A New Understanding of the Early Evolution of Flowering Plants

Category(-ies): Plant Discoveries , Plant Relationships

Text courtesy of Dr. Sean Graham:

A research team led by scientists at the UBC Botanical Garden & Centre for Plant Research announce a startling discovery in the March 15, 2007 issue of Nature concerning Hydatellaceae, an obscure family of dwarf, aquatic flowering plants. The researchers, led by garden researchers Associate Professor Sean Graham and his graduate students Jeffery Saarela (now at the Canadian Museum of Nature) and Hardeep Rai, discovered that these plants, once thought to be diminutive relatives of grasses and rushes, instead belong near the very root of the evolutionary tree of flowering plants. They have the water lilies as their closest living relatives. The flowering plants began to diversify at least 135 million years ago, in the age of the dinosaurs.

Graham and his students collaborated on this project with colleagues at the University of California, Davis, the Royal Botanical Gardens in Sydney, Australia, the University of Zurich, and Harvard University. The researcher team examined numerous genes from the two genera of Hydatellaceae, Hydatella and Trithuria. Their results are supported with a detailed consideration of Hydatellaceae plant anatomy and morphology.

The family Hydatellaceae has about ten species in two genera, Hydatella and Trithuria. The plants stand a few centimetres tall (or less) at maturity, and have multiple, minute, unisexual flowers (each lacking petals and sepals) that are collected into a compact flowering head. They grow and flower under water (up to a depth of a metre), or at the edges of drying pools. Hydatellaceae were previously thought to be monocots (a large and diverse group of the flowering plants that includes grasses, sedges, gingers, palms and onions) – largely on the basis of their narrow, pointed leaves. They are native to Australia, India and New Zealand.

The family is rather poorly known, and many details of its biology remain to be discovered. Today’s announcement overturns some previous ideas on the early evolution of flowering plants such as the water lilies – and is the first time that a family has been ejected from the monocots.

Posted by Daniel Mosquin at 11:00 AM

Ant Uses Herbicide to Create Habitat

Category(-ies): Plant Relationships

Curious tracts of Amazonian rainforest containing only a single species of tree, Duroia hirsuta, have puzzled people who have encountered them. Locals called them devil's gardens, referring to the belief that evil spirits created them. Botanists had suspected allelopathy, a process where one plant suppresses the growth of others by secreting toxins. Studies by Stanford University researchers indicate that the devil's gardens are actually created by an ant species that builds its nests in D. hirsuta trees. The ant, Myrmelachista schumanni, poisons other plants around the host trees with formic acid, a toxin commonly produced by ants.

Link: Ants, not evil spirits, create poisonous devil’s gardens in the Amazon rainforest a Stanford University news report

Posted by Eric La Fountaine at 3:08 PM

Weeds Harbour Grape Disease

Category(-ies): Plant Diseases and Pests , Plant Relationships

New research indicates that one of the most destructive diseases of grapes, Pierce's disease, is present in many of the common weeds found in California vineyards. Insect pests spread the bacterial infection to grapes. The level of infection varied greatly among host species in different environmental conditions. Scientists are evaluating the individual responses of weeds to the disease. The findings suggest that better weed control in fields and adjacent areas will aid in suppression of the disease.

Link: Vineyard Weeds Found to Host Pierce’s Disease of Grapes from Newswise

Posted by Eric La Fountaine at 10:00 AM

Burning to Regenerate Aspen Woodlands

Category(-ies): Plant Conservation , Plant Relationships

Aspen woodlands are declining in western Canada and the US. The hardwood groves provide a wildlife habitat that is much more diverse than the coniferous forests that are replacing them in many areas. Populus tremuloides reproduce primarily by vegetative means, sprouting suckers from existing root systems after fires or other disturbances. Without periodic wildfires aspen groves become dominated by conifers that tower over them, blocking needed sunlight.

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Posted by Eric La Fountaine at 11:39 AM | Comments (0)

Making the Garden Attractive to People and Wildlife

Category(-ies): Plant Relationships , Plants in the Landscape

Gardeners in the northern hemisphere will soon be busy with fall cleanup - trimming back all the dried plants and raking everything into the compost pile to make everything neat and tidy. It might be a good idea to allow a little mess in the garden this fall. As space for wildlife diminishes, animals and plants can be given a little space in home gardens.

Leaving dried seed heads on plants provides food for birds and other creatures during the winter. Leaving some leaves and twigs can provide habitat for creatures. The hardest part of doing this can be developing a new sense of aesthetics that allows for the beauty of nature's natural process of decay. It is not necessary to let the garden go wild, just allow a little space for nature.

Richard Burkmar comments on this.

Link: Gardening for Yourself from Space For Nature

Posted by Eric La Fountaine at 7:57 AM

Treehoppers?

Category(-ies): Plant Relationships

Most grasshoppers live in the grass as one would expect from the name. But at least one grasshopper prefers trees to grass. A rare grizzly spur-throat grasshopper, Melanoplus punctualatus was recently found by a Kansas middle-school student, participating in a schoolyard prairie project. The insect is native to eastern and southern forests in the USA. It is rarely seen in other areas. A local entomologist confirmed the identification and is studying the feeding habits of the group of insects found in the area.

Links:

• Grasshopper Takes to the Trees on Prairie Research Site from Kansas City infoZine


• This Grasshopper Prefers Trees from Live Science

Posted by Eric La Fountaine at 2:02 PM | Comments (0)

Plant Insect Interactions of Ancient Times

Category(-ies): Plant Diseases and Pests , Plant Relationships

Researchers are examining fossils from Patagonia and three sites in North America to gain insight into the historic biodiversity of the regions. Insect fossils are rarely found. By studying the damage caused by insects on the more abundant plant fossils, researchers are able to evaluate the type and level of insect feeding in prehistoric times. Life in Patagonia is among the most varied on the planet. The research shows that the region's biodiversity exceeded that of the other research sites as long as 52 million years ago.

Link: Fossil Patagonian plants show high insect feeding diversity 52 million years ago from EurekAlert

Posted by Eric La Fountaine at 5:56 PM | Comments (0)

The Science of Gardening

Category(-ies): Botanical Resources , Plant Relationships , Plants, Food and Medicine

In a recent issue of the Christian Science Monitor, writer Jim Regan reviews the latest addition in the Accidental Scientist series from the Exploratorium, the website of the Museum of Science in San Francisco. Even if, like Mr. Regan, you are not a gardener, you will enjoy the friendly perspective in which the photos, videos and interactive displays are presented.

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Posted by Eric La Fountaine at 4:07 PM | Comments (0)

The Darwinian Interlude

Category(-ies): Plant Relationships

Microbiologist Carl Woese makes an argument for a new biological model based on communities and eco-systems rather than on genes and molecules. He theorizes that in the earliest days of life’s existence on the planet genetic information was shared on a lateral basis between life forms. At some point a bacterium developed that kept its genetic innovation to itself and began to out compete other forms of life. Thus the era of Darwinian evolution began.

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Posted by Eric La Fountaine at 2:41 PM | Comments (0)

Bumblebees Follow Leaders in New Territory

Category(-ies): Plant Relationships

Researchers at Queen Mary, University of London have shed light on how bumblebees select flowers. In a lab experiment, bees were given choices of artificial flowers. When confronted with unfamiliar choices, the insects preferred to feed from flowers where another bee was already collecting rather than to experiment on their own. When visiting familiar flower species, the bees made their own selections regardless of others' presence.

Link: Bumblebees copy one another when contending with unfamiliar flowers
from EurekAlert

Posted by Eric La Fountaine at 4:13 PM

Genetic Assessment of Citrus Collection Reveals Close Relations

Category(-ies): Plant Conservation , Plant Relationships

The USDA Agricultural Research Service's National Clonal Germplasm Repository for Citrus and Dates has nearly 1,000 citrus accessions in its collection. Scientist recently assessed the genetic makeup of the collection, using molecular markers. Researchers found that most of the genetic diversity was found in a small percentage of the collection, indicating the likelihood that many of the citrus varieties are hybrids of a few wild types.

Citrus hybridizes readily and given its long history of cultivation by humans, it is likely that selective breeding produced many new strains.

Links:

• From a Few Wild Ancestors, a Citrus Cornucopia from the Agricultural Research Service (ARS) of the USDA


• A Citrus Mystery: Who’s Who in the Nation’s Largest Citrus Collection? from ARS, republished from Agricultural Research Magazine

Posted by Eric La Fountaine at 4:45 PM | Comments (0)

India's Mizoram State Prepares for Bamboo Bloom

Category(-ies): Plant Relationships

Every 48 years in India's Mizoram state wild bamboo blooms in unison and after fruiting the plants die. In 1959, as in previous blooms, rats gorged on the abundant fruits and their population soared. After the supply of bamboo fruit was exhausted, the rats turned to the farmer�s crops. Famine followed. Authorities hope to be better prepared when the bloom comes again in 2007.

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Posted by Eric La Fountaine at 4:43 PM

The Emotional Impact of Flowers

Category(-ies): Plant Relationships

Humans have grown flowers for at least 5,000 years although most offer us no food or other obviously useful products. Modern floriculture is a multibillion-dollar industry. What caused humans to pursue this relationship? A team of researchers at Rutgers University theorizes that flowers produce positive emotional reactions that reward people for the efforts of cultivating the plants.

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Posted by Eric La Fountaine at 2:15 PM

British Charities Encourage Gardeners to Support Wildlife

Category(-ies): Plant Conservation , Plant Relationships , Plants in the Landscape

The Royal Horticultural Society has launched a major appeal to fund efforts promoting biodiversity. It has teemed up with the Wildlife Trusts to create a project called Wild About Gardens, a program to help educate gardeners on practices that will foster wildlife. The RHS will study the distribution and ecology of wildlife found in its gardens to better understand how urban gardeners can encourage wildlife.

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Posted by Eric La Fountaine at 4:40 PM

The Optimum Distance for Plant Migration

Category(-ies): Plant Discoveries , Plant Relationships

Botanist, Jane Molofsky has conducted experiments in plant migration using a common N. American weed, Pennsylvania bittercress. The weed was a good candidate for study. It has a short two and a half month life cycle and its seeds burst forth from the parent, scattering a good distance. The experiment looks at the natural spacing required to sustain plant populations.

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Posted by Eric La Fountaine at 3:20 PM

Gardening for the Birds

Category(-ies): Plant Relationships , Plants in the Landscape

Although annual garden bird surveys in Wales seem to indicate declining populations in recent years, bird sightings in one neighbourhood are on the rise. Bird landings in one garden in Roath have tripled, since it's owners first began taking part in annual bird counts, in 1966. Residents of the neighbourhood attribute much of the population increase to the natural gardening methods that have been adopted in the area.

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Posted by Eric La Fountaine at 2:48 PM

Rafflesia and Mitrastema

Category(-ies): Plant Relationships

Deciphering the nearest living relatives of non-chlorophytic parasitic plants has been difficult; scientists looking at plant relationships often use changes within the DNA of the chloroplasts to determine how plants are related. Researchers at Western Michigan University, Universiti Kebangsaan Malaysia and Sabah Parks (Malaysia) instead looked at mitochondrial DNA (mtDNA), which is not often used, and were able to determine that Rafflesia (the plant with the largest flower) and Mitrastema are not closely related. This suggests that parasitism has evolved multiple times in different lineages of plants.

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Posted by Daniel Mosquin at 5:20 PM