The experimental design of the present study allowed us to compare the sensitivity of various methods and parameters for detecting plant responses to heavy metal-induced oxidative stress. The level of glutathione and the enzyme activities of guaiacol peroxidase and glutathione reductase could be used as a rapidly determined early warning system in toxicity studies.

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Luzula sect. Luzula is one of the taxonomically most intricate groups of angiosperms, where diversification is mostly driven by true polyploidy and agmatoploidy (fission of chromosomes) leading to three different karyotypes (whole chromosomes -AL, halfsized chromosomes -BL and quarter-sized chromosomes -CL). Morphologically, the taxa are often difficult to distinguish, and genome size data coupled with karyological investigations are currently the most reliable means for their identification. For the Balkan Peninsula, one of the botanically least studied areas of Europe, ten taxa from this section have been reported, but little is known about their distribution. We here estimated the nuclear DNA amount (genome size, GS) using interphase-peak DNA image cytometry and counted the chromosomes for 33 populations of five species of Luzula sect. Luzula mostly from mountainous areas of the Balkan Peninsula and the adjacent southeastern Alps. Five taxa have been confirmed, of which L. divulgatiformis is new for Croatia and L. exspectata for Macedonia and Serbia. The most common species in the Dinaric mountains appears to be diploid (2n = 12 AL) L. taurica, for which the GS (2C = 0.83 pg DNA, fitting well in the range of previously determined values of diploid taxa) has been determined for the first time. The GS and karyotypes of other taxa (L. campestris, L. divulgatiformis, L. exspectata, L. multiflora subsp. multiflora) correspond well to previously published values. An identification key for the Balkan taxa of Luzula sect. Luzula is also included.

-Plant essential oils are potential food preservatives due to their inhibitory effects on bacterial and fungal growth. Antifungal activities of common thyme (Thymus vulgaris) essential oil were tested against endophytic fungi grown from wheat (Triticum aestivum) grain, molecularly identifi ed as Alternaria alternata, Alternaria infectoria, Aspergillus fl avus, Epicoccum nigrum and Fusarium poae. Their susceptibility to thyme essential oil was tested in vitro, and ranged from fungicidal to fungistatic. Treatment combinations of prior grain surface sterilization with hypochlorite and direct/indirect treatment with the essential oil were used, which showed strong effects on infection incidence and germination. Direct soaking of the wheat grain in the essential oil was particularly effective, but inhibited both fungal growth and seed germination. In contrast, indirect treatment of the grain with the essential oil (i.e., fumigation) inhibited fungal growth without negative effects on seed germination. In combination with grain surface sterilization with hypochlorite, indirect treatment with thyme essential oil reduced these fungal infections even more. Since thyme essential oil is safe for plants and consumers, in the form of fumigation it could be used as a protectant of storage containers for wheat grain intended for sowing and for food production.

Polyploidisation-and, additionally, agmatoploidy (concerted fission of chromosomes) in some plant groups-have significantly contributed to the diversification of alpine plant species. Both processes have driven the diversification of Luzula sect. Luzula, leading to a number of different karyotypes, rendering it one of the most intricate plant groups in the Alps. For the Eastern Alps eight species with six karyotypes were reported, but their distribution is insufficiently known. A herbarium revision of 1044 specimens revealed that L. alpina, L. campestris, L. exspectata, L. multiflora and L. sudetica are widespread across the Eastern Alps; L. exspectata is thus new for the Northern Alps and new for Germany, France and possibly Croatia. Luzula divulgata is distributed in the easternmost Alps and adjacent areas, with only a few indications for the western Eastern Alps. Luzula divulgatiformis is new for the Alps where it was recorded in the Southern Alps and southerly adjacent areas. Luzula campestris, L. divulgata and L. divulgatiformis are distributed from lowlands to the montane belt, L. alpina, L. exspectata and L. sudetica are high-elevation species and L. multiflora occurs from lowlands to the alpine belt. Additionally, we estimated genome size (GS) and karyotypes for 20 populations and revealed four karyotypes corresponding to three ploidy levels. The GS of diploid L. exspectata and L. sudetica was 0.83 pg DNA, tetraploid L. alpina had a double (1.63 pg) and hexaploid L. multiflora a triple (2.48 pg) GS. Our study underlines the importance of large-scale herbarium revisions of intricate taxa, combined with cytological methods, even in well-studied mountain areas such as the Alps and poses new hypotheses regarding the evolution of this polyploid-agmatoploid group.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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