Emission rate of charged spores in basidiomycetous fungi and the relaxation time of their electric charges

Basidiospores are one of the main components of coarse fraction of atmospheric aerosol. Majority of them, the ballistospores of 20,000 species of Basidiomycotina, carry electrostatic charges when getting airborne. To study the polarity and magnitude of primary charges and the hymenial emission rate of charged spores, 128 spore samples of 31 species of Agaricomycetes were collected in natural conditions. A portable device was placed under the fruiting body and the freely falling charged spores were extracted from the air by a horizontal homogeneous electrostatic field. The charge polarity distribution was the same in all intraspecies spore samples; it was unipolar-positive, unipolar-negative, or bipolar, depending on the species. The mean spore charge magnitude was 21–981 e, and it was not related to the emission rate of charged spores. The hymenial emission rate was fluctuating, and the maximum value was 715 charged spores cm^?2 s^?1. To estimate the territorial emission rate of charged spores, area of the hymenial surface per hectare of forest was calculated for three species and the maximum values were 11 m² ha^?1 and 8.6 × 10⁷ charged spores ha^?1 s^?1. Calculations showed that a spore charge diminished sevenfold within 47 min. Ecologists, health and agricultural scientists could be interested in this information. It could be useful by investigating the role of microorganisms in meteorological phenomena and in atmospheric processes in general.     

High resolution optical spectra in vivo: Photoactive protochlorophyllide in etiolated leaves at 5 K

We describe here high-resolution spectra of etiolated leaves studied by means of selective monochromatic excitation of fluorescence as well as by hole-burning technique at liquid helium temperature. Up to now site selection spectroscopy has not been successfully applied to biologically active chromophores in vivo. Our results demonstrate that even in the presence of specific pigment-protein and pigment-pigment interactions very narrow purely electronic lines can be obtained in the optical spectra of biological systems.