Parasitic plant - wikipedia Parasitic plant Cuscuta, a stem holoparasite, on an acacia tree in Pakistan A parasitic plant is a plant that derives some or all of its nutritional requirement from another living plant. They make up about 1 % of angiosperms and are in almost every biome in the world. All parasitic plants have modified roots, named haustoria ( singular : haustorium ), which penetrates the host plants, connecting them to the conductive system -- either the xylem, the phloem, or both. This provides them with the ability to extract water and nutrients from the host. Parasitic plants are classified depending on where the parasitic plant latches onto the host and the amount of nutrients it requires. Some parasitic plants are able to locate their host plants by detecting chemicals in the air or soil given off by host shoots or roots, respectively. About 4,500 species of parasitic plant in approximately 20 families of flowering plants are known. Contents 1 Classification 2 Evolution of parasitic behavior 3 Seed germination 3.1 Seed dispersal 4 Obstacles of attaching to a host 5 Host range 6 Aquatic parasitic plants 7 Importance 8 Plants parasitic on fungi 9 References 10 Further reading Classification Parasitic plants are characterized as follows : 1a. Obligate parasite -- a parasite that can not complete its life cycle without a host. 1b. Facultative parasite -- a parasite that can complete its life cycle independent of a host. 2a. Stem parasite -- a parasite that attaches to the host stem. 2b. Root parasite -- a parasite that attaches to the host root. 3a. Hemiparasite -- a plant parasitic under natural conditions, but photosynthetic to some degree. Hemiparasites may just obtain water and mineral nutrients from the host plant ; many obtain at least part of their organic nutrients from the host as well. 3b. Holoparasite - a parasitic plant that derives all of its fixed carbon from the host plant. Commonly lacking chlorophyll, holoparasites are often colors other than green. Mistletoe, an obligate stem hemiparasite For hemiparasites, one from each of the three sets of terms can be applied to the same species, e.g. Nuytsia floribunda ( Western Australian Christmas tree ) is an obligate root hemiparasite. Rhinanthus ( e.g. Yellow rattle ) is a facultative root hemiparasite. Mistletoe is an obligate stem hemiparasite. Holoparasites are always obligate so only two terms are needed, e.g. Dodder is a stem holoparasite. Hydnora spp. are root holoparasites. Plants usually considered holoparasites include broomrape, dodder, Rafflesia, and the Hydnoraceae. Plants usually considered hemiparasites include Castilleja, mistletoe, Western Australian Christmas tree, and yellow rattle. Evolution of parasitic behavior Striga witchweeds ( white, centre, attached to roots of host ) are economically important pests of the crop plants that they parasitise. Parasitic behavior evolved in angiosperms roughly 12 - 13 times independently, a classic example of convergent evolution. Roughly 1 % of all angiosperm species are parasitic, with a large degree of host dependence. The taxonomic family Orobanchaceae ( encompassing the genera Tryphysaria, Striga, and Orobanche ) is the only family that contains both holoparasitic and hemiparasitic species, making it a model group for studying the evolutionary rise of parasitism. The remaining groups contain only hemiparasites or holoparasites. The evolutionary event which gave rise to parasitism in plants was the development of haustoria. The first, most ancestral, haustoria are thought to be similar to that of the facultative hemiparasites within Tryphysaria, lateral haustoria develop along the surface of the roots in these species. Later evolution led to the development of terminal or primary haustoria at the tip of the juvenile radicle, seen in obligate hemiparasitic species within Striga. Lastly, obligate holoparasitic behavior originated with the loss of the photosynthetic process, seen in the genus Orobanche. To maximize resources, many parasitic plants have evolved self - incompatibility, to avoid parasitizing themselves. Others such as Triphysaria usually avoid parasitizing other members of their species, but some parasitic plants have no such limits. The albino redwood is a mutant Sequoia sempervirens that produces no chlorophyll ; they live on sugars from neighbouring trees, usually the parent tree from which they have grown ( via a somatic mutation ). Seed germination Parasitic plants germinate in a variety of ways. These means can either be chemical or mechanical and the means used by seeds often depends on whether or not the parasites are root parasites or stem parasites. Most parasitic plants need to germinate in close proximity to their host plants because their seeds are limited in the amount of resources necessary to survive without nutrients from their host plants. Resources are limited due in part to the fact that most parasitic plants are not able to use autotrophic nutrition to establish the early stages of seeding. Root parasitic plant seeds tend to use chemical cues for germination. In order for germination to occur, seeds need to be fairly close to their host plant. For example, the seeds of witchweed ( Striga asiatica ) need to be within 3 to 4 millimeters ( mm ) of its host in order to pick up chemical signals in the soil to signal germination. This range is important because Striga asiatica will only grow about 4 mm after germination. Chemical compound cues sensed by parasitic plant seeds are from host plant root exudates that are leached in close proximity from the host 's root system into the surrounding soil. These chemical cues are a variety of compounds that are unstable and rapidly degraded in soil and are present within a radius of a few meters of the plant exuding them. Parasitic plants germinate and follow a concentration gradient of these compounds in the soil toward the host plants if close enough. These compounds are called strigolactones. Strigolactone stimulates ethylene biosynthesis in seeds causing them to germinate. There are a variety of chemical germination stimulants. Strigol was the first of the germination stimulants to be isolated. It was isolated from a non-host cotton plant and has been found in true host plants such as corn and millets. The stimulants are usually plant specific, examples of other germination stimulants include sorgolactone from sorghum, orobanchol and alectrol from red clover, and 5 - deoxystrigol from Lotus japonicas. Strigolactones are apocarotenoids that are produced via the carotenoid pathway of plants. Strigolactones and mycorrhizal fungi have a relationship in which Strigolactone also cues the growth of mycorrhizal fungus. Stem parasitic plants, unlike most root parasites, germinate using the resources inside their endosperms and are able to survive for some time. For example, the dodders ( Cuscuta spp. ) drop their seeds to the ground ; these may remain dormant for up to five years before they a host plant nearby. Using the resources in the seed endosperm, dodder is able to germinate. Once germinated, the plant has 6 days to find and establish a connection with its host plant before its resources run out. Dodder seeds germinate above ground and then the plant sends out stems in search of its host plant reaching up to 6 cm before it dies. It is believed that the plant uses two methods of finding a host. The stem detects its host plant 's scent and orients itself in that direction. Scientists used volatiles from tomato plants ( α - pinene, β - myrcene, and β - phellandrene ) to test the reaction of C. pentagona and found that the stem orients itself in the direction of the odor. Some studies suggest that by using light reflecting from nearby plants dodders are able to select host with higher sugar because of the levels of chlorophyll in the leaves. Once the dodder finds its host, it wraps itself around the host plants stem. Using adventitious roots, the dodder taps into the host plant 's stem with a haustorium, an absorptive organ within the host plant vascular tissue. Dodder makes several of these connections with the host as it moves up the plant. Seed dispersal There are several methods of seed dispersal, but all the strategies aim to put the seed in direct contact with, or within a critical distance of, the host. The Cuscuta seedling can live for 3 -- 7 weeks and extend out 35 cm in search of the host before it dies. This is because the Cuscuta seed is large and has stored nutrients to sustain its life. This is also useful for seeds that get digested by animals and excreted out. Mistletoe use a sticky seed for dispersal. The seed sticks to nearby animals and birds and then comes into direct contact with the host. Arceuthobium seeds have a similarly sticky seed as the mistletoe but they do not rely on animals and birds, they mainly disperse by fruit explosiveness. Once the seed makes contact with the host rain water can help position the seed into a suitable position. Some seeds detect and respond to chemical stimulations produced in the host 's roots and start to grow towards the host. Obstacles of attaching to a host The parasitic plant has many obstacles to overcome in order to attach to the host. Distance from the host and stored nutrients are only some of the problems, the host 's defenses are an obstacle to overcome itself. The first hurdle is penetrating the host, the host has systems to reinforce the cell wall by protein cross-linking so that it stops the parasitic progress at the cortex of the host 's roots. The second hurdle is the host 's ability to secrete germination inhibitors. This prevents germination of the parasitic seed. The third hurdle is the host 's ability to create a toxic environment for where the parasitic plant attaches to. The host secretes phenolic compounds into the apoplast the creates a toxic environment for the parasitic plant eventually killing it. The fourth hurdle is the host 's ability to ruin the tubercle using gums and gels or injecting toxins into the tubercle. Host range Some parasitic plants are generalists and parasitize many different species, even several different species at once. Dodder ( Cassytha spp., Cuscuta spp. ) and red rattle ( Odontites vernus ) are generalist parasites. Other parasitic plants are specialists that parasitize a few or even just one species. Beech drops ( Epifagus virginiana ) is a root holoparasite only on American beech ( Fagus grandifolia ). Rafflesia is a holoparasite on the vine Tetrastigma. Plants such as Pterospora become parasites of mycorrhizal fungi. There is evidence that parasites also practice self - discrimination, species of Tryphysaria experience reduced haustorium development in the presence of other Tryphysaria. Although, the mechanism for self - discrimination in parasites is not yet known. Aquatic parasitic plants Parasitism also evolved within aquatic species of plants and algae. Parasitic marine plants are described as benthic, meaning that they are sedentary or attached to another structure. Plants and algae that grow on the host plant, using it as an attachment point are given the designation epiphytic ( epilithic is the name given to plants / algae that use rocks or boulders for attachment ), while not necessarily parasitic, some species occur in high correlation with a certain host species, suggesting that they rely on the host plant in some way or another. In contrast, endophytic plants and algae grow inside their host plant, these have a wide range of host dependence from obligate holoparasites to facultative hemiparasites. Marine parasites occur as a higher proportion of marine flora in temperate rather than tropical waters. While no full explanation for this is available, many of the potential host plants such as kelp and other macroscopic brown algae are generally restricted to temperate areas. Roughly 75 % of parasitic red algae infect hosts in the same taxonomic family as themselves, these are given the designation adelphoparasites. Other marine parasites, deemed endozoic, are parasites of marine invertebrates ( molluscs, flatworms, sponges ) and can be either holoparasitic or hemiparasitic, some retaining the ability to photosynthesize after infection. Importance Species within Orobanchaceae are some of the most economically destructive species on Earth. Species of Striga alone are estimated to cost billions of dollars a year in crop yield loss annually, infesting over 50 million hectares of cultivated land within Sub-Saharan Africa alone. Striga can infest both grasses and grains, including corn, rice and Sorghum, undoubtedly some of the most important food crops. Orobanche also threatens a wide range of important crops, including peas, chickpeas, tomatoes, carrots, and varieties of the genus Brassica ( e.g. cabbage, lettuce, and broccoli ). Yield loss from Orobanche can reach 100 % and has caused farmers in some regions of the world to abandon certain staple crops and begin importing others as an alternative. Much research has been devoted to the control of Orobanche and Striga species, which are even more devastating in developing areas of the world, though no method has been found to be entirely successful. Mistletoes cause economic damage to forest and ornamental trees. Rafflesia arnoldii produces the world 's largest flowers at about one meter in diameter. It is a tourist attraction in its native habitat. Sandalwood trees ( Santalum species ) have many important cultural uses and their fragrant oils have high commercial value. Indian paintbrush ( Castilleja linariaefolia ) is the state flower of Wyoming. The Oak Mistletoe ( Phoradendron serotinum ) is the floral emblem of Oklahoma. A few other parasitic plants are occasionally cultivated for their attractive flowers, such as Nutysia and broomrape. Parasitic plants are important in research, especially on the loss of photosynthesis during evolution. A few dozen parasitic plants have occasionally been used as food by people. Western Australian Christmas tree ( Nuytsia floribunda ) sometimes damages underground cables. It mistakes the cables for host roots and tries to parasitize them using its sclerenchymatic guillotine. Some parasitic plants are destructive while some have positive influences in their communities. Some parasitic plants damage invasive species more than native species. This results in the reduced damage of invasive species in the community. Newly emergent snow plant ( Sarcodes sanguinea ), a flowering plant parasitic on mycorrhizal fungi In many regions, including the Nepal Eastern Himalayas, parasitic plants are used for medicinal and ritual purposes. Plants parasitic on fungi About 400 species of flowering plants, plus one gymnosperm ( Parasitaxus usta ), are parasitic on mycorrhizal fungi. This effectively gives these plants the ability to become associated with many of the other plants around them. They are termed myco - heterotrophs. Some myco - heterotrophs are Indian pipe ( Monotropa uniflora ), snow plant ( Sarcodes sanguinea ), underground orchid ( Rhizanthella gardneri ), bird 's nest orchid ( Neottia nidus - avis ), and sugarstick ( Allotropa virgata ). Within the taxonomic family Ericaceae, known for extensive mycorrhizal relationships, there are the Monotropoids. The Monotropoids include the genera Monotropa, Monotropsis, and Pterospora among others. Myco - heterotrophic behavior is commonly accompanied by the loss of chlorophyll. References ^ Jump up to : Heide - Jørgensen, Henning S. ( 2008 ). Parasitic flowering plants. Leiden : Brill. ISBN 978 - 9004167506. Jump up ^ Nickrent, D.L. and Musselman, L.J. 2004. Introduction to Parasitic Flowering Plants. The Plant Health Instructor. doi : 10.1094 / PHI - I - 2004 - 0330 - 01 ( 1 ) ^ Jump up to : Westwood, James H., John I. Yoder, Michael P. Timko and Claude W. Depamphilis. `` The Evolution of Parasitism in Plants. '' Trends in Plant Science 15.4 ( 2010 ) 227 - 35. Web. Jump up ^ Stienstra, T. ( 11 October 2007 ). `` It 's no snow job - handful of redwoods are rare albinos ''. San Francisco Chronicle. Retrieved December 6, 2010. Jump up ^ Krieger, L.M. ( 2010 - 11 - 28 ). `` Albino redwoods hold scientific mystery ''. San Jose Mercury News. Retrieved 2012 - 11 - 23. Jump up ^ `` A Creepy Monster of the Forest : The Albino, Vampiric Redwood Tree ''. Discover Magazine Discoblog. Retrieved 2012 - 11 - 23. ^ Jump up to : Scott, P. 2008. Physiology and behavior of plants : parasitic plants. John Wiley & sons pp. 103 -- 112. ^ Jump up to : Runyon, J. Tooker, J. Mescher, M. De Moraes, C. 2009. Parasitic plants in agriculture : Chemical ecology of germination and host - plant location as targets for sustainable control : A review. Sustainable Agriculture Reviews 1. pp. 123 - 136. Jump up ^ Schneeweiss, G. 2007. Correlated evolution of life history and host range in the nonphotosynthetic parasitic flowering plants Orobanche and Phelipanche ( Orobanchaceae ). Journal Compilation. European Society for Evolutionary Biology. 20 471 - 478. ^ Jump up to : Lesica, P. 2010. Dodder : Hardly Doddering. Kelseya Newsletter of Montana Native Plant Society. Vol 23. 2, 6 Jump up ^ Walters, D. ( 2010 ). Plant Defense Warding off attack by pathogens, herbivores and parasitic plants. Hoboken : Wiley. ^ Jump up to : Dring, M.J. The Biology of Marine Plants. London : E. Arnold, 1982. Print. Jump up ^ Parasitic Angiosperms Used for Food ? Jump up ^ Sclerenchymatic guillotine in the haustorium of Nuytsia floribunda Archived 2006 - 07 - 26 at the Wayback Machine. Jump up ^ Li J, Jin Z, Song W ( 2012 ) Do Native Parasitic Plants Cause More Damage to Exotic Invasive Hosts Than Native Non-Invasive Hosts ? An Implication for Biocontrol. PLoS ONE 7 ( 4 ) : e34577. https://doi.org/10.1371/journal.pone.0034577 Jump up ^ O'Neill, Alexander ; Rana, Santosh ( 2017 - 07 - 16 ). `` An ethnobotanical analysis of parasitic plants ( Parijibi ) in the Nepal Himalaya ''. Journal of Ethnobiology and Ethnomedicine. 12 ( 14 ). doi : 10.1186 / s13002 - 016 - 0086 - y. Retrieved 2017 - 05 - 11. Jump up ^ Judd, Walter S., Christopher Campbell, and Elizabeth A. Kellogg. Plant Systematics : A Phylogenetic Approach. Sunderland, MA : Sinauer Associates, 2008. Print. Further reading Joel D.M. et al. Eds. ( 2013 ) Parasitic Orobanchaceae : Parasitic Mechanisms and Control Strategies. Springer, Heidelberg Digital Atlas of Cuscuta ( Convolvulaceae ) The Parasitic Plant Connection The Strange and Wonderful Myco - heterotrophs Parasitic Flowering Plants The Mistletoe Center Parasitic Plants Biology Study Guide Nickrent, Daniel L. 2002. Parasitic plants of the world. Calladine, Ainsley and Pate, John S. 2000. Haustorial structure and functioning of the root hemiparastic tree Nuytsia floribunda ( Labill. ) R.Br. and water relationships with its hosts. Annals of Botany 85 : 723 - 731. Milius, Susan. 2000. Botany under the mistletoe : Twisters, spitters, and other flowery thoughts for romantic moments. Science News 158 : 411. Hibberd, Julian M. and Jeschke, W. Dieter. 2001. Solute flux into parasitic plants. Journal of Experimental Botany 52 : 2043 - 2049. NDL : 00565987 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Parasitic_plant&oldid=853045319 '' Categories : Parasitic plants Plant physiology Hidden categories : Wikipedia articles needing page number citations from December 2017 Webarchive template wayback links Wikipedia articles with NDL identifiers Talk Contents About Wikipedia Български Català Deutsch Eesti Español Esperanto فارسی Français Gaeilge 한국어 Bahasa Indonesia Italiano עברית Latviešu Lietuvių Magyar Македонски മലയാളം Nederlands 日本 語 Polski Português Русский Српски / srpski Suomi தமிழ் Türkçe 中文 20 more Edit links This page was last edited on 2 August 2018, at 02 : 17 ( UTC ). Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: roots that enable a plant to grow on another plant are called
Answer: haustoria (singular: haustorium)