The grass species Cleistogenes serotina (L.) Keng, generally found in the mountainous region in Hungary, has been observed in the lowlands of the Great Hungarian Plain in the last few decades. Since its first recent mention in sand habitat as well it, has been found in several locations in the interfluve between the Danube and the Tisza. In cer...tain, sandy grasslands, the invasion of this species is considerable (e.g. near Fülöpháza the area invaded by Cleistogenes increased almost fourfold within six years). The success of invasion on new habitats is related to changes in the
characteristics of plants comparatively studied on mountain and sand populations.
We studied blades of leaves on different levels (1st, 5th and 10th) and from different biotops. Cuttings were made, with a thickness of 10-12 μm, at the middle of the blades. The cross sections were observed using a light microscope. Digitised images (DigitPlan) and survey data were arranged into a database.
The leaf structure is characterised by the kranz anatomy, and a double layered bundle sheath, which is typical of the aspartate type of C4 grasses. There were significant differences only in cross section area and the number of bundles for various ages of the leaves. There were more bundles in the older leaves than in the younger ones. We did not find any difference in the ratio of tissues among leaves of different ages and sources. According to our study, the ratio of leaf tissues characteristic to species was neither significantly influenced by the biotop, nor by the age of the leaves. However, there is a difference in tissues size. Summarising the results, the species can be considered „only” as ecotypes on the
different studied areas.
Our new result is that kranz anatomy can also be found in the leaf-sheath.
This research was supported by the Hungarian Scientific Fund (OTKA), grant No. T016511 and T026346.
The sward composition of different grasslands on Puszta Hortobágy has been developed according to prevailing abiotic and biotic factors. The abiotic conditions have been more or less constans for long periods of time, and the abiotic factors are determined by ecological conditions (climate, soil, topography). Among biotic factors grazing of he...rbivores was important in the development of Hortobágy grasslands for centuries (Sipos and Varga, 1993). Result of three-year investigations on the sward composition of grasslands utilised in different ways are presented. Data on ground cover, number of plant species, representation of different plant groups (grasses, sedge and bent-grass, herbs, legumes) and weeds are reported from six different grazed grassland types from Puszta Hortobágy.
In 1999-2001 a sward composition survey was conducted. Sample areas of 2x2 m2 were marked out in three replicates: on temporarily waterlogged grassland grazed by cattle (A), on dry grassland grazed by cattle (B), on dry grassland grazed by sheep (C), on dry grassland grazed by buffaloes (D), on dry grassland grazed by buffaloes and geese (E), on dry grassland cut for hay in May then grazed by geese (F). On the sample areas sward composition of grasslands was estimated according to Balázs (1949).
The average ground cover of different grasslands ranged between 60 and 100% (Table 2). The lowest value was found for grasslands C and E, which are grazed by sheep (C) and buffaloes and geese alternately (E). In these grasslands were some open spaces, on the other grasslands completely closed swards covers were observed.
The species diversity of these natural grasslands are high (Table 2). The grassland F, which were cut for hay in May had the lowest diversity (17-21). The highest number of species was found on grassland A and B (32-51), on other grazed grasslands (C, D, E) had 29-48 species.
The different plant groups had different representation in the total ground cover (Table 3). The number of herbs was always higher then that of grasses, but the cover of herbs was lower then that of grasses. The legumes and the sedge and bent grasses were present in high abundance in grassland A, but in the other grasslands were not.
The composition of herbs should be a warning for future utilisation systems on some grasslands of Hortobágy. Some species of herbs, e.g. Achillea millefolium, Artemisia vulgaris, Carduus acanthoides, Cirsium arvense, Cirsium vulgare Eryngium campestre, Galium mollugo, Galium verum, Ononis spinosa, Rumex crispus, Verbascum phlomoideus, Phragmites australis can be invasive on short grasslands.
biological methods, one among them is AFLP that is well applicable for taxonomic research. Bluegrass species, that are important components of meadow associations, thus their thorough knowledge is necessary in maintaining biodiversity, were examined with bringing this method to perfection.
Taxonomic relationship of the members of Poa pratens
We made a botanical survey of a seminatural meadow situated in the vicinity of Hajdúnánás-Tedej in Hungary, using traditional phytocenological methods. The habitat, based on its soil-, and botanical characteristics, can be classified into the category of saline meadows. One of the landscape ecological values of this area is its mosaic-like s...tructure and, as a consequence, this habitat can be divided into six characteristic associations with blurry borderlines and characteristic overlaps. Because of its rare plant species and species richness this area can be considered to be a valuable „seed bank” and a „stepping stone” in the ecological network among the larger, intensively cultivated fields. The area can be evaluated as moderately recovered, the natural species are dominant, but there are few disturbance tolerant species. Except for the two saline associations, the high grass associations, which make up about two-thirds of the habitat, are cut once a year; therefore, the agricultural utilisation of the area and its prevention against weediness are being assured at the same time.