The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In climate chamber and outdoor experiments we analysed germination traits of 42 vascular plant species typical of flood-meadows of the alliance Cnidion. In Central Europe such flood-meadows and their highly endangered character species are confined to large lowland river corridors with a dry and warm climate. Due to the prevailing ecological conditions, particularly the extremely high variability...
Melica macra Nees is a widespread grass of Central and Northern Argentina. It is considered an invasive weed in natural grasslands. The aim of the present paper is to describe the branching system of M. macra on the base of both the analysis of living plants obtained from seeds and maintained under cultivation, and the observation of plants growing in their natural habitat. The plants are cespitose...
Leaf morphology and anatomy, water relations, leaf life-span, and gas exchange of Erica arborea L., Erica multiflora L. and Rosmarinus officinalis L. co-occurring in the Mediterranean maquis developing along the coast near Rome were analysed in the period from May 2000 through December 2001. The year 2001 was characterised by a severe drought period from the beginning of June to the middle of September...
The inflorescences of the genus Nassauvia are analyzed following Troll’s comparative-morphological approach. Eight types of synflorescences are recognized, each defined by a particular combination of six developmental processes: truncation, proliferation, shortening of internodes, homogenization of paraclades, suppression of paraclades and shortening of peduncles. Decomposing each inflorescence type...
The effect of competition and artificially created soil heterogeneity was studied in a pot experiment. A tussock grass, Holcus lanatus, and the rhizomatous sedge Carex hartmanii were grown alone and in combination with another tussock grass, Molinia caerulea, in homogeneous and heterogeneous soil treatments. The heterogeneous treatment consisted of four compartments, two nutrient rich and two nutrient...
We tested whether alpine plants increase their effort to attract pollinators to compensate for assumed pollinator scarcity at high altitude. A three times larger fraction of the shoot was allocated to flowers in alpine plants (30 species, 2700m asl) compared to lowland plants (20 species, 600m asl), while leaf mass fraction did not differ between the altitudes. At high elevation, a three times smaller...
The study deals with the influence of land use and abandonment on species composition of vegetation and seed bank in grasslands and oldfields. We wanted to explore: (1)How the seed bank changes when agricultural practices cease? In convergence with proposals in the literature, we addressed in particular the following two questions that have been proposed by Symonides (1986), Pickett & McDonnell...
The embryology and seed structure of Blastocaulon scirpeum (Mart.) Giul. and Paepalanthus scleranthus Ruhland were studied in order to contribute to the embryology of Eriocaulaceae and supply data for future taxonomic studies. Both species present: anther with 4-layered wall; conspicuous endothecium with fibrous thickenings; secretory tapetum with uninucleate cells; successive microsporogenesis forming...
Morphological and functional changes of the floret whorls of Mikania urticifolia Hook. et Arn. (Asteraceae, Eupatorieae) in relation to pollination and the role of floral visitors have been observed in two Argentine localities. Flowers are dichogamous protandrous with secondary pollen presentation (“brushing” type). This feature favours cross-pollination over autogamy, but both reproductive systems...
The objective of this paper is to identify the factors that promote the invasiveness of Rhododendron ponticum L. by the means of comparative field observations. Rhododendron ponticum (Ericaceae) is an evergreen shrub with a natural distribution in the Mediterranean and Black Sea area and was introduced to the British Isles in 1763. Thenceforward, the species has been considered as a major threat to...
The needles of Pinus canariensis exhibit morphological drought adaptations, such as special stomata morphology or rigid sclerenchymatic hypodermis. In the present paper the hypothesis that drought exposure during needle elongation triggers formation of xeromorphic traits was tested. With onset of the elongation growth of the new flush, 5-year old P. canariensis seedlings were exposed to 53 days of...
In Japan, contrasting winter climate conditions between the Sea of Japan and the Pacific Ocean side have created conspicuous differences in species composition and altitudinal distribution of subalpine forests and treeline ecotones. In the Japanese Alps the altitudinal distribution of principal subalpine and treeline tree species was investigated along the slopes of four mountain ranges, two located...
Surface characteristics of primary and secondary needles of Pinus canariensis were investigated using scanning electron micro-scopy and gas chromatography to study structure and composition of epicuticular wax, cuticle micromorphology and the structure of stomata. Tubular waxes could be observed on the whole needle surface of the glaucous primary needles whereas on secondary needles they were restricted...
Effects of graminoid competition and gap size on clonal growth and reproduction of two meadow species, Lychnis flos-cuculi and Myosotis nemorosa, were studied in an oligotrophic wet meadow and in a pot experiment. In the field experiment, plant height, lateral spread, number of leaves and flowers, and clonal growth characteristics (number of secondary rosettes or shoots produced) were repeatedly measured...
Measurements of the soil pH are often used to characterize the nutritional conditions for the vegetation at a particular site, for example in ecograms describing the ecological behaviour of a (tree) species. In spite of this use and interpretation of pH measurements, certain prerequisites must be fulfilled when pH-values are to be used as an expression of the nutritional conditions for plants. Our...
The Canarian laurel forest ecosystem is composed of several co-dominant evergreen tree species including Ilex perado, I. canariensis, Myrica faya, Laurus azorica, and Persea indica. With leaves of these trees the diurnal course of stress parameters (chlorophyll fluorescence Fv/Fm, pigments, ascorbate, glutathione, gas exchange, water relations) was investigated during a mildly stressful summer day...
The alpine timberline on Mt. Teide, Tenerife, Canary Islands, occurs at about 1000 m lower elevation than that of continental mountains of similar latitude. We tested the hypothesis that edaphic and/or climatic drought are major causes for the timberline depression on this high subtropical island. Comparative measurements of soil water content, needle water status, stomatal conductance, carbon isotope...
Corydalis pumila is a perennial, spring-green tuberous geophyte mainly in deciduous forests on slopes. It is native to Central Europe, where it is rare and restricted to regions with low precipitation. This article reviews the morphology, taxonomy, distribution, ecology and population biology of this species.
Bidens frondosa is an annual weed occurring on mudflats with heteromorphic achenes. Central achenes are brown and elongated, and peripheral achenes are black and thicker. To identify differences in dormancy between the two morphs, germination of dry-stored achenes, and achenes stratified for 2, 4 and 13 weeks at 5°C, were tested at 15, 25 and 20/10°C in light for two populations. None of the achenes...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.