Plant behavior

Yes, Plant behavior!
Here is a link for a very interesting article
http://www.sciencenew...

Here are a few excerpts. There is much more info in the article than what I copied for you here.

Volatile messages

It’s not neighboring plants but insects that come to the rescue when a plant cries for help. Karban, in his 2008 paper, argued that these behaviors amount to a plant version of communication.

When mites or caterpillars bite into leaves or stems, the attacked plant releases volatile compounds. It’s not just that sap dribbling from an open wound happens to have a scent. In corn, for example, insects boring into the stem prompt leaves to release complex blends of volatile chemicals.

Blends include a lot of information. Some plants enduring the indignity of a researcher snipping their leaves will release volatiles, but not of quite the same aroma as when caterpillars bite.

Some of the insects that prey on other insects react to these volatiles, swarming to the attacked plant to dine on the attackers. Research has found that certain of these ambulance-chasing predators respond selectively, flying toward the aromatic news of pests they prefer to eat while ignoring aromas from attacks by species they don’t fancy. For example, a little wasp that can only manage to inject its eggs into young caterpillars reacts to volatiles of plants under the attack of such tender youngsters. But the wasp doesn’t respond to volatiles from infestations inflicted by older caterpillars.

Neighboring plants can eavesdrop on the volatile signals too, and some respond by priming their own defenses.

Karban is willing to use the term “communication” for these chemical outbursts. He acknowledges, however, that strict definitions of communication demand that both the cue-emitter and the receiver benefit from the exchange. Plant volatiles that bring insect rescue may fit even this tougher definition, he says.

Fighting tooth and chemical

Consider foraging, Metlen says. Iconic scenes of animal behavior star cheetahs streaking toward an antelope lunch. Underfoot, it turns out, the plants are hunting too, just by different means.
access

Exposed to a secretion from an invasive knapweed, the root of a blanketflower within an hour responds with its own secretion (right, shown as gel acidifies and turns yellow). At left is an unexposed root. Tiffany Weir et al./Planta 2006

In a very basic sense, plants hunt by sending out roots. Decades of research have established that plants are strategic, allotting root growth to the promising patches and skimping on dead zones.

Plants also have their version of the cheetah pounce, but it’s chemical. Metlen’s favorite example, he says, comes from a study of fava beans by Long Li at China Agricultural University in Beijing and a network of colleagues. Like other plants, the beans need phosphorus. When researchers put the plants in phosphorus-poor agar gel, the beans took “action.” They acidified the material around their roots, causing malate and citrate concentrations in the agar to increase in such quantities that the gel’s pH dropped by about two units within six hours. Driving down soil pH increases plants’ phosphorus uptake, so chemically those bean roots were chasing and grabbing the food they needed.

One plant Metlen is studying now, spotted knapweed, adds a root-war twist to the chemical-pounce scenario. Back in its native Eurasian range, Centaurea maculosa grows here and there as an occasional member of mixed-plant communities. Its roots exude a substance called catechin, which makes phosphorus more available in certain soils.

Spotted knapweed has moved to North America. Where it once had an occasional presence, it is now a land grabber. Knapweed blankets entire slopes and pushes out native vegetation. One of the secrets for its new success may be the catechin. European neighbors of knapweed don’t seem bothered by catechin seeps, but some North American species can’t cope. A handy dietary aid has turned into an invader’s chemical weapon.

It’s root versus root, and research, including a 2006 Planta paper, suggests that some native species fight back, chemically of course. A lupine and a blanketflower can still grow when knapweed erupts in the neighborhood. Expose the two species to catechin and their roots exude extra oxalate, four times the normal level for the blanketflower and 40 times normal for the lupine. The oxalate may defang the catechin, with protection extending beyond the blanketflower and lupines to other native species growing near enough.

Table of Contents

Page title Most recent update Last edited by
5 nutrient dense and 42 edible flowers - links April 8, 2012 6:08 PM Cindy M.
More links, videos, and books May 20, 2011 4:43 PM Cindy M.
Eatable flowers July 8, 2009 10:25 AM Cindy M.
useful books, websites, and excerpts October 18, 2010 7:36 AM Cindy M.
Plant behavior June 11, 2009 5:38 PM Cindy M.
Southern dining menu before beans and corn June 7, 2009 4:54 PM Cindy M.
Foraging in the City (Portland Oregon) June 7, 2009 4:47 PM Cindy M.
About EDIBLE WEED WALKS and PLANT CLASSES April 22, 2010 5:34 AM Cindy M.

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