Primary basidiospore charge and taxonomy of Agaricomycetes

Abstract

This article deals with the polarity of electrostatic charges that are carried on ballistic basidiospores after their liberation from fruiting bodies. The spores were collected by placing a portable device beneath the basidiome and allowing them to fall in a horizontal homogeneous electrostatic field, created by vertical parallel plane electrodes. Thus, the experimental setup enabled to investigate the primary charges, the charges present on spores immediately after the release from spore bearing cells. Spores of 135 basidiomes of 50 species of hymenomycetous fungi were collected in various natural conditions. The non-turgescent (drying up, collapsing or ceasing to sporulate) basidiomes were excluded from the taxonomical analysis; the 128 turgescent basidiomes (223 spore samples) of 47 species were taxonomically analyzed. These species represented eight orders (Agaricomycetes, Basidiomycota), covering 21 families and 36 genera. The analysis showed that the spore charges were distributed according to the polarity similarly in all samples in a species, and in a genus. In most cases also genera of one family had the same type of polarity distribution of spore charges. Possibly all taxa from species to monophyletic families are characterized by specific type of polarity of the primary electrostatic charge of basidiospores. Depending on the taxonomical group, all spore charges were negative, positive, or both negative and positive charges were present. This information could be useful in investing the ballistosporic discharge mechanism and for constructing higher-level phylogeny.

Bulk isolation of basidiospores from wild mushrooms by electrostatic attraction with low risk of microbial contaminations

“…The only four exceptions of fleshy mushrooms which failed in spore collection in our experiments were single mature individuals of Hygrocybe virginea and Hygrophorus eburneus (both Hygrophoraceae ), Lepista saeva ( Tricholomataceae ) and Rickenella fibula ( Repetobasidiaceae ). Since other species of the same or a closely related family gave spores in the lids (Table 2 ), these four failures did not relate to any specific taxonomic position of mushrooms but possibly to that spore shedding ended by fruiting body age (Haard and Kramer 1970 ; Li 2005 ; Saar and Parmasto 2014 ; not further analysed).…”

“…Attraction between higher up-flying spores and the plastic lids might be expected to be stronger than between less far up-flying spores and the lids. Basidiospores do also have electric charges (Buller 1909 , 1922 ; Gregory 1957 ; Swinbank et al 1964 ; Webster et al 1988 ; Saar 2013 ; Saar and Parmasto 2014 ; Saar and Salm 2014 ). Individual differences in charging of spores remain as explanation for the observations.…”

“…Charges of endogenous origin are possibly connected to the mass transfer when Buller’s drop suddenly fuses with the liquid film on the adaxial side of a spore. In addition, airflow will create charges on spores by triboelectric effects (Buller 1909 ; Webster et al 1988 ; Saar and Parmasto 2014 ; Saar and Salm 2014 ) which could give an extra stimulus to the spores to leave the caps against gravity by electrostatic attraction to plastic lids.…”

“…The charges cause in horizontal electric fields that spores shed from mushrooms will drift away to one side. In many species, there are populations of positively and of negatively charged spores, while spores in some species are unipolar-positively and in some others unipolar-negatively charged (Buller 1922 ; Gregory 1957 ; Webster et al 1988 ; Saar 2013 ; Saar and Parmasto 2014 ; Saar and Salm 2014 ). Of the species that we tested in this study (Table 2 ), absolute charges of basidiospores have been estimated before for A. campestris in different experimental series between 1.55/0.39/0.39 and 3.10/3.11/2.16 × 10 −17 C (mean 2.23/1.28/0.93 × 10 −17 C), for C. micaceus between 0.85 and 4.22 × 10 −17 C (mean 2.14 × 10 −17 C), for L. nuda 1.88 × 10 −17 C, for M. oreades between 1.25 and 10.12 × 10 −17 C (mean 4.37 × 10 −17 C), for two Pholiota spec.…”

“…These authors concluded from own and literature data for 43 species, 33 genera, 23–25 families and 9 orders of the Agaricomycetes that their ballistospores exhibit electric loads. While we used in our studies in the majority species of the Agaricales and to less extend species from the Boletales and other orders (Table 2 ), Saar and colleagues analysed the electric properties of larger species ranges of Polyporales and Boletales with poroid hymenia, in addition to species from the Agaricales , Russulales and others (Saar 2013 ; Saar and Parmasto 2014 ; Saar and Salm 2014 ). Considering shared species between the different studies, evidence for ballistospore electric charging is now available for over 100 different species (i.e.…”