Blue honeysuckle (Lonicera caerulea L.) is a promising berry crop producing edible early-ripening berries with a valuable chemical composition. We evaluated the genetic diversity of native L. caerulea populations from the western (Baltic states) and eastern (the Russian Far East and Japan) edges of the Eurasian range using inter-simple sequence repeat (ISSR) and chloroplast DNA (psbA-trnH and trnL-trnF) markers. The genetic relationships of populations and genotypes were analyzed using principal coordinate and cluster analyses (neighbor joining and Bayesian clustering). Sampling was carried out in two disjunct areas of this circumpolar species and the analyses showed clustering of individuals and populations according to geographic origin. The analysis of genetic structure based on ISSR markers showed that the studied populations of L. caerulea were highly differentiated. However, sequence analysis of two chloroplast DNA (cpDNA) regions revealed no phylogeographic structure among the populations. We also found that the eastern populations of blue honeysuckle had significantly greater genetic diversity parameters than the populations from the Baltic region. This finding correlates with the endangered status of blue honeysuckle in the Baltic states.

We studied genetic diversity within and among populations of warty cabbage (Bunias orientalis L.), which is an alien species in Lithuania and other Baltic countries. In Lithuania, this weed colonises two main types of habitats: railway/roadsides and meadows on riversides. The aim of this study was to assess the genetic structure of invasive populations of B. orientalis in Lithuania and consider the impact of diverse habitats on the partitioning of genetic diversity using inter-simple sequence repeat (ISSR) markers. An analysis of molecular variance (AMOVA) carried out on the basis of ISSR showed that there is high genetic differentiation (46%) among populations of B. orientalis, which is probably caused by the founder effect and limited gene flow. However, we observed no impact of habitat on the genetic difference among populations. Similar levels of ISSR polymorphic loci were observed in riverside (P = 31.67%) and railway/roadsides (P = 30.51%) populations. UPGMA cluster analysis and principal coordinate analysis (PCoA) also did not show grouping of studied populations according to habitat type. High genetic differentiation among populations, as indicated by ISSR markers, confirm multiple independent introductions of this species in Lithuania.

Common reed is often used as a model plant to study the anthropogenic impacts on ecosystems at local and global scales. As a community-forming species, it is directly exposed to the impacts of human activities on the ecosystem. The aim of our study was to evaluate the patterns of genetic diversity in common reed stands located in habitats that are differently affected by anthropogenic factors. We studied whether riverbed modifications, land cover in the neighborhood of the stand and the chemical and physical parameters of the river water affect the genetic diversity of P. australis at the studied sites. Using DNA fingerprinting, we genotyped 747 plants from 42 sites located in 16 small Lithuanian rivers. Bayesian clustering and principal coordinate analysis revealed two main gene pools at the population (river) level. At the site level (i.e., considering all sites independently of their rivers), polymorphism was high even between sites in the same river. Our study revealed a negative relationship between the concentration of nitrogen compounds and the genotypic richness of P. australis populations. We did not find any correlations between the other chemical parameters of the water and the parameters of the genetic diversity. Additionally, there were no genetic differences between sites in modified and unmodified river sections or between sites that differed in land cover type in the neighborhood of the stand.

Understanding the growth dynamics of spore-bearing clonal plant sporophytes and the influence of abiotic and biotic factors is crucial for predicting the persistence of club moss populations and implementing effective habitat management techniques. Despite this, the longevity and development of club-moss populations are rarely studied. This study adopted an integrated approach to assess the probability of repetitive young sporophyte recruitment via sexual propagation in Lycopodium annotinum L. and Lycopodium clavatum L. The size–age problem of clonal spore-bearing forest plants and their niche segregation were addressed. The canopy characteristics, insolation, small-scale disturbance, and genetic polymorphism were studied in temperate semi-natural Scots pine forests in Lithuania. Based on the size of the clones discovered, we hypothesize that initial sporophyte emergence occurred in 20-year-old pine stands, with subsequent sporophyte emergence continuing over time. The emergence was related to small-scale disturbances. High genetic polymorphism indicates that all sporophyte stands studied likely emerged via sexual reproduction. According to Ellenberg values, L. annotinum is related to shady habitats, but our findings show both species coexisting abundantly in the more open habitat, supposedly more suitable for L. clavatum.No significant differences in vegetation relevés and light availability was detected using hemispheric images.

The red raspberry (Rubus idaeus L.) is widely distributed in Lithuania and occupies a range of habitats. The presence of coadapted gene pools in local populations of R. idaeus is a question of interest not only to plant scientists, but also to plant breeders. In this study, we investigated the genetic structure of R. idaeus and the influence of local habitats on the genetic diversity within and among populations. Nineteen populations of R. idaeus were sampled from different habitats in various agroclimatic subregions of Lithuania, and analyzed using RAPD markers. 113 RAPD bands were identified among 315 individuals; 84.31% of these were polymorphic. The mean values of Shannon’s information index for different populations ranged from 0.341 to 0.455. Nei’s gene diversity established within populations averaged 0.266. An AMOVA revealed 74% of genetic variation among individuals within populations of R. idaeus, and 23% among populations. The remaining genetic variation was distributed among populations from different agroclimatic subregions (3%). The results of this study suggest that the genetic structure of R. idaeus populations in Lithuania may be influenced partially by isolation by distance as well as by local environmental conditions.

Sago pondweed (Stuckenia pectinata (L.) Börner) is a genetically and ecologically diverse submerged macrophyte, notable for its versatile reproductive characteristics, with a broad global distribution, excluding only the Arctic and Antarctic regions. This cosmopolitan species remains underexplored genetically in Lithuania compared to some other European regions. The aim of this study was to investigate the state and distribution of genetic diversity across Lithuanian river populations. We analyzed genetic variation in ten riverine populations using both simple sequence repeats (SSRs) and intersimple sequence repeats (ISSR). Genetic distances between genotypes and populations, as revealed by SSR markers, correlated with those determined using ISSR markers, confirming consistency across the two marker systems. STRUCTURE analysis revealed the presence of two distinct genotype pools. Our study demonstrated that the majority of genetic variation resides within populations, with an F_ST value of 0.212 (SSR) and a Φ_PT value of 0.352 (ISSR). These findings suggest high genetic differentiation among populations. The absence of a relationship between genetic diversity and hydrochemical or hydromorphological parameters at plant collection sites suggests that the population structure of this species is shaped primarily by evolutionary and/or demographic mechanisms, rather than by local environmental hydrochemical conditions. Overall, this study revealed high within-population genetic diversity and underlying genetic structure in S. pectinata populations across Lithuanian rivers.