title: External ultrastructure of fruit body initiation in Morchella.
abstract: The external morphological changes occurring during initiation and early stages of fruit body development of a Morchella sp., before the development of asci, were examined by scanning electron microscopy. Four stages of primordial development were distinguished. First, disk-shaped knots of 0.5-1.5 mm were observed on the surface of the substrate. Next, the knot inflated and a primordial stem emerged from its centre. Afterward, the stem lengthened, oriented upward, and two types of hyphal elements developed: long, straight and smooth basal hairy hyphae and short stem hyphae, some of which were inflated and projected out of a cohesive layer of tightly packed hyphal elements. Finally, when the stem was 2-3 mm long, pre-apothecia emerged in the apical end, with ridges and pits having distinguished types of paraphyses. Extracelluar mucilage covered the ridge layer and helped give the tissue its shape and rigidity.
authors.affiliation: MIGAL, Galilee Technology Centre, POB 831, Kiryat Shmona 11016, Israel. segula@migal.org.il
authors.forename: Segula
authors.initials: S
authors.lastname: Masaphy
mesh_terms: D001203:Ascomycota / Q000502:physiology / Q000648:ultrastructure*; D048690:Fruiting Bodies, Fungal / Q000648:ultrastructure*; D025301:Hyphae / Q000502:physiology / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning