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Extensive parts of subtropical South America are covered by grassland vegetation, despite climatic conditions that allow for forest development, and fire may have been an important factor in the evolutionary history of these grasslands. In a regularly burned grassland area, situated in a forest–grassland-mosaic near Porto Alegre, RS, Brazil, life form spectrum and plant species’ reaction to fire were...
Nectar composition and concentration were analyzed for 75 samples of 70 species of Acanthaceae representing all major intrafamiliar groups. Analyses of variance were conducted to test for significant differences between pollination syndromes and between taxonomical or phylogenetic groups (∼genera). The available data indicate that the characteristics of nectar in Acanthaceae are predominantly determined...
Since the Roman time, the walnut tree (Juglans regia L.) has been cultivated in gardens and orchards in large parts of Europe, but only since Karl The Great (742–814) the walnut tree has been introduced to Tyrol (Austria) and other Alpine regions in Central Europe. As late as the beginning of the 20th century no wild populations but only cultivated trees are reported for inner Alpine valleys of Tyrol...
We investigated the geographical distribution of genetic variation in 67 individuals of Triglochin maritima from 38 localities across Europe using AFLP markers. Analysis of genetic variation resulted in the recognition of two major genetic groups. Apart from few geographical outliers, these are distributed (1) along the Atlantic coasts of Portugal, Spain and France and (2) in the North Sea area, the...
The superpáramo is an island-like ecosystem located on the highest mountain-tops in the equatorial Andes and its flora is composed of genera that are distributed in both tropical and temperate areas. We were interested in studying: (1) whether the proportions of tropical and temperate genera change along the altitudinal gradient of the superpáramo and (2) whether the proportions of tropical and temperate...
This study examines the seedling emergence and fruiting success of plant species endozoochorously dispersed by sheep in a field experiment in a Koelerion glaucae area. We designed a factorial experiment (faeces/soil disturbance/successional stage/year) that mimics sheep-mediated microsites and analysed all occurring vascular plant species from September 2002–December 2004. The faeces samples were...
A large variety of reproductive patterns is present among alpine plants to ensure the persistence of populations in such harsh environments. In the present study, the role of spontaneous selfing and its contribution to the actual reproductive success of an alpine pioneer plant was investigated. The results showed that Saxifraga aizoides is clearly self-compatible. Open-pollinated flowers exhibited...
Seed micromorphology in 22 species, capsule surface in 28 species and capsule hairs in 20 species of genus Verbascum distributed in Iran were studied using scanning electron microscopy. The seed surface is ridged or alveolate among the studied species. Depth and density of the alveoli or ridges, size of polygonal cells along with arrangement of vesicles on the walls separating the polygonal cells...
Asarum europaeum subsp. europaeum (Aristolochiaceae) is a rhizomatous herb forming distinct patches in calcareous broadleaved forests. Within natural stands, patches were mapped. In two regions, at least four patches were dug out, and connections between leaf modules through rhizomatous spacers were checked for signs of clonal reproduction (decay, breaking). Modules were sampled for amplified fragment...
In clonal plants, a clonal fragment is a basic unit. There may exist clonal integration that is often regarded adaptive. By definition, a larger clonal fragment comprises more interconnected ramets and/or occupies a larger area of the habitat. When the habitat is so heterogeneous in terms of essential resources that the resources the whole clonal fragment needs can be captured only in a limited number...
The intra- and inter-population variation of Juniperus oxycedrus subsp. oxycedrus were examined biometrically on the basis of morphological characters of needles, seeds and cones. Cluster analysis of Euclidean distances and discriminant analysis were performed to verify the hypothesis of geographic differentiation and origin from the West- and East-Mediterranean Pleistocene refugial regions. The West-Mediterranean...
The relationship between individual heretozygosity and fitness was explored in the perennial larkspur Delphinium bolosii (Ranunculaceae), an endangered species endemic to Catalonia (North-Eastern Spain), as a part of several studies prior to designing a programme for the reintroduction of this species in a locality where it has been extinct for approximately one century. Allozyme electrophoresis was...
In tropical montane forests, the wetness of leaf surfaces is an important parameter which may influence gas exchange, growth and vitality of leaves, and forest productivity. Thirty surface wetness sensors were operated during May–August 2004 in a vertical profile inside an old-growth lower montane rain forest of Central Sulawesi, Indonesia, with the objective to analyse spatial and temporal patterns...
In the Rothaargebirge (Northrhine-Westphalia) the interrupted club moss (Lycopodium annotinum L.) often grows in large (maximum size of patches observed: 18,000m 2 ) and dense (club moss cover 60–90%) clusters. By DNA amplification fingerprinting (DAF) analysis it was shown in three populations comprising a total of 69 samples that the clusters are of great genetical uniformity. Based on data...
This paper is about pollen ecophysiology, anther opening, pollen dispersal and the timing of the male and female phases in Parietaria judaica (Urticaceae).Ecophysiological (effects of different relative humidities (RHs) and osmotic relationships) and cytological methods (stigmatic receptivity, pollen viability, histology and histochemistry) were used to determine pollen and pollination features during...
Anther development, microsporogenesis and microgametogenesis in several species of Heliconia were investigated as part of a complementary embryological study of the Heliconiaceae. All studied Heliconia species present bithecate and tetrasporangiate anthers with fertile pollen grains; only H. rivularis, a natural hybrid, presented sterile pollen grains of variable size and no content. The anther wall...
The present study examines the seasonal and diurnal patterns of water management by plant species inhabiting the wall fissures of the ancient castle of Patras. Their water status (water potential), stomatal behaviour (leaf resistance and transpiration rate) as well as tissue water relations (turgor loss point, osmoregulation capability and cell wall elasticity) were recorded in relation to season,...
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