Search results
Results from the WOW.Com Content Network
However, asci in some genera or species can occur in numbers of one (e.g. Monosporascus cannonballus), two, four, or multiples of four. In a few cases, the ascospores can bud off conidia that may fill the asci (e.g. Tympanis ) with hundreds of conidia, or the ascospores may fragment, e.g. some Cordyceps , also filling the asci with smaller cells.
Original - The asci and ascospores of Morchella elata. The total field of view is 218 X 164 µm. Reason A high quality image of the microscopic features of fungi, taken with high quality equipment. This sort of image is hard to come by, and having such a high quality and freely licensed image is brilliant. The image is already featured on Commons.
As an ascomycete, Ceratocystis coerulescens produces ascospores encased as groups of eight in asci. The asci are protected by a perithecium, a flask-shaped ascocarp, in which the pathogen overwinters. Ascospores are the sexual spores and are far less common than the asexual spores known as conidia.
The eight ascospores are produced inside an ascus. Sordaria squashes can give us information about crossing over during meiosis. If no crossing over occurs a 4:4 pattern is produced: four black spores, and four tan spores all lined up. If crossing over does occur there is a 2:2:2:2 pattern visible, or a 2:4:2 pattern.
The paraphyses are abundant, hyaline (transparent or glass-like), persistent. The asci are 8-spored, unitunicate, pedicellate, persistent, with a J+ or J−, apical ring. Ascospores hyaline, multi-septate, often guttulate, lacking any mucilaginous sheath or appendages. The asexual morph was undetermined (as of March 2021). [10]
The defining feature of this fungal group is the "ascus" (from Ancient Greek ἀσκός (askós) 'sac, wineskin'), a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of Ascomycota are asexual and thus do not form asci or ascospores.
The asci are globose, deliquescent, and scattered throughout the interior cavity i.e. as in Eurotium or arising in tufts from the basal region of ascocarps as in Erysiphe. In this case the ascocarp is round with the hymenium enclosed, so the spores do not automatically get released, and fungi with cleistothecia have had to develop new ...
The bitunicate asci are thick-walled, with an outer and inner layer. The outer and inner layer of the ascus wall are called exotunica and endotunica, and they separate during ascospore release. [6] The asci usually contains eight ascospores, while the shape and separation of the ascospores are more variating. [13]