Search

Triassic limestone areas of Thuringia are well-known for their richness of hybrids between S. aria and S. torminalis (subgenus Tormaria). Those have been originally described as endemic taxa (i.e. Sorbus heilingensis, S. isenacensis). However, the former endemics have been recently synonymized with S. × decipiens (Karpatiosorbus × hybrida (Bechst.) Sennikov & Kurtto) due to diploidy and putative sexuality. Generally, crosses between diploid and sexual parents should segregate and intermediates as well as morphotypes close to the parents should be the outcome. To test for clonality versus segregation, we investigated progeny of 10 Tormaria mother trees, derived from open pollination. Three to ten seedlings of each mother tree were cultivated, and six leaf characters were measured being indicative for subgenus Aria, Tormaria and Torminalis. For genetic characterization, we used three ISSR microsatellite markers and one chloroplast marker. The progeny of nine mother trees segregated; the S. aria genome prevailed in pollen clouds. One polyploid mother tree, however, produced partly clonal progeny and proved to be polyploid and facultative apomictic. This means that in Thuringian Tormaria polyploidization occurs at low rates starting from diploid hybrids. Exact comparisons between geno- and phenotypes of the progeny proved a frequent uncoupling between genetic markers and genes responsible for leaf morphology, pointing to excessive genomic rearrangement within Tormaria mother trees. Only 1/3 of Tormaria-genotypes possessed the Tormaria-phenotype. Most of them belong to S. aria and to S. aria forma incisa, a S. aria type with slightly incise leaves. This means that plasticity of parental species may be explained by excessive introgression between S. aria and S. torminalis. [ABSTRACT FROM AUTHOR]

Ongoing climate change increasingly affects growth conditions of native conifers such as Picea abies (Norway spruce) and Pinus sylvestris (Scots pine) in Central Europe. These conifers are primarily cultivated for wood production. To obtain ecologically and economically stable forests, forestry seeks alternative species that might be less prone to novel climatic conditions, such as Cedrus libani (Lebanon cedar). We aim at investigating growth responses to climatic factors of C. libani compared to native P. abies and P. sylvestris in Central Europe for 25 years (1994–2019). Growth responses were used as a proxy for tolerance towards climatic stress events, such as heat and drought. Height, diameter at breast height (DBH) and radial increment were measured for 40-year-old tree stands of C. libani and native conifers. Radial growth responses to selected climate parameters were analysed using bootstrapped correlations with detrended growth index chronologies and growth response indices for drought years (2003, 2012, 2015, 2018). For C. libani, radial growth was positively correlated with high water availability in late winter and spring, while for P. abies, February and summer and for P. sylvestris, July showed such a relationship. Cedrus libani exhibited the highest resistance, recovery, and resilience in response to climatic extremes. Against the background of climate change, C. libani could serve as an alternative conifer species to establish climate-resistant viable forests in Central Europe. [ABSTRACT FROM AUTHOR]

Temperate grasslands exhibit strong spatial and temporal variation in water regimes. Thus, grassland plants experience potentially stressful water regimes, which may influence their tissue silicon (Si) and nitrogen (N) concentrations. Plant Si and N concentrations play important ecological roles in temperate grasslands, for example, by influencing plant performance and herbivory, yet comparisons of species' responses to a broad range of water regimes, including drought, waterlogging and flooding, are lacking.We conducted a mesocosm experiment with 10 temperate grassland species of two life‐forms (grasses and forbs) exposed to four different soil water regimes (drought, a benign control, waterlogged and flooded conditions), and analysed their Si and N concentrations.Grasses showed lower Si concentrations under drought and flooding compared to the benign control and the highest concentrations emerged under waterlogging. Overall, plant Si responses of grasses were more uniform, while in forbs, responses varied both in direction and magnitude across species. For N concentrations, all species and life‐forms showed the highest concentrations under drought compared to the benign control, while half of the species exhibited decreasing concentrations under waterlogging and/or flooding. The water regimes, especially waterlogging and flooding, induced changes in species rankings of plant Si and N concentrations, with stronger shifts in forbs than in grasses.Our results indicate that spatial and temporal variation of water regimes may influence plant Si and N concentrations in temperate grassland species. Plant Si responses to water regimes might be highly species‐specific in forbs but more similar in grasses, whereas plant N responses are likely to be relatively uniform across species and life‐forms.The strong plasticity in plant Si and N concentrations we observed might have pervasive consequences for ecological processes, such as herbivory. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]