Cross-fertilisation in the monoecious Pellia borealis, n = 18, and spatial distribution of two peroxidase genotypes

Abstract

A population of Pellia borealis, n = 18, from Diabli Skok reservation (north west Poland) is polymorphic with respect to two peroxidase alleles PX 1b and PX 2" (63 and 37 per cent respectively), the spatial distributions of which are non-random. Thalli growing in a close neighbourhood exhibit only one of the two mutually excluding alleles, as shown by analysis of 54 samples, thus pointing to intense vegetative reproduction of thalli within individual samples. The clonal structure extends beyond the area of the sample and frequently includes the whole carpet of P. borealis. Apart from intense vegetative reproduction, differential selective value of thalli may constitute another factor shaping clonal structure of samples and carpets.Thirty-eight out of 40 analysed progenies were found to be monomorphic with respect to PX I" and PX 2" alleles. Sporangia from which these progenies were obtained have been collected from monomorphic samples of corresponding PX 1" and PX 2" phenotypes. The results are interpreted as reflecting seif-fertilisation and contrast with earlier data on high frequency of cross-fertilisation noted in P. epiphylla, n =9.

Clonal structure and fertility in a sympatric population of the peat mosses Sphagnum rubellum and Sphagnum capillifolium

“…A mixed mating system, with roughly 80% self-fertilization, is indicated here under the assumption that progenies with the maternal genotypes were self-fertilized rather than fertilized by males with the same set of alleles. This result resembles the estimates of 5 and 25% outcrossing for Pellia epiphylla (L.) Corda and Pellia borealis Lorbeer (Zielinski 1986), the only bisexual bryophytes previously investigated. The fact that colonies of bisexual peat mosses frequently produce abundant spore capsules and occupy habitats subjected to continual disturbance was previously taken as an indication that they have a potential for selffertilization (Cronberg 1993).…”

Population genetics of the moss Plagiothecium undulatum (Hedw.) Schimp. I. Inheritance of allozymes

“…Similar results for one enzyme system were obtained in liverworts by Zielinsky (1984Zielinsky ( , 1986. In order to estimate the outcrossing rates in the monoecious Pellia epiphylla (Zielinsky, 1984) P. borealis (Zielinsky, 1986) he analysed the progenies from different sporangia for peroxidase. A 1:1 segregation of two peroxidase phenotypes was observed in progenies from sporangia which were the results of (demonstrable) cross-fertilizations.…”

Chromosomes as indicators of bryophyte reproductive performance

“…A single act of selfing in bryophytes would be tantamount to asexual reproduction but the evolution of dioecy has effectively overcome this problem in many species. However, there is also strong evidence of the occurrence of outcrossing within monoecious species (Anderson & Lemmon, 1974;Longton, 1976Longton, , 1982Zielinski, 1984Zielinski, , 1986.…”

“…For studies of the sort required, modern chromosome banding techniques offer a degree of precision that has been hitherto unattainable. Coupled with isoenzyme analyses, which are highly pertinent and are beginning to be exploited in this context (Zielinski, 1984(Zielinski, , 1986, the topic is now one of great promise.…”