Phylum: Ascomycota

The largest division of fungi, many are parasite on plant and others are saprobic live on soil or on decaying materials. the distinguishing characteristic of all it^'s  members is the ascus (pl. asci), a sac-like cell in which meiosis and karyogamy (nuclear division) occur and within which the resulting meiospores (specifically called ascospores) develop, during sexual reproduction. The number of ascospores formed is usually constant and typically 8. In the large majority the asci are elongated, either club- shaped or cylindrical.,

 One of the most important features of ascus morphology, now proposed as the basis for classification of Ascomycota  is the structure of ascus wall. In general two types of asci are recognized: the unitunicate and bitunicate, Unitunicate asci have a single wall. Some have a built-in lid or operculum Other asci have no operculum.

The fruiting bodies that make and hold the asci are called ascocarps.

Ascocarp can be divided into five main types:

1. Cleistothecium (pl. cleistothecia) which is globose (roughly spherical) and has no opening. They are typically black when mature.

2. Perithecium is a flask shaped structure with an opening (ostiole) at the top through which the ascospores escape.

3. Apothecium is a cup or saucer shaped structure with the asci exposed on the surface.

4. Pseudothecium resembles a perithecium, but it develops differently, and forms bitunicate (double walled) asci.

5. Naked or free asci have no ascocarp.

Sexual reproduction is heterothallic, the most common of these are Gametangial copulation, Gametangial contact, Spermatization and Somatogamy.

Asexual reproduction is common, by means of Fission, Budding, Fragmentation and Conidia which are borne on specialized hyphae called conidiophores.

 Ascomycota hyphae are septate with chitinous cell wall and with regular cross-walls called septa (centrally perforated to allow movement of cytoplasm, and sometimes nuclei, between compartments), many yeasts are unicellular, so don't produce hyphae).

مواضيع ذات صلة

الفيومونيسينات Fumonisins

جنس Aspergillus

SUBCUTANEOUS MYCOSES

FUNGAL TOXINS & ALLERGIES

سموم ستريوفيريدين Citreoviridin المنتجة بواسطة فطر Penicillium

مكافحة السموم الفطرية

تأثير الفطريات والسموم الفطرية على الدواجن

مؤثرات وأضرار بعض السموم الفطرية

التسمم الفطري Mycotoxicosis

فطر الخميرة

Candidiasis (candidosis)

التسمم الميسيلي ( mycetism)