Piotr Szkudlarz

Variability of stomata and 45S and 5S rDNAs loci characteristics in two species of Anthoxanthum genus: A. aristatum and A. odoratum (Poaceae)

Diploid Anthoxanthum odoratum and tetraploid A. aristatum were compared with respect to stomatal guard cell lengths, and stomatal density at adaxial and abaxial surfaces of the lamina. Further, the genome size of both species was determined by flow cytometry, and the number as well as the chromosomal distribution of 5S and 45S rDNAs were examined using FISH with ribosomal DNA (rDNA) probes. The average length of stomatal guard cells in A. odoratum was shown to be greater than that for A. aristatum, but the ranges overlapped. Moreover, reduction in stomatal frequency was found at higher ploidy levels.The genome size was 6.863 pg/2C DNA for A. aristatum and 13.252 pg/2C DNA for A. odoratum. A. aristatum has four sites of 5S rDNA in its root-tip meristematic cells, whereas A. odoratum has six. Both species have six sites of 45S rDNA. Chromosomal localization of the rDNA varied, which suggests that chromosome rearrangements took place during Anthoxanthum genome evolution.

Morphological characters of the seed coat in selected species of the genus Hypericum L. and their taxonomic value

Abstract Eight Hypericum species are native to Poland: H. elegans Stephan ex Willd., H. hirsutum L., H. humifusum L., H. maculatum Crantz, H. montanum L., H. perforatum L., H. pulchrum L., and H. tetrapterum Fr. Only seeds of H. elegans were investigated in detail in Poland before, so here we present results of qualitative and quantitative analyses of seed morphology of the other 7 species, based on characters like seed length, width, and shape, seed coat sculpture, shape of epidermal cells of the testa, and number of epidermal cells along the seed axis. The results show that seeds of the studied species are small, 0.56-1.15 mm long and 0.26-0.49 mm wide. In SEM images, seed coat sculpture is reticulate in 5 species, papillate in H. hirsutum, and cup-shaped in H. pulchrum. The differences are caused by the varied final development of the testa epidermis, which constitutes the outer layer of the seed coat. The mean number of epidermal cells along the seed axis ranges from 22 to 33. Results of cluster analysis, based on the agglomeration method and including also published data on seeds of H. elegans, show that the variation in the investigated characters of seeds is reflected in the taxonomic division of the genus into sections.

Morphological variability of the two altitude vicariants, Anthoxanthum odoratum L. s.s. and Anthoxanthum alpinum in the Babia Góra Massif (Western Carpathian Mountains – Żywiec Beskid, Poland)

Abstract Anthoxanthum odoratum, a species occurring below the upper forest limit on the Babia Góra Mountain, is replaced by Anthoxanthum alpinum in the subalpine and alpine belts. It is a typical example of altitudinal vicariance. The aim of the study was to determine the range of morphological variability within the populations of A. odoratum and A. alpinum along an altitudinal transect. Special attention was paid to specimens growing in the transition zone between both species. Plant material was collected from 11 localities and samples were examined with respect to 24 morphological traits of the panicle. Results were analysed with the use of multidimensional statistical methods. It was found that A. alpinum grows above the upper forest limit. Populations of this species have a relatively small range of variability of the studied traits. Samples originating from the contact zone, situated at the altitude of c. 1166 m above sea level, consist of individuals representing both species. In turn, samples collected below the upper forest limit represent A. odoratum and occasionally A. alpinum, and reveal considerable morphological differentiation.