Chemical composition of the plants of loess steppes in Hungary

The first two stages of the successional series on loess (Agropyro-Kocliietum, Salvio-Festucetum rupicolae) differ from each other in their Holistic composition, the total element content of their soils and plant species as well as their water demand. Chrysopogon gryllus, a characteristic species of the loess steppe, belongs to the calciotroph physiotype according to the Ca/K ratio in its leaves. The leaves of this species contain relatively high concentrations of Ca and Mg and a low concentration of N. The high C/N ratio in the leaves and roots of Chrysopogon gryllus should indicate that the mineralization dynamics is slowed down in the stands dominated by this species. Barbula cordata, a moss species of the Salvio-Festucetum rupicolae community, accumulates very high amounts of heavy metals from its surroundings. In the Agropyro-Kochietum community, Bromus species accumulated the highest amounts of heavy metals in their leaves

Chemical composition of the plants of loess steppes in Hungary

The first two stages of the successional series on loess (Agropyro-Kocliietum, Salvio-Festucetum rupicolae) differ from each other in their Holistic composition, the total element content of their soils and plant species as well as their water demand. Chrysopogon gryllus, a characteristic species of the loess steppe, belongs to the calciotroph physiotype according to the Ca/K ratio in its leaves. The leaves of this species contain relatively high concentrations of Ca and Mg and a low concentration of N. The high C/N ratio in the leaves and roots of Chrysopogon gryllus should indicate that the mineralization dynamics is slowed down in the stands dominated by this species. Barbula cordata, a moss species of the Salvio-Festucetum rupicolae community, accumulates very high amounts of heavy metals from its surroundings. In the Agropyro-Kochietum community, Bromus species accumulated the highest amounts of heavy metals in their leaves

Nitzschia austriaca Hustedt: a characteristic diatom of Hungarian inland saline waters including a morphological comparison with the type material

A detailed scanning electron microscopic investigation was carried out to clarify the taxonomic status of a small sigmoid Nitzschia species, a potential indicator of Central European soda waters. We found this taxon to be one of the dominant epiphytic diatoms collected from sodic bomb crater ponds at Apaj (Hungary). The large population allowed for a morphometric comparison based on frustule ultrastructure with the type material of the most similar species, Nitzschia austriaca Hustedt that was originally described from a soda pan in the region. The results clearly demonstrated an overlap between the Apaj population and the type material of N. austriaca (based on NMDS analysis), therefore we argue that they represent the same taxon. An emended diagnosis of N. austriaca is given. Total suspended solids and total phosphorous proved to be the most important factors predicting the occurrence of the species, with possible interactive effects of conductivity and pH. We then expanded the distribution of the species by revisiting data originating from previous large-scale surveys targeting sodic habitats in Hungary. On the basis of our results, N. austriaca is a characteristic species for Central European soda waters, including the protected astatic soda pans, indicating their typical chemical and physical characteristics.</jats:p

A new statistical method for the comparison of biplots with the same objects and variables

Ordinations are compared most commonly by Procrustes methods applicable to points belonging to the same domain, either the objects or the variables describing them. However, no published approach applies to biplots which visualize principal component ordinations of objects and variables simultaneously.To fill this gap, this paper provides a new procedure based on two fundamental, scale-invariant properties of biplots: the cosine of the angle between the vectors pointing to every pair of objects and variables and the mean of the relative length of the two vectors. The method applies to situations in which the number of objects is the same in all ordinations, the number of variables is also the same and, additionally, there is one-to-one correspondence between the points in the different ordinations. The new method is illustrated with two artificial examples and is also applied to the comparison of biplots obtained from real field data representing samples repeated in the same locations over time.It is demonstrated that the new method reveals the similarities and differences between alternative biplots obtained for a given set of objects and variables.We expect that, thanks to the widespread use of principal component analysis in science, the method will receive applications in any studies in which interest lies in the comparison of simultaneous ordinations of objects and variables