Floral structure and pollen morphology are important characters in taxonomy of the genus Viola (Violaceae)

the pistil with stigma, stamen appendages (nectaries) and pollen heteromorphism are important diagnostic features in the genus ViolaL. The style characters were crucial in the very early classifications of this genus (Clausen 1927). We analyzed in details, using scanning electron microscopy (SEM), the microstructural characters of generative organs (style and stigma, stamens with nectaries) and pollen in representatives of three sections (Viola L., Melanium Ging., DischidiumGing.) occurring in Poland to get insights into the relatedness among far-related (different sections) and closely related (sub-sections within section) species. There is a great difference in stigma micromorphology between sections. In the section Violaflowers have style beaked at the apex, glabrous or covered by papillae and/or hairs, depending of subsection. Monotypic section Dischidiumwith one species V. biflora L. characterizes 2-lobed stigma. Cup-shaped stigma with the hole on the top and a lip below, covered with papillae and hairs on its outer surface occurs in pansies of the section Melanium. Pollen is highly heteromorphic (different pollen morphs, from three up to six apertures within one flower or even within one pollen sac) in the Melaniumsection and weakly heteromorphic mainly with three apertures in diploids of Viola and Dischidiumsections. This character is independent of the polyploidy in the Melaniumbut not in Violasection (Dajoz 1999). The flower micromorphological characters are also useful in reconstruction of closely related species origin. Based on stigma and nectaries features, two zinc violets are more similar to the alpineV. lutea, than to V. tricolor, indicated also as the ancestor (Kuta et al.2012)

TRADING-OF FRESHWATER BIODIVERSITY AND HYDROPOWER IN A UNIQUE BALKAN HOTSPOT (VJOSA RIVER WATERSHED, ALBANIA)

Inland waters and freshwater biodiversity in Albania constitute a valuable natural resource, in economic, cultural, aesthetic, scientific and educational terms. Amongst them Vjosa River watershed represents a unique feature, while its conservation and management are critical to the interests of local population, national and regional one. This review explores the special features of Vjosa River as one of the last living wild rivers in Europe. Along more than 230 kilometers in Albania it is untamed and free flowing, characterized by beautiful canyons, braided river sections and meandering stretches. Together with its tributaries, the Vjosa River creates a dynamic near-natural ecosystem, a true regional natural heritage. However, eight dams are foreseen along its course in Albania. These dam projects would destroy the unique river system. The river itself, from delta to upland flows, is migration corridor for European eel (Anguilla anguilla Linnaeus, 1758) and many other marine species

<em>Tulipa kosovarica</em> (Liliaceae), a new species of tulip from Kosovo

Shuka, Lulëzim, Tan, Kit, Krasniqi, Elez (2012): Tulipa kosovarica (Liliaceae), a new species of tulip from Kosovo. Phytotaxa 62 (1): 1-9, DOI: 10.11646/phytotaxa.62.1.1, URL: http://biotaxa.org/Phytotaxa/article/view/phytotaxa.62.1.

Alpine ecology, plant biodiversity and photosynthetic performance of marker plants in a nitrogen gradient induced by Alnus bushes

Background Alpine alder vegetation acts upon the nearby grass and dwarf shrub vegetation by the nitrogen supply from the symbiotic bacteria Frankia alni of Alnus viridis. This has been studied in two transects concerning plant distribution, plant diversity, nitrate concentration in soil and photosynthetic performance of specific marker plants. Results Away from the alder stand, a band of some meters was dominated by Calamagrostis varia which then was followed by alpine dwarf shrub vegetation. Nitrate in the soil showed a concentration decrease away from the alder stand leading to values near the detection limit in the dwarf shrub zone. Within these three zones, plant species were distributed according to their N-index, given in the ecological literature. Three dominant species, Calamagrostis varia, Rhododendron ferrugineum and Vaccinium myrtillus were examined at sites of different N-availability in the horizontal transect for their photosynthetic performance, by measuring the prompt fluorescence, the OJIP named polyphasic rise of chlorophyll-a fluorescence. All three plant species showed signs of stress in the fluorescence rise kinetics at decreased nitrate availability. These are similar to other known stress effects such as faster reduction of the primary acceptor or an electron supply limitation on the donor site of photosystem II. Conclusion Prompt chlorophyll-a fluorescence data of the examined leaves in a natural vegetation system showed the effects of a decrease in the essential nutrient nitrogen and in a manner parallel to changes in plant diversity. The selected marker plants behaved differently towards decreasing nitrogen concentrations in soil. Background Nitrogen is one of the main nutrients for plant growth and is considered to be the limiting factor for net primary production in terrestrial ecosystems [34, 35]. For high productivity in agriculture, nitrogen is supplied as fertilizer in the form of nitrate or ammonium. In natural pristine environments nitrogen fixing bacteria, free living or as root symbionts, provide bound nitrogen in nitrogen-poor soil. In the alpine shrub and grass zones the concentration of available nitrogen is often low; although various nitrogen compounds may be imported through the atmosphere by wind or rain. Alnus viridis is an important component of the tall shrub vegetation in the subalpine and alpine areas. Due to root symbiosis with the nitrogen-fixing Actinobacterium Frankia alni, the soil at these sites is enriched in plant-available nitrogen and a remarkable accumulation of biomass may be seen nearby. This suggests the presence of a nitrogen flow away from the alder zone into the neighboring grass and shrub zones. Thus, a clear change in plant composition and diversity away from the border of the Alnus tall forbs is often observed even with the naked eye

Alpine ecology, plant biodiversity and photosynthetic performance of marker plants in a nitrogen gradient induced by Alnus bushes

Abstract Background Alpine alder vegetation acts upon the nearby grass and dwarf shrub vegetation by the nitrogen supply from the symbiotic bacteria Frankia alni of Alnus viridis. This has been studied in two transects concerning plant distribution, plant diversity, nitrate concentration in soil and photosynthetic performance of specific marker plants. Results Away from the alder stand, a band of some meters was dominated by Calamagrostis varia which then was followed by alpine dwarf shrub vegetation. Nitrate in the soil showed a concentration decrease away from the alder stand leading to values near the detection limit in the dwarf shrub zone. Within these three zones, plant species were distributed according to their N-index, given in the ecological literature. Three dominant species, Calamagrostis varia, Rhododendron ferrugineum and Vaccinium myrtillus were examined at sites of different N-availability in the horizontal transect for their photosynthetic performance, by measuring the prompt fluorescence, the OJIP named polyphasic rise of chlorophyll-a fluorescence. All three plant species showed signs of stress in the fluorescence rise kinetics at decreased nitrate availability. These are similar to other known stress effects such as faster reduction of the primary acceptor or an electron supply limitation on the donor site of photosystem II. Conclusion Prompt chlorophyll-a fluorescence data of the examined leaves in a natural vegetation system showed the effects of a decrease in the essential nutrient nitrogen and in a manner parallel to changes in plant diversity. The selected marker plants behaved differently towards decreasing nitrogen concentrations in soil