The aim of the study was to determine the relationship between the chemical composition of eight commercial essential oils (EsO) (garlic, grapefruit, lemon grass, tea tree, thyme, verbena, cajeput, and Litsea cubeba) and their fungistatic activity in relation to four species of Fusarium: F. avenaceum, F. culmorum, F. graminearum, and F. oxysporum. The species identification of Fusarium isolates was confirmed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometer. The determination of qualitative and quantitative chemical composition of the EsO was carried out using the gas chromatography–mass spectrometry (GC–MS) method. The fungistatic activity of EsO was assessed by using the method of poisoned substrates. The data were compiled in the STATISTICA 13.0 program. The chemical composition of the tested oils varied; the dominant fraction, except for grapefruit and garlic oils, were monoterpenoids. The greatest similarity to the action of the synthetic pesticide Funaben T was found in four oils, i.e., thyme, lemongrass, verbena, and Litsea cubeba. The studies showed that F. oxysporum and F. avenaceum were characterized by a higher resistance to low oil concentrations, and F. culmorum and F. graminearum by sensitivity. The fungicidal activity of two EsO-dominant monoterpenoids-thymol and citral—has been confirmed.

The history of coal mining in South Poland has left a legacy of many spoil heaps across the landscape. These have presented the opportunity to study their colonisation and spontaneous successional sequences over a long time period. We use the plant functional group (PFG) approach to characterize and compare species diversity on spoil heaps of different ages by utilising the ecological characteristics (PFG categories) of the species recorded during the course of spontaneous vegetation development. By changing species frequency into functional group frequency it was possible to find the significant differences in the functional composition of the studied vegetation and to analyze the dataset using non-parametric statistics. There was a small increase in the number of species over time, while the frequency of geophytes, nanophanerophytes and megaphanerophytes increased significantly. A significant increase was also recorded for the frequency of competitors, stress-tolerators and stress-tolerant competitors and for native species. We found that the significant differences in species composition measured as PFG diversity occurred between the youngest and the oldest age classes. The PFG approach provided valuable insights into the nature of the species composition of the developing vegetation on hard-coal mine spoil heaps. We suggest that it could be usefully applied in restoration practice in the future by facilitating the natural colonization of native species adapted to local conditions and thus retaining the local gene pool in these areas.

BackgroundThe development of cell pattern in the surface cell layer of the shoot apex can be investigated in vivo by use of a time-lapse confocal images, showing naked meristem in 3D in successive times. However, how this layer is originated from apical initials and develops as a result of growth and divisions of their descendants, remains unknown. This is an open area for computer modelling. A method to generate the surface cell layer is presented on the example of the 3D paraboloidal shoot apical dome. In the used model the layer originates from three apical initials that meet at the dome summit and develops through growth and cell divisions under the isotropic surface growth, defined by the growth tensor. The cells, which are described by polyhedrons, divide anticlinally with the smallest division plane that passes depending on the used mode through the cell center, or the point found randomly near this center. The formation of the surface cell pattern is described with the attention being paid to activity of the apical initials and fates of their descendants.ResultsThe computer generated surface layer that included about 350 cells required about 1200 divisions of the apical initials and their derivatives. The derivatives were arranged into three more or less equal clonal sectors composed of cellular clones at different age. Each apical initial renewed itself 7–8 times to produce the sector. In the shape and location and the cellular clones the following divisions of the initial were manifested. The application of the random factor resulted in more realistic cell pattern in comparison to the pure mode. The cell divisions were analyzed statistically on the top view. When all of the division walls were considered, their angular distribution was uniform, whereas in the distribution that was limited to apical initials only, some preferences related to their arrangement at the dome summit were observed.ConclusionsThe realistic surface cell pattern was obtained. The present method is a useful tool to generate surface cell layer, study activity of initial cells and their derivatives, and how cell expansion and division are coordinated during growth. We expect its further application to clarify the question of a number and permanence or impermanence of initial cells, and possible relationship between their shape and oriented divisions, both on the ground of the growth tensor approach.Electronic supplementary materialThe online version of this article (10.1186/s13007-017-0262-7) contains supplementary material, which is available to authorized users.

In contrast to seed plants, the roots of most ferns have a single apical cell which is the ultimate source of all cells in the root. The apical cell has a tetrahedral shape and divides asymmetrically. The root cap derives from the distal division face, while merophytes derived from three proximal division faces contribute to the root proper. The merophytes are produced sequentially forming three sectors along a helix around the root axis. During development, they divide and differentiate in a predictable pattern. Such growth causes cell pattern of the root apex to be remarkably regular and self-perpetuating. The nature of this regularity remains unknown. This paper shows the 2D simulation model for growth of the root apex with the apical cell in application to Azolla pinnata. The field of growth rates of the organ, prescribed by the model, is of a tensor type (symplastic growth) and cells divide taking principal growth directions into account. The simulations show how the cell pattern in a longitudinal section of the apex develops in time. The virtual root apex grows realistically and its cell pattern is similar to that observed in anatomical sections. The simulations indicate that the cell pattern regularity results from cell divisions which are oriented with respect to principal growth directions. Such divisions are essential for maintenance of peri-anticlinal arrangement of cell walls and coordinated growth of merophytes during the development. The highly specific division program that takes place in merophytes prior to differentiation seems to be regulated at the cellular level.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-013-1950-9) contains supplementary material, which is available to authorized users.

The morphological and cytogenetic features of the natural autotetraploid Arabidopsis thaliana ecotype Warschau (Wa-1) were investigated. Most of the Warschau plant organs that were analyzed showed higher size values in comparison with diploid Columbia plants. The tetraploid chromosome number was confirmed by analysis of mitotic metaphase cells and rDNA loci were localized. 35S rDNA loci were present on chromosomes 2 and 4, while 5S rDNA, which is polymorphic among A. thaliana ecotypes, were present on chromosomes 4 and 5. Well-characterized autotetraploid plant material was used for in vitro culture to investigate somaclonal variation. Efficient regeneration through organogenesis was achieved. Most of the plants obtained in vitro exhibited an unchanged ploidy level. Detailed cytogenetic analysis that included chromosome, chromocenters and rDNA signals numbers, revealed the stability of regenerants. Based on these data we recommend the ecotype Warschau as a well-characterized plant material for future investigations on the consequences of polyploidy for the genome.