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Charles Darwin called Dionaea muscipula Ellis (Venus' flytrap) "one of the most wonderful plants in the world" because of its trapping ability - rapidly closing, snap-trap leaves, which are used to capture and digest small insects for nutrition. (Darwin C. 1875 Insectivorous plants. John Murray, London, UK ) Venus Flytrap K-12 Experiments
Venus Flytrap 
Venus Flytrap (Dionaea muscipula) is a carnivorous plant that catches and digests animal prey (mostly insects and arachnids). The trapping structure is formed by the terminal portion of each of the plant's leaves. The plant's name refers to Venus, the Roman goddess of love and plant life.
DescriptionThe Venus Flytrap is a small herb, forming a rosette of four to seven leaves, which arise from a short subterranean stem which is actually a bulb-like rhizome. Each leaf reaches a maximum size of about three to seven cm, depending on the time of year[2]; longer leaves with robust traps are generally formed after flowering. Flytraps that appear to have more leaves are generally colonies, formed by rosettes that have divided beneath the ground. 
The leaf blade is divided into two regions: a flat, heart shaped photosynthetic capable petiole, and a pair of terminal lobes hinged at the midrib, forming the trap which is actually the true leaf. The upper surface of these lobes contains red anthocyanin pigments and its edges secrete mucilage. The lobes exhibit rapid plant movements, snapping shut when stimulated by prey. The trapping mechanism is tripped when prey items stumble against one of the three hair-like trichomes that are found on the upper surface of each of the lobes. The trigger hairs must be touched twice in quick succession (which prevents non-prey stimuli such as raindrops from triggering the trap), whereupon the lobes snap shut in c. 100 ms. The edges of the lobes are fringed by stiff hair-like protrusions or cilia, which mesh together and prevent large prey items from escaping. (These protrusions, and the trigger hairs, are probably homologous with the tentacles found in this plant’s close relatives, the sundews). The holes in the meshwork allow small prey to escape, presumably because the benefit that would be obtained from them would be less than the cost of digesting them. If the prey is too small and escapes, the trap will reopen within 12 hours. Mechanism of trappingThe Venus Flytrap is one of a very small group of plants that are capable of rapid movement, such as Mimosa, the Telegraph plant, sundews and bladderworts. 
The mechanism by which the trap snaps shut involves a complex interaction between elasticity, turgor and growth. In the open, untripped state, the lobes are convex (bent outwards), but in the closed state, the lobes are concave (forming a cavity). It is the rapid flipping of this bistable state that closes the trap,[3] but the mechanism by which this occurs is still poorly understood. When the trigger hairs are stimulated, an action potential (mostly involving calcium ions — see calcium in biology) is generated, which propagates across the lobes and stimulates cells in the lobes and in the midrib between them.[4] Exactly what this stimulation does is still debated: cells in the outer layers of the lobes and midrib may rapidly secrete protons into their cell walls, loosening them and allowing them to swell rapidly by osmosis and acid growth; alternatively, cells in the inner layers of the lobes and midrib may rapidly secrete other ions, allowing water to follow by osmosis, and the cells to collapse. Both, either or neither of these mechanisms may play a role.[5] If the prey is unable to escape, it will continue to stimulate the inner surface of the lobes, and this causes a further growth response that forces the edges of the lobes together, eventually sealing the trap hermetically and forming a 'stomach' in which digestion occurs. Digestion is catalysed by enzymes secereted by glands in the lobes. Digestion takes about 10 days, after which the prey is reduced to a husk of chitin. The trap then reopens, and is ready for reuse; however, it is rare for a single trap to catch even three insects in its lifetime. HabitatThe Venus Flytrap is found in nitrogen-poor environments, such as bogs. Although it has been successfully transplanted and grown in many locales around the world, the venus flytrap is found natively only in North and South Carolina in the United States; one such place is North Carolina's Green Swamp. The nutritional poverty of the soil is the reason that the plant relies on such elaborate traps: insect prey provide the nitrogen for protein formation that the soil cannot. The venus flytrap is not a tropical plant and can tolerate mild winters. CultivationVenus Flytraps are popular as cultivated plants, although they have a reputation for being difficult to grow. This reputation is largely due to inappropriate treatment of the plants by retailers and their consequent ill-health on purchase. Venus flytraps are not houseplants and should be grown in pots under conditions that mimic those in their natural habitat. 
Venus flytraps should be kept in pots on a patio, deck or position in the garden that receives at least 6-8 hours of sunlight per day.[6] The colour of the trap leaves may be used as an indicator of sufficient light. In appropriate conditions the inside of each trap should be bright red in color for most varieties. In insufficent light the inside of the traps turn light green. Low light also causes etiolation and makes plants more susceptible to diseases. Venus flytraps are best grown in mixtures of sphagnum peat moss and/or peat often with the addition of sand, perlite or other inert salt free material. Soil pH should be in the range of 4.0 to 4.5. Venus Flytraps ideally should not be watered with tap water as accumulated salts in tap water may kill carnivorous plants. Soft water with TDS of 100 ppm or less yields good growth, both distilled water or clean rain water are ideal. The soil should be kept constantly moist by placing the pot in a tray full of water, with the root bulb of the plant allowed to be above the level of the water at least part of the time, to prevent root rot in stagnant water. There is no danger of over-watering. Venus flytraps can survive short periods of immersion underwater.[6] Some horticulturists have experimented with giving small amounts of fertiliser to Venus flytraps, usually applying diluted solutions of products formulated for epiphytes, using cotton swabs, to the plant's foliage. Beginners, however, and those without expendable plants, would be wise to avoid fertiliser in favor of insects. 
The temptation to trigger the traps manually should be resisted. Venus flytraps are entirely capable of catching their own food; thus, feeding them manually is not necessary. If for some reason a grower wishes to feed a flytrap, live insects no larger than 1/3 of the size of the trap may be used. Algal growth near the plant is an indicator of overfeeding. Healthy venus flytraps will produce scapes of white flowers in spring, however, many growers remove the flowering stem early, as flowering consumes some of the plant's energy, and reduces the rate of trap production. If allowed to flower, successful pollination will result in the production of dozens of small, shiny black seeds. Venus flytraps have a necessary winter dormancy period, triggered by nighttime temperatures below 10 °C (50 °F) and reduced day length.[6] In climates with mild winters they can be kept outside to overwinter (hardiness zone 9 or greater). The soil should be kept slightly moist and the area well ventilated to prevent the growth of grey mold. Those who live in areas with extremely cold winters (hardiness zone 8 or less) might consider placing plants in a plastic bag in the refrigerator for two to three months, starting in Autumn, although they can survive freeze-over for brief periods of time.[6] Plants can be propagated by seed, although seedlings will take several years to mature. More commonly, they may be propagated by division in spring or summer. Cultivars (Cultivated Varieties)Venus Flytraps are by far, the most commonly recognized and cultivated carnivorous plant. They are sold as houseplants and are often found at florists, hardware stores and supermarkets. Although the genus is monotypic, during the past ten years or so, large quantities of cultivars have come into the market through tissue culture of select genetic mutations. It is through tissue culture that great quantities of plants are raised for commercial markets. Some of the registered cultivated varieties include (name of originator in brackets):
An unofficial list includes many more names, with more added annually. It should be noted that none of these "variation names" are officially recognized unless the name is properly documented, registered and accepted by the only official CP name registrant, the International Carnivorous Plant Society:
Popular culture
Venus Flytrap-like plants are common in fictional works, usually in a much larger form capable of digesting a human. Probably the most famous is Audrey II in Little Shop of Horrors, a plant that needs to eat people to live (the off-Broadway play was based on a low-budget black comedy, The Little Shop of Horrors, in which the plant was named Audrey Jr.). Other fictional outings include the Philippine comic Darna, where the villain Flaviana turns Venus Flytraps into monsters as a defense. A one-time villain on Mighty Morphin Power Rangers was the Invenusable Flytrap, a humanoid plant creature. There was also a character named Venus Flytrap on the television sitcom WKRP in Cincinnati. Cartoons frequently make use of monstrous plants; examples include, but certainly are not limited to Inspector Gadget, Darkwing Duck, The Simpsons and Zetsu, a villain character in the manga series, Naruto. Video games such as Super Mario Bros. use similar creatures called piranha plants as enemies and Rampage: Total Destruction has a venus fly trap-like plant named Venus. Another video game, called Venus the Flytrap, involves a robotic fly which tries to destroy other robotic insects.[7] The Infocom text adventure game Leather Goddesses of Phobos features a giant (mobile) flytrap which attempts to eat the player's character. The Sims 2: University features an unlockable object, the Cow Plant, which will lure non-player characters with a cake lure and eat them if not fed regularly. The Gravemind in Halo 2 resembles a large venus flytrap. References
Further reading
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia Encyclopedia article "Venus Flytrap" |
