Haustoria
/hɔˈstɔriə/
Definition
Haustoria are specialized feeding structures produced by parasitic plants and some plant-pathogenic fungi. They penetrate or closely connect with a host’s tissues to draw water, minerals, and often sugars without functioning as ordinary roots or leaves. In parasitic plants such as dodder or mistletoe, haustoria link to the host’s vascular tissue, especially xylem and sometimes phloem, which carry water and sugars through the plant.
Function in Plants
- Nutrient connection: In parasitic plants, haustoria create the physical link that lets the parasite tap into a host’s water and dissolved minerals, and in some species, sugars from the host’s transport tissues.
- Host tissue targeting: Their effect depends on which host tissue they reach. Contact with xylem supports water uptake, while access to phloem, the sugar-conducting tissue, can supply organic nutrients.
- Plant group relevance: Haustoria are a key feature in many parasitic flowering plants, including dodders and broomrapes. Because of this, they are important in studying the evolution of plant parasitism.
- Visible impact on hosts: A host plant connected by haustoria may show reduced vigor, stunting, or nutrient stress, especially when the parasite is numerous or well established.
Related Terms
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Root
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Vascular tissue
Vascular tissue is the plant transport system, made of xylem and phloem. Xylem carries water and dissolved minerals…
Xylem
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Phloem
Phloem is the plant vascular tissue that transports sugars and other organic nutrients made during photosynthesis from…
Mycorrhiza
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