ERGOT THE GENUS CLAVICEPS PDF

Life cycle[ edit ] An ergot kernel, called a sclerotium, develops when a spore of fungal species of the genus Claviceps infects a floret of flowering grass or cereal. The infection process mimics a pollen grain growing into an ovary during fertilization. Infection requires that the fungal spore have access to the stigma ; consequently, plants infected by Claviceps are mainly outcrossing species with open flowers , such as rye Secale cereale and ryegrasses genus Lolium. The proliferating fungal mycelium then destroys the plant ovary and connects with the vascular bundle originally intended for seed nutrition.

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Claviceps purpurea var. Their lifecycles are complex. The sclerotia develop in place of the seeds once spores of a Claviceps fungus have infected grass flowers. Ryegrass is particularly susceptible because of its open flower form.

The Ergot mycelium then destroys the flower ovary and ultimately produces vast numbers of conidia asexual spores that can infect grass florets. Ergot infects only the ovary of cereal and grass plants; other part of the plant are unaffected. Visible eventually as blackened sclerotia in the husks of the florets, Ergot contains toxic alkaloids. The name is a reference to The Brothers of St.

Anthony, who developed treatments for victims of this ailment, and to the burning sensation in limbs resulting from eating Ergot-infected cereals. Distribution Although widely distributed on wild grasses throughout Britain and Ireland as well as mainland Europe, North America and many other parts of the world, Ergot infection of cereal crops is normally kept to the required low level by appropriate farm management. This entails planting ergot-free seed and ploughing the land after harvest in order to bury crop residues and reduce the chance of ergot spores germinating in the following spring.

Crops can be cleaned of ergot and must be if for human consumption , but this is an expensive process and so infected grain has a much-reduced sale price. Taxonomic history The basionym of this ascomycete fungus dates from , when Swedish mycologist Elias Magnus Fries described this species and gave it the scientific name Cordyceps purpurea. Synonynms of Claviceps purpurea include Cordyceps microcephala Wallr.

Etymology The origin of the generic name Claviceps is the Latin noun clava meaning a club, with the suffix -ceps meaning head - hence club-head fungus. As you might expect, purpurea is a reference to the dark purple colour of the sclerotia. Identification guide Sclerotia The sclerotia pictured above and left on a foxtail grass flowerhead are banana-shaped; purple, becoming black; 1 to 2mm dia.

Spore colour Creamy-white. Rye and ryegrasses are particularly susceptible to this fungal infection. Season April to September in Britain and Ireland. Similar species The common name Ergot refers to many similar ascomycete fungi of the family Clavicipitaceae. Dennis, R. Breitenbach, J.

Fungi of Switzerland. Volume 1: Ascomycetes. Verlag Mykologia: Luzern, Switzerland. Medardi, G. Centro Studi Micologici: Trento. Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J.

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Claviceps purpurea: características, ciclo de vida, hábitat, enfermedades

Claviceps purpurea var. Their lifecycles are complex. The sclerotia develop in place of the seeds once spores of a Claviceps fungus have infected grass flowers. Ryegrass is particularly susceptible because of its open flower form. The Ergot mycelium then destroys the flower ovary and ultimately produces vast numbers of conidia asexual spores that can infect grass florets. Ergot infects only the ovary of cereal and grass plants; other part of the plant are unaffected.

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Ergot : the genus Claviceps

Este cornezuelo es una estructura de supervivencia que puede permanecer durante mucho tiempo en dormancia. Cuando las condiciones ambientales son adecuadas, se forma el esclerocio que puede producir uno o varios estromas. En estos peritecios se encuentran los ascos o estructuras formadores de ascosporas. Las ascosporas van a ser liberadas al aire por medio de unos orificios en las cabezuelas que son denominados ostiolos y trasportadas por los vientos.

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Ergot the Genus Claviceps PDF

Epidemiology[ edit ] Claviceps purpurea has been known to mankind for a long time, and its appearance has been linked to extremely cold winters that were followed by rainy springs. Sclerotia germinate in spring after a period of low temperature. Water before the cold period is also necessary. Monks of the order of St.

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The infection process mimics a pollen grain growing into an ovary during fertilization. Because infection requires access of the fungal spore to the stigma, plants infected by Claviceps are mainly outcrossing species with open flowers, such as rye Secale cereale and ryegrasses genus Lolium. The proliferating fungal mycelium then destroys the plant ovary and connects with the vascular bundle originally intended for seed nutrition. The first stage of ergot infection manifests itself as a white soft tissue known as sphacelia producing sugary honeydew, which often drops out of the infected grass florets. This honeydew contains millions of asexual spores conidia which are dispersed to other florets by insects.

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