Archive for the ‘plant science’ Category
Plant rhododendrons to protect from bugs
Plants emit compounds to both attract and repel insects. Plants planted near rhododendrons can absorb and emit chemicals given off by rhododendrons to protect themselves from insects.
Scandinavian Scientists have discovered that a species of tree defends itself from herbivore attack by using chemicals emitted by neighbouring plants. The study, published today in New Phytologist, reveals how a species of birch tree adsorbs chemical compounds from neighbouring marsh tea plants, Rhondodendron tomentosum, in a unique ‘defence by neighbour strategy.’
The team from Finland, led by Prof. Jarmo Holopainen from the University of Eastern Finland, were conducting studies into emissions of forest and peat land plants when they discovered previously unreported compounds for mountain birch from their foliage emissions. The compounds were emitted by a species of rhododendron growing nearby.
“It is well known that many plant species start to emit chemical compounds after damage by herbivores,” said the co-author Dr. Sari Himanen, from Agrifood Research Finland. “In an earlier study we accessed the compounds emitted from mountain birch following Moth feeding damage and we found that some of the trees growing next to Rhondodendron tomentosum also emitted residual amounts of the compounds ledene, ledol and palustrol. This resulted in the idea to experimentally test whether these sticky semivolatiles could actually protect neighbouring birch trees from the attention of attacking herbivores such as feeding moths. Based on experimentation in the field, in a natural habitat and in the laboratory, we discovered that a novel, potentially also ecologically meaningful effect for neighbour-emitted foliage-adsorbed semi-volatiles might take place in a boreal environment.”
Plant emissions can have several roles, including the attraction or deterrence of herbivores. Some cause an indirect defence by attracting a herbivorous natural enemy, but it is extraordinary for one plant to benefit directly from another plant’s emissions.
Read more Plants discover the benefits of good neighbors in strategy against herbivores
Phosphate poor soils increase hairy roots
Plants grown in soils low in phosphates grow hairy roots in the search for nutrients. Now scientists have discovered the gene that turns on hairy roots and hope to use it to develop food crops that will grow in poor soils or with less fertilizer.
When crops such as barley and wheat are grown on soils containing small amounts of phosphate it is known that those plants with long hairs on their roots give higher yields than those with short hairs. Similarly, long-haired beans grown on the nutrient-poor tropical soils of Central America do much better than short haired varieties.
Root hairs burrow into the soil like tiny ‘mining machines’ releasing acids and other scouring chemicals that crack open rocky minerals releasing valuable nutrients, such as iron and phosphate, that are necessary for plant growth.
Now, for the first time, scientists have found the mechanism that controls the growth of these specialised nutrient-excavating cells. They discovered that a master regulatory gene called RSL4 acts like a switch; hair cells grow when the gene is turned on and growth stops when it is off. read more
More information:
A basic helix-loop-helix transcription factor controls cell growth and size in root hairs
Discovery of nutrient mining machine in plants
Trees retaliate when their fig wasps don’t service them
It would seem trees are not as dumb as they first appear. When wasps try to lay eggs from outside the flower with out pollinating the flower, instead of inside the flower while spreading pollen the trees drop the fruit containing the baby wasps to death.
While trees often drop unpollinated flowers, they will often hold onto the galls containing the wasps and provide themselves with a future generation of pollinators.
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 published in the Proceedings of the Royal Society B (published online Jan. 13). ( read more read more about tree retaliation )
More information
Abstract
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Tobacco plants change pollinators to ditch worms
Sure, the hawkmoth does a good job of pollinating the plant, Nicotiana attenuata, which grows in the Western United States and flowers at night. But the hawkmoth has this annoying habit of leaving behind its eggs, which develop into caterpillars that like nothing better than to eat the plant.
So N. attenuata strikes back in a novel way, according to scientists at the Max Planck Institute for Chemical Ecology in Jena, Germany. As they describe in Current Biology, it shifts the time of its flowering to mornings and attracts a different pollinator, a hummingbird. (NYT Science, Plant switches pollinators when caterpillars strike)
