Spore Discharge in Basidiomycetes: III. Spore Liberation from Narrow Hymenial Tubes

The hymenial tubes of Polyporus betulinus were shown to be approximatelycylindrical,and to have a sporulating hymenium over the greater part oftheir surface. Sporophores were tilted through measured anglesfrom the vertical in the field and in the laboratory, and theeffect on spore liberation was measured by determining the numberof spores liberated from particular tubes in standard time.All tilting caused a reduction in spore liberation. The amountof this reduction was found to compare closely with that predictedfrom calculation of the amount of hymenium lying directly abovethe orifice at various angles of tilt. It is therefore concludedthat liberation from the tube can be accounted for by the initialviolent discharge of the spore and gravitational attractionalone. An addendum corrects an earlier paper (1959) in thisseries. It shows that the variation in density of spore depositscollected from Trametes gibbosa was due to air currents in theapparatus, not to variation in sporulation rate.     

Characterization of microsatellite loci in silver carp (Hypophthalmichthys molitrix), and cross‐amplification in other cyprinid species

Captive populations of silver carp (Hypophthalmichthys molitrix), a major aquaculture species in Asia, would undoubtedly benefit from genetic monitoring and improvement programs. We report the isolation and preliminary characterization of 16 microsatellite loci derived from both conventional and microsatellite‐enriched libraries. Inheritance studies confirmed the allelic nature of observed polymorphisms at all loci, while identifying null alleles at two loci. These loci, having varying degrees of polymorphism, should provide useful markers for applied genetic studies. A high degree of cross‐amplification among 10 other cyprinid species suggests that these loci may have more widespread utility.     

The Measurement of Electrostatic Charges on Spores of Merulis lacrymans (Wulf.) Fr.

Spores of Merulius lacrymans were allowed to fall through ameasured horizontal electric field. The distance of displacementfrom vertical fall gave a measureof the charge/mass ratio ofthe spores. The mass of a ‘mean’ spore was measuredby direct weighing, and calculation then gave a negative electrostaticcharge on a ‘mean’ spore as (i.35±o.12) x10^–8 e.s.u. It is shown that a charge of this order ofsize can exert no significant effect on the movement of thespores in relation to the hymenial surfaces.     

Spore Discharge in the Basidiomycetes: I. Periodicity of Spore Discharge by Trametes gibbosa Fr.

Variations in the rates of spore discharge from this fungushave been examined in controlled laboratory conditions, usingapparatus designed to make a continuous record of the numbersof spores discharged by a strip of hymenium measuring approximately4.5 cm. X o.1 cm. These records have been extended by a directmicroscopic study of the numbers of spores falling through asmall area below the hymenium during successive short periods. Analysis of the continuous record has shown that at any onetime the rate of spore discharge is not uniform over the wholehymenium, and that at any one site it ia not constant. The variationin the rate of discharge in any one site is rhythmical, withintervals of the order of 30 to 90 minutes between maxima. Thesmall linear areas of hymenium which have been examined haveshown nearly the same rhythm-overall, but the phase of thisrhythm has differed at different sites in the area.