Zur Keimungsbiologie ausgewählter Xerothermrasenarten - Teil 2: Caryophyllaceae

Abstract

Partzsch, M.: Germination biology of xerothermic grassland species - Part 2: Caryophyllaceae. - HercyniaN. F. 44 (2011): 127 – 144.Nowadays, in the focus of vegetation ecology stand experimental attempts on restoration of grasslands,for which the knowledge on germination biology is very important in order to evaluate the success ofestablishment of the introduced species. The series of articles of germination biology of different speciesintroduced here, should close gaps in the present state of knowledge as well as provide assistance bythe assessment or with the choice of the species. In the present study eight species of Caryophyllaceae(Dianthus carthusianorum, Gypsophila fastigiata, Lychnis viscaria, Petrorhagia prolifera, Scleranthusperennis, Silene nutans, S. otites, S. vulgaris) were chosen usually occurring in open xerothermic vegetationunits. In order to identify optimal germination conditions, experiments were carried out underthree different temperature-light regimes (8 / 4 °C, 20 / 10 °C, 32 / 20 °C; 12 h light : 12 h darkness; 45days). The collected seeds were divided in two parts. The first germination experiment was carried outca. 4 weeks after collection. The other diaspores were buried in soil from November till March, to ensurehibernation until the next experimental phase in following spring. Seed viability was tested before andafter the experiments.Results indicated that seeds of six out of eight species were not dormant, whereas Scleranthus perennisand Silene otites showed partially dormancy. In general, the species germinated in a broad range oftemperature during first experiment and after hibernation: Dianthus carthusianorum germinated wellunder cold and warm conditions and Gypsophila fastigiata, Lychnis viscaria and Petrorhagia proliferaunder warm and hot conditions. Silene otites germinated generally low. Otherwise, Scleranthus perennis,Silene nutans and S. vulgaris showed the optimal germination temperature at 20 / 10 °C. The germinationbehaviour of Scleranthus perennis and Silene otites is characterised as asynchronous germination,meaning that, even under favourable conditions, only a proportion of seeds germinates in a certaintime. In generally, the natural cold stratification (hibernation) did not lead to an enhanced germination.There was found slightly negative, but not significant correlations between seed size and germinationbehaviour.Results regarding the germination behaviour and seed viability allow ranging Caryophyllaceae speciesin two diaspore bank types: (1) the more transient type: Dianthus carthusianorum, Gypsophila fastigiata,Lychnis viscaria, Petrorhagia prolifera, Silene nutans and Silene vulgaris and (2) the long-term persistenttype: Scleranthus perennis. The type of Silene otites was not fully clear.