A study of genetic variation in the threatened hepatic Petalophyllum ralfsii (Wils.) Nees. and Gottsche (Fossombroniaceae)

Genetic diversity of the dioicous thallosehepatic Petalophyllum ralfsii wasinvestigated and its significance for thespecies' conservation assessed. This globallythreatened hepatic apparently reaches itsgreatest abundance in the British Isles.Samples were taken from throughout the Britishrange; 178 individual thalli from 24 coloniesin nine localities were scored for variation in11 enzyme systems and 16 putative loci. Novariation was observed. Many studiesdemonstrating allozymic monomorphism inbryophytes have been of bisexual, orpredominantly vegetatively propagating taxa.Lack of variability in an obligatelyoutbreeding taxon, with no specialisedvegetative dispersal mechanism, lends supportto the view that hepatic taxa, at least withinEurope, routinely support little allozymicvariation. Unlike flowering plants, lifehistory and breeding system do not appear tohave significant effects on the extent andpartitioning of allozymic diversity.     

Spatial Distribution and Reproductive Behaviour of a Triploid Braken (Pteridium aquilinum) Clone in Britain

Chromosome counts of 156 in root tip cells of a bracken plantgrowing in a natural British population confirm the first recordof a triploid in this species. Spore and stomatal measurementssupport the contention of earlier work that cell size in correlatedwith ploidy level in ferns, but the plant is unusual in comparisonwith other odd-numbered polyploids in its degree in its of fertility('good' spore and functional gametophyte production). Two-dimensionalmapping based on isozyme electrophoresis reveal substantialspatial dimensions for the triploid, indicating a plant of considerableantiquity.Copyright 1993, 1999 Academic Press Pteridium aquilinum, bracken, triploid, clone, reproduction, spatial distribution, genetics     

Branched-chain amino acid aminotransferase activity in the tissues of lake trout

The enzyme branched-chain amino acid aminotransferase (BCAT) was found in five tissues of fingerling lake trout, Salvelinus namaycush, (listed in order of decreasing tissue specific activity): posterior kidney, skeletal muscle, gill, liver, and anterior kidney. This pattern is consistent with that found in other animals. The results of this study seem to indicate that BCAT in the liver of lake trout has a higher specific activity than that of the rat and that the specific activity is higher in both the liver and skeletal muscle than it is in these organs of the chick.