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Carnivorous Carnivorous plants plants Carnivorous plants Carnivorous plants are plants are plants that derive some or most of that derive some or most of their nutrients (but not their nutrients (but not energy) from trapping and energy) from trapping and consuming animals or consuming animals or protozoans, typically insects protozoans, typically insects and other arthropods. and other arthropods. Carnivorous plants appear Carnivorous plants appear adapted to grow in places adapted to grow in places where the soil is thin or where the soil is thin or poor in nutrients, especially poor in nutrients, especially nitrogen, such as acidic bogs nitrogen, such as acidic bogs and rock outcroppings. and rock outcroppings. Charles Darwin wrote the Charles Darwin wrote the first well-known treatise on first well-known treatise on carnivorous plants in 1875. carnivorous plants in 1875.

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Page 1: Carnivorous  plants

CarnivorousCarnivorous plants plants

Carnivorous plantsCarnivorous plants are plants are plants that derive some or most of their that derive some or most of their nutrients (but not energy) from nutrients (but not energy) from trapping and consuming animals or trapping and consuming animals or protozoans, typically insects and protozoans, typically insects and other arthropods. Carnivorous other arthropods. Carnivorous plants appear adapted to grow in plants appear adapted to grow in places where the soil is thin or places where the soil is thin or poor in nutrients, especially poor in nutrients, especially nitrogen, such as acidic bogs and nitrogen, such as acidic bogs and rock outcroppings. Charles Darwin rock outcroppings. Charles Darwin wrote the first well-known treatise wrote the first well-known treatise on carnivorous plants in 1875.on carnivorous plants in 1875.

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True carnivory is thought to have evolved independently six times in five different orders of flowering plants, and these are now represented by more than a dozen genera. These include

about 630 species that attract and trap prey, produce digestive enzymes, and absorb the resulting available

nutrients. Additionally, over 300 protocarnivorous plant species in several genera show some but not all these

characteristics.

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Five basic trapping mechanisms are found in

carnivorous plants

1. Pitfall traps (pitcher plants) trap prey in a rolled leaf that contains a pool of digestive enzymes or bacteria.

2. Flypaper traps use a sticky mucilage3. Snap traps utilize rapid leaf movements4. Bladder traps suck in prey with a bladder

that generates an internal vacuum5. Lobster-pot traps force prey to move towards

a digestive organ with inward-pointing hairs

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These traps may be active or These traps may be active or passive, depending on passive, depending on

whether movement aids the whether movement aids the capture of prey. For example, capture of prey. For example, TriphyophyllumTriphyophyllum is a passive is a passive

flypaper that secretes flypaper that secretes mucilage, but whose leaves do mucilage, but whose leaves do not grow or move in response not grow or move in response to prey capture. Meanwhile, to prey capture. Meanwhile, sundewssundews are active flypaper are active flypaper traps whose leaves undergo traps whose leaves undergo

rapid acid growth, which is an rapid acid growth, which is an expansion of individual cells as expansion of individual cells as

opposed to cell division. The opposed to cell division. The rapid acid growth allows the rapid acid growth allows the sundew tentacles to bend, sundew tentacles to bend, aiding in the retention and aiding in the retention and

digestion of prey digestion of prey

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Pitfall traps

HeliamphoraHeliamphora, the sun pitche , the sun pitche plant. In this genus, the traps plant. In this genus, the traps

are clearly derived are clearly derived evolutionarily from a simple evolutionarily from a simple rolled leaf whose margins rolled leaf whose margins

have sealed together. These have sealed together. These plants live in areas of high plants live in areas of high

rainfall in South America such rainfall in South America such as Mount Roraima and as Mount Roraima and

consequently have a problem consequently have a problem ensuring their pitchers do not ensuring their pitchers do not overflow. To counteract this overflow. To counteract this

problem, natural selection has problem, natural selection has favoured the evolution of an favoured the evolution of an overflow similar to that of a overflow similar to that of a

bathroom sink—a small gap in bathroom sink—a small gap in the zipped-up leaf margins the zipped-up leaf margins allows excess water to flow allows excess water to flow

out of the pitcher. out of the pitcher.

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Heliamphora Heliamphora is a member of the

Sarraceniaceae, a New World family in the order Ericales(heathers and allies). Heliamphora is limited to South America, but the family contains two other genera, Sarracenia and Darlingtonia, which are endemic to the Southeastern United States (with the exception of one species) and California respectively. S. purpurea subsp. purpurea (the northern pitcher plant) has a more cosmopolitan distribution, found as far north as Canada.

Sarracenia is the pitcher plant genus most commonly encountered in cultivation, because it is relatively hardy and easy to grow.

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Darlingtonia californica

the cobra plant, possesses an adaptation also found in Sarracenia psittacina and, to a lesser extent, in Sarracenia minor: the operculum is balloon-like and almost seals the opening to the tube. This balloon-like chamber is pitted with areolae, chlorophyll-free patches through which light can penetrate. Insects, mostly ants, enter the chamber via the opening underneath the balloon. Once inside, they tire themselves trying to escape from these false exits, until they eventually fall into the tube. Prey access is increased by the "fish tails", outgrowths of the operculum that give the plant its name. Some seedling Sarracenia species also have long, overhanging opercular outgrowths; Darlingtonia may therefore represent an example of neoteny.

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The second major group of pitcher plants are the monkey cups or tropical pitcher plants of the genus Nepenthes. In the hundred or so

species of this genus, the pitcher is borne at the end of a tendril, which grows as an extension to

the midrib of the leaf. Most species catch insects, although the larger ones, particularly N.

rajah, also occasionally take small mammals and reptiles. These pitchers represent a

convenient source of food to small insectivores. N. bicalcarata possesses two sharp thorns that

project from the base of the operculum over the entrance to the pitcher, providing some

protection from raids by freeloading mammals.

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The pitfall trap has evolved independently in at least two other groups. The Albany pitcher plant

Cephalotus follicularis is a small pitcher plant from Western Australia, with

moccasin-like pitchers. The rim of its pitcher's opening (the peristome) is

particularly pronounced (both secrete nectar) and provides a thorny overhang

to the opening, preventing trapped insects from climbing out. The lining of

most pitcher plants is covered in a loose coating of waxy flakes, which are

slippery for insects, prey that are often attracted by nectar bribes secreted by the peristome and by bright flower-like anthocyanin patterning. In at least one species, Sarracenia flava, the nectar

bribe is laced with coniine, a toxic alkaloid also found in hemlock, which

probably increases the efficiency of the

traps by intoxicating prey.

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Flypaper traps

The flypaper trap is based on a sticky

mucilage, or glue. The leaf of flypaper

traps is studded with mucilage-

secreting glands, which may be short

and nondescript (like those of the butterworts), or long and mobile

(like those of many sundews).

Flypapers have evolved

independently at least five times.

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Closely related to Drosera is the Portuguese dewy

pine, Drosophyllum, which differs from the sundews in

being passive. Its leaves are incapable of rapid movement or growth.

Unrelated, but similar in habit, are the Australian rainbow plants (Byblis).

Drosophyllum is unusual in that it grows under near-desert conditions; almost all other carnivores are

either bog plants or grow in

moist tropical areas.

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Recent molecular data (particularly the production of plumbagin) indicate that the remaining flypaper,

Triphyophyllum peltatum, a member of the Dioncophyllaceae, is closely related to

Drosophyllum and forms part of a larger clade of carnivorous and non-carnivorous plants with the

Droseraceae, Nepenthaceae, Ancistrocladaceae and Plumbaginaceae. This plant is usually encountered

as a liana, but in its juvenile phase, the plant is carnivorous. This may be related to a requirement

for specific nutrients for flowering.

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Snap traps

The only two active snap traps—the Venus flytrap (Dionaea muscipula) and the waterwheel plant (Aldrovanda vesiculosa)—are believed to have had a common ancestor with similar adaptations. Their trapping mechanism has also been described as a "mouse trap" or "man trap", based on their shape or rapid movement. However, the term snap trap is preferred as other designations are misleading, particularly with respect to the intended prey. Aldrovanda is aquatic and specialised in catching small invertebrates; Dionaea is terrestrial and catches a variety of arthropods, including spiders.

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The traps are very similar, with leaves whose terminal section is divided into two lobes, hinged along the midrib. Trigger hairs (three on each lobe in Dionaea muscipula, many more in the case of Aldrovanda) inside the trap lobes are sensitive to touch. When a trigger hair is bent, stretch-gated ion channels in the membranes of cells at the base of the trigger hair open, generating an action potential that propagates to cells in the midrib.These cells respond by pumping out ions, which may either cause water to follow by osmosis (collapsing the cells in the midrib) or cause rapid acid growth.The mechanism is still debated, but in any case, changes in the shape of cells in the midrib allow the lobes, held under tension, to snap shut,flipping rapidly from convex to concave and interring the prey. This whole process takes less than a second. In the Venus flytrap, closure in response to raindrops and blown-in debris is prevented by the leaves having a simple memory: for the lobes to shut, two stimul are required, 0.5 to 30 seconds apart.

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The snapping of th

e leaves i

s a ca

se of th

igmonasty

(undirecte

d movement in

resp

onse to

touch

). Furth

er

stimulatio

n of the lo

be's internal s

urface

s by th

e

strugglin

g inse

cts ca

uses t

he lobes t

o grow together

towards the prey (t

higmotropism

), sealin

g the lo

bes

hermetic

ally and fo

rming a st

omach in

which

digestion

occurs

over a perio

d of one to

two w

eeks. Le

aves can

be reuse

d three or f

our tim

es before th

ey become

unresponsiv

e to st

imulatio

n.

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Bladder traps

Bladder traps are exclusive to the genus Utricularia, or bladderworts. The bladders pump ions out of their interiors. Water follows by osmosis generating a partial vacuum inside the bladder. The bladder has a small opening, sealed by a hinged door. In aquatic species, the door has a pair of long trigger hairs. Aquatic invertebrates such as Daphnia touch these hairs and deform the door by lever action, releasing the vacuum. The invertebrate is sucked into the bladder, where it is digested. Many species of Utricularia (such as U. sandersonii) are terrestrial, growing on waterlogged soil, and their trapping mechanism is triggered in a slightly different manner. Bladderworts lack roots, but terrestrial species have anchoring stems that resemble them. Temperate aquatic bladderworts generally die back to a resting turion during the winter months, and U. macrorhiza appears to regulate the number of bladders it bears in response to the prevailing nutrient content of its habitat.

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Lobster-pot traps A lobster-pot trap is a chamber that is

easy to enter, and whose exit is either difficult to find or obstructed by inward-pointing bristles. Lobster pots are the trapping mechanism in Genlisea, the corkscrew plants. These plants appear to specialise in aquatic protozoa. A Y-shaped modified leaf allows prey to enter but not exit. Inward-pointing hairs force the prey to move in a particular direction. Prey entering the spiral entrance that coils around the upper two arms of the Y are forced to move inexorably towards a stomach in the lower arm of the Y, where they are digested. Prey movement is also thought to be encouraged by water movement through the trap, produced in a similar way to the vacuum in bladder traps, and probably evolutionarily related to it.

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Borderline carnivores

To be a fully fledged carnivore, a plant must attract, kill, and digest prey and it must benefit from absorbing the products of the digestion (mostly amino acids and ammonium ions).To many horticulturalists, these distinctions are a matter of taste. There is a spectrum of carnivory found in plants: from completely non-carnivorous plants like cabbages, to borderline carnivores, to unspecialised and simple traps, like Heliamphora, to extremely specialised and complex traps, like that of the Venus flytrap.

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The borderline carnivores include Roridula and Catopsis berteroniana. Catopsis is a borderline carnivorous bromeliad, like Brocchinia reducta. However, unlike B. reducta, which produces the

enzyme phosphatase, C. berteroniana has not been shown to produce any digestive enzymes at all.In these pitfall traps, prey simply fall into the urn, assisted by the waxy scales located on the rim.

Roridula has a more intricate relationship with its

prey.

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The plants in this genus produce sticky leaves

with resin-tipped glands and look extremely

similar to some of the larger sundews.

However, they do not directly benefit from the

insects they catch. Instead, they form a

mutualistic symbiosis with species of assassin bug (genus Pameridea), which eat the trapped

insects. The plant benefits from the

nutrients in the bugs' faeces

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• Презентацията е изработена

от Диана Филчева -8б клас

МГ “Константин Величков”

гр.Пазарджик