Photographic analysis of field-monitored fern gametophyte development and response to environmental stress.

Premise: Ferns differ from seed plants in possessing a life cycle that includes a small, free-living, seemingly vulnerable gametophyte stage in which sexual reproduction occurs. Most research on the response of fern gametophytes to environmental stress has been conducted on gametophytes grown in culture or harvested from natural habitats and subsequently manipulated and tested in laboratory experiments. We present a fixed-distance photographic methodology for monitoring longevity of gametophytes and their response to environmental stress in natural, undisturbed habitats over their life spans.

Alpine ecology, plant biodiversity and photosynthetic performance of marker plants in a nitrogen gradient induced by Alnus bushes.

Background: Alpine alder vegetation acts upon the nearby grass and dwarf shrub vegetation by the nitrogen supply from the symbiotic bacteria Frankia alni of Alnus viridis. This has been studied in two transects concerning plant distribution, plant diversity, nitrate concentration in soil and photosynthetic performance of specific marker plants.

Results: Away from the alder stand, a band of some meters was dominated by Calamagrostis varia which then was followed by alpine dwarf shrub vegetation.

Bryophyte diaspore bank: a genetic memory? Genetic structure and genetic diversity of surface populations and diaspore bank in the liverwort Mannia fragrans (Aytoniaceae).

Propagule banks are assumed to be able to store considerable genetic variability. Bryophyte populations are expected to rely more heavily on stored propagules than those of seed plants due to the vulnerability of the haploid gametophyte. This reliance has important implications for the genetic structure and evolutionary potential of surface populations.

Multilocus dataset reveals demographic histories of two peat mosses in Europe.

Background: Revealing the past and present demographic history of populations is of high importance to evaluate the conservation status of species. Demographic data can be obtained by direct monitoring or by analysing data of historical and recent collections. Although these methods provide the most detailed information they are very time consuming.

Patterns of variation of a common fern (Athyrium filix-femina; Woodsiaceae): population structure along and between altitudinal gradients.

Genetic variability of Athyrium filix-femina populations was evaluated with regard to phenotypic, allozyme, and RAPD variation in 20 Swiss populations along five altitudinal gradients at four different elevations in the northern Swiss Alps. Additionally, allozyme and phenotypic variations in one Italian and two Spanish populations were compared with the variation in the Swiss populations. We hypothesized that there will be statistically significant genetic differences among populations of different altitudes and sites.

Large clones on cliff faces: expanding by rhizomes through crevices.

Background And Aims: Large clones of rhizomatous plants are found in many habitats, but little is known about whether such clones also occur on cliff faces where environmental conditions are extremely harsh and heterogeneous.

Methods: Using molecular (intersimple sequence repeat, ISSR) markers, the genotypic composition of a cliff-face population of Oxyria sinensis in Sichuan, China, was investigated.

Key Results: The 98 O.

Contrasting phylogeographic patterns in Sphagnum fimbriatum and Sphagnum squarrosum (Bryophyta, Sphagnopsida) in Europe.

The chloroplast phylogeography of two peat mosses (Sphagnum fimbriatum and Sphagnum squarrosum) with similar distributions but different life history characteristics was investigated in Europe. Our main aim was to test whether similar distributions reflect similar phylogeographic and phylodemographic processes. Accessions covering the European distributions of the species were collected and approx.

Allelic configuration and polysomic inheritance of highly variable microsatellites in tetraploid gynodioecious Thymus praecox agg.

Polyploidy plays a pivotal role in plant evolution. However, polyploids with polysomic inheritance have hitherto been severely underrepresented in plant population genetic studies, mainly due to a lack of appropriate molecular genetic markers. Here we report the establishment and experimental validation of six fully informative microsatellite markers in tetraploid gynodioecious Thymus praecox agg.

Isozyme variability of the wetland specialist Swertia perennis (Gentianaceae) in relation to habitat size, isolation, and plant fitness.

We examined the effects of size and spatial isolation of fens on the isozyme variability of 17 populations of Swertia perennis. This long-lived perennial is a locally abundant fen specialist in Switzerland, where wetlands have been strongly fragmented. Isozyme variability was comparable to other outcrossing plants (A = 1.

Estimation of the relative importance of sexual and vegetative reproduction in the clonal woodland herb Anemone nemorosa.

Anemone nemorosa is a perennial rhizomatous plant of European woodlands. The "probability of clonal identity" method estimated the relative proportion of sexual to vegetative reproduction in this species to be 4.4% from allozyme genotype distributions.