Search

Spontaneous hybrids between alien and native plant species are alien taxa and they threaten native biodiversity due to their high competitive ability or introgression. Thus, we tested the effect of soil conditions, elevation and type of ramet clusters (clonal clumps of shoots) on sexual and asexual ramets of Solidago xniederederi, a hybrid between the invasive alien S. canadensis and the native S. virgaurea. We also tested the relationships between the size of sexual ramets and habitat conditions in the hybrid and its parental species, based on ten sites in NE and S Poland, respectively. The hybrid and its parental species occurred on mineral soils with a wide range of textures (sand, loamy sand, sandy loam, silty loam and loam) and pH (from strongly acidic to slightly alkaline). Sexual ramet clusters dominated in S. xniederederi populations, while the total number of ramets was highest in mixed ramet clusters. The cluster x site interaction had a significant effect on the length and biomass of sexual ramets in hybrid populations. Moreover, we found a significant effect of the taxon x site interaction in the case of biomass of sexual ramets and synflorescences (capitula arranged in panicles). Based on the biomass of sexual shoots and synflorescences, the competitive abilities of the hybrid may be more or less similar to S. canadensis or S. virgaurea albeit depending on site conditions. [ABSTRACT FROM AUTHOR]

In this study, we focused on the potential production of descendant ramets in sexual, asexual, and mixed ramet clusters of Solidago ×niederederi Khek (Asteraceae), a natural hybrid between the North American S. canadensis and the European S. virgaurea. We selected eight populations of the hybrid occurring in southern Poland. The ANOVA results proved the significant effect of cluster type and population on the number of descendant ramets in sexual, asexual, and mixed ramet clusters. The post-hoc Tukey test showed that the number of descendant ramets in sexual and mixed ramet clusters differs significantly (p < 0.001). The number of descendant ramets was positively correlated with the number of maternal ramets in sexual, asexual, and mixed ramet clusters, reaching the coefficient values of 0.78, 0.64, and 0.82, respectively. Moreover, the number of descendant ramets was positively correlated with the height of maternal ramets in mixed ramet clusters, reaching the coefficient value of 0.25. The post-hoc Tukey test revealed the significant differences between the height of ramets originating from sexual and asexual ramet clusters (p < 0.001). Our results complemented the current state of knowledge and brought evidence that the number of descendant ramets might be influenced by a type of ramet cluster. [ABSTRACT FROM AUTHOR]

In this paper, we present preliminary results from the study on the effect of fruit storage period on seed germination in Solidago ×niederederi and its parental species (S. canadensis and S. virgaurea). We aimed to test the hypothesis that a long fruit storage period (i) reduces the final percentage and speed of seed germination, as well as (ii) increases the number of dead seeds among non-germinated ones. We used fruit samples collected in Kraków, southern Poland, in 2013 and 2016, designating two different fruit storage periods of 3.5 years and 0.5 years, under dry, room temperature conditions. Seeds of all the observed species presented remarkably higher final percentage of germination after the short storage period than after the long one. The seeds subjected to the short fruit storage period achieved significantly higher values of Timson's index and coefficient of velocity, as well as significantly lower values of the mean germination time than samples subjected to the long fruit storage period. After the long storage period, a significantly higher number of dead seeds among non-germinated seeds was found in S. ×niederederi and S. virgaurea. The performed studies showing that the long fruit storage period led to low contribution of germinated seeds in S. ×niederederi and its parental species suggested that the longtime seed desiccation had a negative impact on final germination. Considering that the hybrid can be potentially cultivated for scientific, medicinal or ornamental purposes, the suggested fruit storage period, under dry, room temperature conditions, should be shorter than three years. However, we realize that the response to long storage may vary in different populations and, therefore, further investigations are needed. [ABSTRACT FROM AUTHOR]

The morphological differentiation and taxonomic treatment of lowland and high-mountain morphotypes within the Solidago virgaurea group are controversial. To clarify the taxonomic status of these taxa, we conducted a morphometric analysis of 1,746 individuals from 80 localities along an altitudinal gradient from the lowlands of northern Poland to the Carpathians and Sudetes of southern Poland. Multivariate morphometric analyses, cluster analyses and principal component analyses, were used to examine the morphological differentiation within the S. virgaurea group in Poland. Canonical discriminant analysis was applied to determine the morphological characters that best discriminate among the taxa. The stability of the high-mountain Solidago minuta morphotype was tested in an experimental field established in lowland Poland; individuals transplanted from various mountain sites were cultivated at this site, and the morphotypes remained stable in terms of their floral and vegetative characters. Multivariate analyses revealed two morphologically distinct taxa in the S. virgaurea group, which correspond to lowland S. virgaurea s. str. and high-mountain S. minuta as recognised in some European floras. The most important morphological characters for distinguishing the taxa are the number of tubular florets per capitulum, inner involucral bract width and involucre height. Vegetative and inflorescence characters appear to have less taxonomic value because they changed continuously with altitude. A key for identifying S. virgaurea and S. minuta in Poland is presented. [ABSTRACT FROM AUTHOR]