Abstract:The study was conducted on six sites that are dominated by Japanese knotweed (Reynoutria japonica) and that vary in the level of industrialization and habitat transformation by humans. The aim of the research was to investigate the chemical-physical features of soil under a closed and dense canopy of R. japonica, the chemical composition of the R. japonica leaves, and to compare the content of certain elements in the soil-plant-soil system. The soil organic carbon (C org ) content varied from 1.38±0.004% to 8.2±0.047% and the maximum in leaves was 49.11±0.090%. The lowest levels of total nitrogen (N tot ) in soil were recorded on the heavily disturbed sites (till 0.227±0.021%). Soil pH varied greatly, ranging from acidic (pH=4.0) to neutral (pH=7.7). Heavy metal content differed significantly among the study sites. At all of the sites, both in the case of soil and plant leaves, Zn was a dominant element and its concentration ranged from 41.5 to 501.2 mg·kg -1 in soils and from 38.6 to 541.7 mg·kg -1 in leaves. ) were observed on the site that had been influenced by agricultural practices. The results obtained showed that R. japonica is able to accumulate high levels of heavy metals.

Coal-waste dumps superimposed on former rubbish dump frequently undergo selfheating and selfignition of organic matter dispersed in the waste. The special conditions for plant growth generated as a result have been investigated since 2008 on the municipal dump reclaimed with coal wastes in Katowice-Wełnowiec, Poland. The plants observed most frequently where heating has occurred are Sisymbrium loeselii, Artemisia vulgaris, Sonchus arvensis, Chenopodium album, Achillea millefolium, Cirsium arvense, Amaranthus retroflexus, Atriplex nitens and Solanum nigrum. Some new, rare species such as Portulaca oleracea, first noticed in 2011, may be added. Most of encroaching species are annual, alien archeophytes and neophytes. Native species are mainly perennials. The majority of these species show a tendency to form specimens of huge size (gigantism). The abundance of emitted CO2 and nitrogen compounds is the likely cause of this. Additionally, the plants growing there are not attacked by insects. The heating of the ground liquidates the natural seed bank. After cooling, these places are seeded by species providing seeds at that very moment (pioneer species). Heated places on the dumps allow plant growth even in the middle of winter. As the seasonal vegetation cycle is disturbed, plants may be found seeding, blooming and fruiting at the same time.

The root-feeding aphids of the tribe Tramini have been cited as a possible case of ancient apomixis, as there are no substantiated records in the literature of a functional bisexual generation, even in common and well-known European species. The karyotypic variation found in this group, involving considerable structural heterozygosity within species, also pointed to the decay of diploidy that would be an expected consequence of loss of sexuality and absence of meiosis. However, we have now found a small number of oviparae (mating females) and males in populations of the common species Trama troglodytes. Fertilized eggs were not obtained, but adult oviparae contained large, yolky eggs. The single adult male was apterous, small and blind, but had fully developed mouthparts and genitalia, and contained mature sperm. Both sexual morphs are described, and the karyotrypic variation is reassessed in the light of these ® ndings. Occasional sexual reproduction is in concordance with recent molecular evidence that some recombination occurs in T. troglodytes and related species.

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The paper provides data on a new antropophyte species - Typha laxmannii Lepech. which spreads throughout Poland as a hemiagriophyte. Its present distribution in Poland is given on a cartogramme map in a 10×10 km square grid and its geographic element, population numbers and notes on habitats are provided. An identification key to 5 species of the Typha genus, two native, one new which is the topic of this paper, and two which can be expected to be discovered in Poland