There is an increasing need for the discovery of reliable and eco-friendly pesticides and natural plant-derived products may play a crucial role as source of new active compounds. In this research, a lipophilic extract of Onosma visianii roots extract containing 12% of shikonin derivatives demonstrated significant toxicity and inhibition of oviposition against Tetranychus urticae mites. Extensive chromatographic separation allowed the isolation of 11 naphthoquinone derivatives that were identified by spectral techniques and were tested against Tetranychus urticae. All the isolated compounds presented effects against the considered mite and isobutylshikonin (1) and isovalerylshikonin (2) were the most active, being valuable model compounds for the study of new anti-mite agents.

Background and Objectives: Polyploidisation and frequent hybridisation play an important role in speciation processes and evolutionary history and have a large impact on reproductive systems in the genus Crataegus. Reproductive modes in selected diploid and polyploid taxa in eastern Slovakia were investigated and analysed for the first time. Materials and Methods: Diploid, triploid, and tetraploid hawthorns were tested for self-pollination, self-compatibility, and self-fertilisation. Pollination experiments were performed within and between diploid and triploid species to determine the possibilities and directions of pollen transfer under natural conditions. Seeds from crossing experiments and open pollinations were analysed using the flow cytometric seed screen method. Results: These experiments demonstrated that sexual reproduction, cross-pollination, and self-incompatibility are typical of the diploid species Crataegus monogyna and C. kyrtostyla. Seeds produced by self-fertile tetraploid C. subsphaerica were derived from both meiotically reduced and unreduced megagametophytes. Conclusions: Experimental results concerning triploid C. subsphaerica and C. laevigata × C. subsphaerica are ambiguous but suggest that seeds are almost exclusively created through apomixis, although a few sexually generated seeds were observed. In the genus Crataegus, pseudogamy is a common feature of polyploid taxa, as in all cases pollination is essential for regular seed development. Research Highlights: We suggest that all studied Crataegus taxa produce reduced pollen irrespective of ploidy level. Moreover, we emphasise that triploids produce apparently aneuploid pollen grains as a result of irregular meiosis. They are also capable of utilising pollen from 2x, 3x, or 4x donors for pseudogamous formation of endosperm.

Somatic polyploidy or endopolyploidy is common in the plant kingdom; it ensures growth and allows adaptation to the environment. It is present in the majority of plant groups, including mosses. Endopolyploidy had only been previously studied in about 65 moss species, which represents less than 1% of known mosses. We analyzed 11 selected moss species to determine the spatial and temporal distribution of endopolyploidy using flow cytometry to identify patterns in ploidy levels among gametophytes and sporophytes. All of the studied mosses possessed cells with various ploidy levels in gametophytes, and four of six species investigated in sporophytic stage had endopolyploid sporophytes. The proportion of endopolyploid cells varied among organs, parts of gametophytes and sporophytes, and ontogenetic stages. Higher ploidy levels were seen in basal parts of gametophytes and sporophytes than in apical parts. Slight changes in ploidy levels were observed during ontogenesis in cultivated mosses; the youngest (apical) parts of thalli tend to have lower levels of endopolyploidy. Differences between parts of cauloid and phylloids of Plagiomnium ellipticum and Polytrichum formosum were also documented; proximal parts had higher levels of endopolyploidy than distal parts. Endopolyploidy is spatially and temporally differentiated in the gametophytes of endopolyploid mosses and follows a pattern similar to that seen in angiosperms.