Pilar Díez de Revenga Torres

Persistence of basidiospores and sclerotia of ectomycorrhizal fungi and Morchella in soil

Locations of epigeous basidiocarps of five common ectomycorrhizal fungi with substantial spore deposits beneath them and of two hypogeous species were marked in the fall. Subsamples of the litter a...

Changes and effects of a natural fire on ectomycorrhizal inoculum potential of soil in a Pinus halepensis forest

Abstract A typically mediterranean forest of Pinus halepensis wass tudied. During two years following fruiting fungal species, the number of sclerotia in soil, and the percentages and types of mycorrhizas present were determined. In burned stands ascomycetes were typical carbonicolous while basidiomycetes were strongly reduced. The sclerotia extracted from soils were mainly Cenococcum . The number of sclerotia in burned stands was greater than in unburned stands. Seven types of mycorrhizas were recognized in Pinus halepensis root systems from bioassays: Cenococcum , E-strain, Rhizopogon, Suillus, Tuber, Xerocomus , and one non-identified. Nearly 100% of the roots were colonized by mycorrhizal fungi. Ectendomycorrhizas represented 50–90% of the total number. The predominant type is ectendomycorrhizas formed by ascomycetes included in the E-strain group.

Basidiospore viability and germination in ectomycorrhizal and saprotrophic basidiomycetes

Spores of the ectomycorrhizal basidiomycetes Rhizopogon rubescens and Suillus tomentosus were induced to germinate and stained with fluorescent stains FDA and DAPI to assess germinability and viability. Basidiospores of several saprotrophic species including Pleurotus ostreatus, Marasmius oreades, Agaricus brunnescens, Coprinus quadrifidus and Conocybe lactea were also assayed for comparison. Nearly all spores of both the ectomycorrhizal and saprotrophic fungi contained intact nuclei. The percentage of R. rubescens and S. tomentosus spores that stained with FDA increased throughout the study. Peaks in FDA staining corresponded with germination events which occurred every 9 to 13 days. The FDA staining in spores of P. ostreatus and M. oreades was high and corresponded with high rates of germinability. Germination and FDA staining of the other saprotrophic species were variable. In ectomycorrhizal and several saprotrophic species FDA staining was unreliable as an indicator of viability but served as a good predictor of dormancy. Non-fluorescent vital and nuclear stains were compared with the fluorescent stains and gave similar results. Equations for estimating viability, dormancy, and activation of spores are presented.

Basidiospore viability in stored slurries

The viability and activity of basidiospores corresponding to 14 species of ectomycorrhizal fungi stored in slurries was studied. The methods used were the aceto-iron-haematoxylin nuclear stain to determine basidiospore viability and the FDA stain to determine basidiospore activity and dormancy. The basidiospores of Cortinarius sp., Hebeloma sp., Inocybe sp., Laccaria bicolor, Laccaria laccata, Lactarius deliciosus, Lactarius sanguifluus, Rhizopogon roseolus, Russula delica, Russula sanguinea, Suillus collinitus, Suillus granulatus, Suillus variegatus and Tricholoma terreum were suspended in slurries in duplicate experiments and half were stored at 3–4 °C and the other half at −15°. Spore viability and activity was tested after 180 days of storage. Loss of viability was least in species of Rhizopogon and Suillus , but data showed an almost total loss of viability in both refrigerated and frozen slurries of all fungi.

Preocupaciones lingüísticas y mecanismos léxicos en la obra de Guillermo Bowles "Introducción a la historia natural, y a la geografía física de España"

En el presente trabajo estudiamos los mecanismos linguisticos de la lengua de la ciencia del siglo XVIII a traves del primer texto redactado originalmente en espanol sobre Historia Natural. En esta obra, escrita por Guillermo Bowles, se advierte la preocupacion linguistica existente en el ambito de la ciencia a la hora de definir los terminos referentes a las realidades de los tres ambitos del Reino Natural. Asi mismo, se localizan variantes diatopicas y diastraticas y procesos de definicion que ponen de manifiesto la importancia de estos textos para la Historia de la Lengua Espanola y la Historia de la Ciencia.