The mycologist最新文献

The extraradical mycelium of ectomycorrhizas is comprised of a network of hyphae that may initiate rhizomorphs, sclerotia and sexual reproductive structures. The development of these structures requires photosynthates produced by host trees. In this study, the initiation and early development of Laccaria bicolor (Maire) Orton fruitbodies (basidiocarps) were studied. Seedlings of Pinus resinosa Ait. and Pinus sylvestris L. were colonized by L. bicolor, a broad host epigeous ectomycorrhizal basidiomycetous fungal species, in growth pouches. Ectomycorrhizas with an extensive extraradical mycelium formed on short roots within 7-12 days after fungal inoculum was introduced. Numerous sites of hyphal aggregation, many of which subsequently developed into basidiocarp primordia, were initiated in the extraradical mycelium. Initial changes in aggregating hyphae included swelling and branching followed by growth of hyphae perpendicular to the paper wick in growth pouches. A stipe and a pileus primordium developed but none of these basidiocarp primordia matured. Distinct regions were evident in the stipe and pileus when sections were stained by various methods. Loose hyphae at the apex and periphery of the pileus were separated by mucilage. In Petri dishes with vermiculite as the substrate, basidiocarps of Laccaria laccata formed in ectomycorrhizal associations with Pinus sylvestris, developed a mature pileus with an hymenium and mature basidiospores.

A method is described which allows the diversity of agarics in a site to be determined as an index, the Site Diversity Index (SDI). For this the individual species recorded from a site are given a score which is that of the frequency of recording class to which it has been assigned, that score increasing with increased rarity of recording in the BMS database. The methods of defining the classes of frequency of recording, the score accorded to a class, and the calculation of the SDI are described. Examples of the SDI are given for several sites in the Forest of Dean as well as for other sites and areas. Site Profiles illustrate the extent to which each of the classes has been completed. The flattening of the rate of accumulation of species is discussed. Further progress will involve the widening of the range of included species to those of other classes of basidiomycetes. The method can be used to rank sites and, in the early stages of a survey and given the meeting of two criteria, to prediction of future diversity of a site. Further use in respect of Important Fungus Areas and conservation sites is envisaged.

Zymography is an electrophoretic technique by which enzyme activity can be visualized directly on a polyacrylamide gel as discrete bands. A modified, more rapid technique for amylase zymography is described and compared with previously published methods. Whereas previous methods are based on 0.1 M acetate buffer as substrate buffer, our method utilizes 50mM Tris buffer containing Ca²⁺, Na⁺, NaN³ and Triton X-100 which helps rapid hydrolysis of the starch and stabilization of the enzyme. The staining procedure, previously requiring overnight incubation of the gel in iodine solution at 4°C, has been reduced to 5 min at room temperature. Both methods gave rise to comparable levels of enzyme activity on polyacrylamide gels. Our modified method requires 8 h to complete the whole zymographical procedure instead of 18-20 h as in previous methods.