A plant is said to be a hyperaccumulator if it can concentrate the pollutants in a minimum percentage which varies according to the pollutant involved (for example: more than 1000 mg/kg of dry weight for nickel, copper, cobalt, chromium or lead; or more than 10,000 mg/kg for zinc or manganese). This capacity for accumulation is due to hypertolerance, or phytotolerance: the result of adaptative evolution from the plants to hostile environments through many generations. A number of interactions may be affected by metal hyperaccumulation, including protection, interferences with neighbour plants of different species, mutualism (includingmycorrhizae, pollen and seed dispersal), commensalism, and biofilm.
|Cd–Cadmium||T-||Pistia stratiotes||Water lettuce||Cu(T), Hg(H), Cr(H)||Pantropical, Origin South U.S.A.; aquatic herb|
Invited to see my friend’s new kitchen I wanted to bring her a small surprise.Of course it pretty soon turned out that a flower is the best option-what can be better as preparing breakfast in a new modern kitchen, looking at beautiful flowers and looking forward to a new day? No wonder as soon as I came to nursery this Crossandra fortuna was the one I picked for my friend-look at the vivid flowers and shiny leaves!And her name!On my way to my friend’s house I was thinking of many Indian woman buying Kanakamparam (Indian name for Crossandra) at street markets to make karnakamparam garlands for their hair, wishing to have a great day.
Edwin Lord Weeks: A Street Market Scene, India” oil on Canvas, location: Private collection
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Looking forward to seeing you! Tamara
All too often I walk down my garden without seeing many little neighbors of mine living down there.This Sunday was a sunny one and it was impossible not to see this working guy-Argiope bruennichi, spinning under hot sun(I say guy as females are much smaller). I took some pics immediately ,for at least three reasons.First ,look at his prey-isn’t he quiet a catcher? Second,look at white silk zig-zag pattern-it is interesting that it is still uncertain why spiders build stabilimenta. Third,so many people hate or are afraid of spiders-without reason(at rational level at least)!Fourth,this guy is actually recycling his silk web (have a look down here)!
(Scopoli, 1772)The spider builds a spiral orb web at dawn or dusk, commonly in long grass a little above ground level, taking it approximately an hour. The prominent zigzag shape called the stabilimentum, or web decoration, featured at the centre of the orb is of uncertain function, though it may be to attract insects.When a prey item is first caught in the web, Argiope bruennichi will quickly immobilise its prey by wrapping it in silk. The prey is then bitten and then injected with a paralysing venom and a protein dissolving enzyme.From: http://en.wikipedia.org/wiki/Argiope_bruennichi
Originally the decorations were thought to stabilize the web (hence the term stabilimentum), though this theory has since been dismissed. One more recent theory is that web decorations attract prey by reflecting ultraviolet light. Light in the ultraviolet part of the spectrum is known to be attractive to many species of insects.While the most conspicuous and well-studied decorations are constructed entirely of silk (for example in Argiope), some spiders combine silk with other items such as egg sacs and debris (for example in Cyclosa).From :http://en.wikipedia.org/wiki/Web_decorations
Webs allow a spider to catch prey without having to expend energy by running it down. Thus it is an efficient method of gathering food. However, constructing the web is in itself an energetically costly process because of the large amount of protein required, in the form of silk. In addition, after a time the silk will lose its stickiness and thus become inefficient at capturing prey. It is common for spiders to eat their own web daily to recoup some of the energy used in spinning. The silk proteins are thus recycled.From http://en.wikipedia.org/wiki/Spider_web: