggests its use in rehabilitating degraded sites within its natural range. Posted by: Daniel Mosquin      Read more     Source

Sun, 24 Jan 2010 10:05:32 GMT

Just another day in the woods

Hard for me to believe that we went 17 days into the new year — the new decade! — without going to Roundrock. Circumstances got in the way, but yesterday I decided I wasn’t going to delay my return to the woods any longer, so we jumped into the truck (pups included) and drove through the thick, thick fog to our forest.

Except for the road in (and then out) we had a wonderful time. The ground is frozen except on the surface. Thus all of the melted snow and ice is not being absorbed. What doesn’t find a way to run off (which is a problem since lingering ice dams are blocking some normal run-off routes) just sits on the surface. Add a few days with temps above freezing, and add the apparent fact that the whole county seems to want to visit my cabin when I’m not there, and you have a horrible gumbo of a road across the meadow and along my northern property line. It was nothing but sluices and sliding and slinging of mud. But the nimble Prolechariot made it through, and we parked by the cabin feeling like victors.

Flike had been out to the woods on our last trip, but that was with the whole family, so there was plenty of supervision. On yesterday’s trip, it was just Libby and I to make sure he didn’t get eaten by a bear or something.

But the goal is the have a companion to join us on our forest romps, so we let him off his leash to see how he would behave. He was perfect. Of course he was excited to have so much open ground for his long legs to course across, and there are all of those wonderful smells in the forest, and good things to eat (ugh!), and the full measure of puppyhood still in his 40+ pounds, so he was bounding from here to there to the other place constantly. Whenever we called him back, though, he came running. Good dog!

Queequeg, on the other hand, is not so obedient. Sure, he wants to do everything Flike does, but when he strays too far from us, we’re certain a lurking bobcat or coyote is ready to snatch him. Nor does he come when called, unless there’s something in it for him, like a treat. So Queequeg spent the day on the end of his leash, which can be cumbersome for both dog and master in the dense undergrowth and frequent windfall of an Ozark forest. Plus though his spirit is roaring, his little legs just don’t have the stamina that Flike’s do, so he got carried a bit on our walks.

We got a few important chores done, which I’ll tell you about in the coming days, but the biggest news is that Flike is proving himself to be a perfect Roundrock companion.

Missouri calendar:

• Martin Luther King Jr. Day (observed)

Posted by: Roundrockjournal      Read more     Source

January 22, 2010, 8:17 AM CT

Withstanding invasion

An international research team has studied the distribution of plant species in mountainous environments. The study shows that mountain plant communities are not especially resistant to invasion by exotic species. The researchers also warn that these appears to become more aggressive as global warming gets a grip.

In 2005, researchers from various science centres in Spain, Gera number of, Switzerland, Australia, the United States and Chile created the Mountain Invasion Research Unit (MIREN) in order to study the distribution of exotic species in high mountain species and to design experiments to confirm the invasive capacity of certain species in high mountain environments.

"These plant communities in Alpine environments have until now not been thought especially vulnerable to this kind of environmental disturbance", Jos Ramn Arvalo, one of the authors of the study and a researcher at the Department of Ecology of the University of La Laguna, tells SINC. However, the experiments show clearly "that the beliefs about this supposed protection and mountain species' resistance to invasive species is erroneous", he adds.

The study, published recently in Frontiers in Ecology and The Environment, and which is part of the work done by MIREN, has made it possible to identify the factors that make plants in these areas more vulnerable to invasion by other species......... Posted by: Erica      Read more         Source

Mon, 18 Jan 2010 05:40:30 GMT

Pachira aquatica and Pachira glabra

More photographs today from Ian Crown of the Puerto Rican fruit farm, Panoramic Fruit. Thank you Ian!

Also, before getting into today"s entry, welcome readers from the Winston-Salem Journal!

These photographs weren"t all taken in the same place or time, and I believe them to be of two separate species. The first photograph, with the crimson-tipped stamens and yellowish-white strap-like petals is, I think, Pachira aquatica, known commonly as Guiana chestnut or Malabar chestnut. The second and third photographs feature what I"ve tentatively identified as Pachira glabra. In Margaret Barwick"s excellent Tropical and Subtropical Trees: An Encyclopedia, she notes Pachira glabra, or saba nut, to have "light-green, strap-like petals and wiry, white, curving stamens". Hawaiian Tropical Plant Nursery provides brief descriptions of the two species, and also adds: "Much of the material in cultivation as Pachira aquatica is actually Pachira glabra...." Many of the so-called "money trees", it is implied, are therefore Pachira glabra.

Both species are native from Mexico to northern South America. Pachira aquatica grows in coastal estuaries; its seeds are "designed to withstand humidity and are capable of floating in water for months", according to Barwick. Pachira glabra is a species of lowland rainforests and alluvial plains.

Ian Crown wrote the following, but given my notes regarding identification of these two species above, I think parts of this account may be apply to Pachira aquatica, Pachira glabra or both:

"I first encountered Pachira aquatica, the Malabar chestnut, in 1994. I was just starting up an exotic fruit farm in western Puerto Rico and everyone there said I had to meet Milton Perez, the owner of a large garden center in Cabo Rojo, Puerto Rico. I made a point of doing so and ended up with a very dear friend who sadly passed away in 2006 around this time of year."

"Milton had the plant version of a menagerie; so many specimens of different fruits and ornamental plants and lumber species, it boggled the mind. Along a drainage canal, he had a few trees of something new to me but which produced edible, delicious nuts in a football-shaped pod. Milton handed me a few to try. Once the thin woody shell was peeled off, they were crunchy and reminded me of raw peanuts but were a bit larger and bone white. The seeds readily sprouted, grew rapidly, and produced their own flowers and then new seeds within just 2 years. Welcome to the tropics! Those first seeds produced several generations of trees which are now planted in the yards of my crew and many other places. And we still use the trees to reduce erosion where the slope is steep and these trees keeps us in nuts almost year-round. Not for sale, we just give them to locals just the way Milton did years ago."

"One striking feature of this species is that the trunk remains green for many years* and looks like it would be soft. But it withstands hurricanes up to a Category 3 or 4 with little damage, stabilizes the soil, likes very wet spots, tolerates drier sites and is suited to periods of submersion like many Amazon tree species. To add to this roster, it is probably in your nearby supermarket as an almost indestructible bonsai plant. Very hard to drown if given enough light. It is a pretty good house plant and dry air does little to it."

*I"ll add that one of the reasons I think Ian"s account likely includes both species is his description of the trunk. On Pachira glabra, Barwick notes: "It is ornamental, distinguished by....its bright green trunk, limbs and fruit". Posted by: Daniel Mosquin      Read more     Source

January 15, 2010, 8:09 AM CT

Plant-pollinator relationship

Figs and the wasps that pollinate them present one of biologists' favorite examples of a beneficial relationship between two different species. In exchange for the pollination service provided by the wasp, the fig fruit provides room and board for the wasp's developing young. However, wasps do not always pollinate the fig. Fig trees "punish" these "cheaters" by dropping unpollinated fruit, killing the wasp's offspring inside, report scientists working at the Smithsonian Tropical Research Institute.

Their results, reported in the Proceedings of the Royal Society, show that sanctions against cheaters appears to be critical to maintain the relationship.

"Relationships require give and take. We want to know what forces maintain this 80-million-year-old arrangement between figs and their wasp pollinators." said main author, Charlotte Jandr, graduate student in Cornell University's Department of Neurobiology and Behavior, who conducted the study as a Smithsonian pre-doctoral fellow. "What prevents the wasps from reaping the benefits of the relationship without paying the costs?".

Some wasp species passively carry pollen that sticks to their bodies. Others actively collect pollen in special pouches. Jandr reviewed the ability of six different fig tree-fig wasp species pairs to regulate cheating. She introduced either a single pollen-free wasp, or a wasp carrying pollen, into a mesh bag containing an unpollinated fig. The wasps entered the figs to lay their eggs. Jandr observed that trees often dropped unpollinated figs before young wasps could mature......... Posted by: Kelly      Read more         Source

January 15, 2010, 8:04 AM CT

Impact of eucalyptus plantations on the ecology of rivers

A team from the Department of Plant Biology and Ecology at the University of the Basque Country (UPV/EHU) are focusing their research on the study of the ecology of rivers. The person in charge is Mr Jesús Pozo. For more than twenty years this team has been trying to identify links between the ecology and functioning of rivers and the surrounding terrestrial environment because, when all is said and done, rivers are like the excretory apparatus of the continents, just like the kidney is to the human body. River water often reflect the state of health of the external environment.

Within this line of research, the UPV/EHU team is focusing on studying the possible impact of the afforestation of exotic species on the functioning of rivers, both on the chemistry of the water as well as on the communities of organisms therein. An exotic species is a species introduced outside its normal area of distribution, for example, the eucalyptus - the case in hand.

Rivers of any specific geographical environment have a natural riverside type of vegetation and the community of organisms in the river is accustomed to consuming the dead leaves and foliage that enter the water from this surrounding vegetation. When this natural vegetation (in this case deciduous woods) are substituted by exotic plantations the quality of this plant material changes and the community of river organisms have to deal with the use or otherwise of this non-autochthonous organic material. This use or not by the aquatic organisms of the new material entering the river system can have certain repercussions, both on the organisms themselves and on processes occurring in the river......... Posted by: Erica      Read more         Source

January 14, 2010, 8:00 AM CT

Sequencing of soybean genome

Soybean, one of the most important global sources of protein and oil, is now the first major crop legume species with a published complete draft genome sequence. This sequence, which essentially provides a parts list of the soybean genome, will help researchers use the plant's genes to improve its characteristics. The soybean sequencing study appears as the cover story of the January 13 edition of Nature



Value of the new soybean sequence

Researchers will use the new sequence to identify which genes are responsible for particular plant characteristics, and then target specific genes to produce desired characteristics. These desired characteristics may include increases in the plant's oil content to promote the use of soybean oil as a biofuel; bigger crops; improved resistance to pests and diseases that currently claim large percentages of soybean crops; improvements in the digestibility of soybeans by animals and humans; and reductions in contaminants present in the manure of soybean-fed swine and poultry that may pollute farm runoff.

The research team plans to identify which soybean genes warrant targeting by:

• Comparing the genomes of different varieties of soybean plants to one another.
• Resequencing 20,000 soybean lines that are currently stored in the National Plant Germplasm System to identify desired variances of genes that are not currently captured by domesticated soybean lines.

........ Posted by: Erica      Read more         Source

January 11, 2010, 7:53 AM CT

Can a drop of water cause sunburn or fire?

To the gardening world it may have always been considered a fact, but science has never proved the widely held belief that watering your garden in the midday sun can lead to burnt plants. Now a study into sunlit water droplets, published in New Phytologist, provides an answer that not only reverberates across gardens and allotments, but may have implications for forest fires and human sunburn.

"The problem of light focusing by water droplets adhered to plants has never been thoroughly investigated, neither theoretically, nor experimentally", said lead researcher Dr Gabor Horvath, from Hungary's Eotvos University. "However, this is far from a trivial question. The prevailing opinion is that forest fires can be sparked by intense sunlight focused by water drops on dried-out vegetation".

The team conducted both computational and experimental studies to determine how the contact angle between the water droplet and a leaf affects the light environment on a leaf blade. The aim was to clarify the environmental conditions under which sunlit water drops can cause leaf burn.

These experiments observed that water droplets on a smooth surface, such as maple or ginkgo leaves, cannot cause leaf burn. However in contrast the team observed that floating fern leaves, which have small wax hairs, are susceptible to leaf burn. This is because the hairs can hold the water droplets in focus above the leaf's surface, acting as a magnifying glass. The latter not only partly confirms the widely held belief of gardeners, but also opens an analogous issue of sunburn on hairy human skin after bathing......... Posted by: Erica      Read more         Source

January 5, 2010, 8:57 AM CT

Preserving genetic diversity of rice

Rice is one of the most important crops worldwide, as it feeds over half of the world's population. Domesticated rice is an important supply of the world's rice. However, these strains are genetically static and cannot adapt to changing growing conditions. Traditional varieties, or landraces, of rice are genetically evolving and provide a pool of traits that can be tapped to improve crops worldwide.

Research from Barbara A. Schaal, Ph.D., the Mary-Dell Chilton Distinguished Professor of biology in Arts & Sciences at Washington University in St. Louis, and her colleagues at Chiang Mai University in Thailand shows how natural genetic drift and agricultural practices of the traditional farmers combine to influence the genetic diversity of a given landrace of rice.

Schaal is also involved in science policy, serving as vice president of the National Academy of Sciences and recently appointed to the President's Council of Advisors on Science and Technology.

Schaal and her colleagues studied a landrace of rice grown by the Karen people in Thailand. They compared the genetic variation among the same variety of rice grown in different fields and villages. The genetics of the rice population fits the isolation by distance model, much like a native plant species. The further apart fields are, the more genetically distinct they are......... Posted by: Erica      Read more         Source