Measurements of the statistical characteristics of umbra and sunflecks at different depths inside a willow coppice — Salix viminalis and Salix dasyclados — were carried out at Tartu Observatory, Tõravere, Estonia, in 1997. A new instrument, the sunfleck indicator, constructed by M. Sulev, was used. This instrument, moving perpendicularly to rows in the horizontal direction, counts the number an...

Botanisches Institut der Universität zu Köln, Gyrhofstraße 15, D-5000 Köln 41 Z. Naturforsch. 40c, 599—605 (1985); received May 6, 1985 Epicuticular Waxes, Alpine Plants, Ecophysiology, Relation to Altitude, Ultrastructure Epicuticular waxes were extracted and analysed from leaves of 7 different high alpine plant species, with 3 species harvested at different altitudes: Salix herbacea (1950 m, ...

Biomass produced from dedicated plantations constitutes a source of renewable energy and is expected to play an important role in several countries in the coming decades. The cultivation of woody crops such as willows therefore raises several environmental issues. In North America, several native willows are potentially interesting for biomass producers. Willow trees are diverse but few species...

Population sex ratios of many dioecious plants in nature are biased. This may be attributed to sexually different resource demands and adaptive capacity. In male-biasedPopulus, males often display stronger physiological adaptation than females. Interestingly, Populus and Salix, belonging to Salicaceae, display an opposite biased sex ratio, especially in nutrient-poor environmental conditions. D...

An earlier identified major quantitative trait locus for resistance towards the willow leaf rust fungus Melampsora larici-epitea in a Salix viminalis x (S. viminalis × S. schwerinii) population was used to identify potential resistance genes to the rust pathogen. Screening a genomic bacterial artificial chromosome library with markers from the peak position of the QTL region revealed one gene w...

Western European coastal sand dunes are highly important for nature conservation. Communities of the creeping willow (Salix repens) represent one of the most characteristic and diverse vegetation types in the dunes. We report here the results of the first kingdom-wide fungal diversity assessment in S. repens coastal dune vegetation. We carried out massively parallel pyrosequencing of ITS rDNA f...

In semiarid western North American riparian ecosystems, increased drought and lower streamflows under climate change may reduce plant growth and recruitment, and favor drought-tolerant exotic species over mesic native species. We tested whether elevated atmospheric CO₂ might ameliorate these effects by improving plant water-use efficiency. We examined the effects of CO₂ and water availability o...

Symbiotic fungi's role in providing nitrogen to host plants is well-studied in tundra at Toolik Lake, Alaska, but little-studied in the adjoining boreal forest ecosystem. Along a 570 km north-south transect from the Yukon River to the North Slope of Alaska, the 15N content was strongly reduced in ectomycorrhizal and ericoid mycorrhizal plants including Betula, Salix, Picea mariana (P. Mill.) B....

The interaction between plants and microorganisms, which is the driving force behind the decontamination of petroleum hydrocarbon (PHC) contamination in phytoremediation technology, is poorly understood. Here, we aimed at characterizing the variations between plant compartments in the microbiome of two willow cultivars growing in contaminated soils. A field experiment was set-up at a former pet...

The use of Bombus terrestris L. commercial colonies for outdoor and greenhouse crop pollination is currently widespread. Colony breeding includes bumblebee feeding, mostly by using the honeybee pollen loads of diverse palynological composition. Because the chemical content of pollen is highly variable, the choice of commercial blend should not be random but has to be carefully selected to ensur...