Does warming by open-top chambers induce change in the root-associated fungal community of the arctic dwarf shrub Cassiope tetragona (Ericaceae)?

Climate change may alter mycorrhizal communities, which impact ecosystem characteristics such as carbon sequestration processes. These impacts occur at a greater magnitude in Arctic ecosystems, where the climate is warming faster than in lower latitudes. Cassiope tetragona (L.

Growth and nitrogen fixation of legumes at increased salinity under field conditions: implications for the use of green manures in saline environments.

The use of legumes as green manure can potentially increase crop productivity in saline environments and thus contribute to the sustainability of agricultural systems. Here, we present results from a field experiment conducted in the Netherlands that addressed the efficiency of nitrogen (N) fixation by a legume at varying salinities. We grew Melilotus officinalis in an agricultural field using drip irrigation with water salinity varying in electrical conductivity between 1.

Comparing salt tolerance of beet cultivars and their halophytic ancestor: consequences of domestication and breeding programmes.

Salt tolerance of higher plants is determined by a complex set of traits, the timing and rate of evolution of which are largely unknown. We compared the salt tolerance of cultivars of sugar beet and their ancestor, sea beet, in hydroponic studies and evaluated whether traditional domestication and more recent breeding have changed salt tolerance of the cultivars relative to their ancestor. Our comparison of salt tolerance of crop cultivars is based on values of the relative growth rate (RGR) of the entire plant at various salinity levels.

Differences in proton pumping and Na/H exchange at the leaf cell tonoplast between a halophyte and a glycophyte.

The tonoplast Na(+)/H(+) antiporter and tonoplast H(+) pumps are essential components of salt tolerance in plants. The objective of this study was to investigate the transport activity of the tonoplast Na(+)/H(+) antiporter and the tonoplast V-H(+)-ATPase and V-H(+)-PPase in a highly tolerant salt-accumulating halophyte, Salicornia dolichostachya, and to compare these transport activities with activities in the related glycophyte Spinacia oleracea. Vacuolar membrane vesicles were isolated by density gradient centrifugation, and the proton transport and hydrolytic activity of both H(+) pumps were studied.

No divergence in Cassiope tetragona: persistence of growth response along a latitudinal temperature gradient and under multi-year experimental warming.

Background And Aims: The dwarf shrub Cassiope tetragona (Arctic bell-heather) is increasingly used for arctic climate reconstructions, the reliability of which depends on the existence of a linear climate-growth relationship. This relationship was examined over a high-arctic to sub-arctic temperature gradient and under multi-year artificial warming at a high-arctic site.

Methods: Growth chronologies of annual shoot length, as well as total leaf length, number of leaves and average leaf length per year, were constructed for three sites.

Ecophysiological response of Crambe maritima to airborne and soil-borne salinity.

Background And Aims: There is a need to evaluate the salt tolerance of plant species that can be cultivated as crops under saline conditions. Crambe maritima is a coastal plant, usually occurring on the driftline, with potential use as a vegetable crop. The aim of this experiment was to determine the growth response of Crambe maritima to various levels of airborne and soil-borne salinity and the ecophysiological mechanisms underlying these responses.

Do high levels of diffuse and chronic metal pollution in sediments of Rhine and Meuse floodplains affect structure and functioning of terrestrial ecosystems?

This paper (re)considers the question if chronic and diffuse heavy metal pollution (cadmium, copper, lead and zinc) affects the structure and functioning of terrestrial ecosystems of Biesbosch National Park, the floodplain area of rivers Meuse and Rhine. To reach this aim, we integrated the results of three projects on: 1. the origin, transfer and effects of heavy metals in a soil-plant-snail food chain; 2.

Heavy metal pollution affects consumption and reproduction of the landsnail Cepaea nemoralis fed on naturally polluted Urtica dioica leaves.

This study is one of the very first that investigates the effects of heavy metal pollution on food consumption and reproduction of terrestrial snails under semi-realistic field conditions. Two experiments were carried out using snails (Cepaea nemoralis) and food (Urtica dioica leaves) from different metal polluted locations and one reference location. The first experiment showed that both polluted and reference snails fed on high-metal leaves from a highly polluted location had significantly lower consumption rates than snails consuming leaves from the reference location.

Development of a proxy for past surface UV-B irradiation: a thermally assisted hydrolysis and methylation py-GC/MS method for the analysis of pollen and spores.

A method was developed for the analysis of the UV-absorbing sporopollenin monomers p-coumaric acid and ferulic acid in very low numbers of pollen. This enables the analysis of pollen or spores from cultured plants, from herbarium collections, and from sediment, soil, and peat cores. The method involves thermally assisted hydrolysis and methylation using tetramethylammonium hydroxide combined with gas chromatography and mass spectrometry.

Depletion of stratospheric ozone over the Antarctic and Arctic: responses of plants of polar terrestrial ecosystems to enhanced UV-B, an overview.

Depletion of stratospheric ozone over the Antarctic has been re-occurring yearly since 1974, leading to enhanced UV-B radiation. Arctic ozone depletion has been observed since 1990. Ozone recovery has been predicted by 2050, but no signs of recovery occur.

Physiology and ecologic relevance of salt secretion by the salt gland of Glaux maritima L.

The effects of salinity in the root medium, time, and relative humidity on the salt secretion of Glaux maritima were investigated. Both in the greenhouse and in the field increasing salinity stimulated sodium and chloride secretion, whereas the essential elements potassium, calcium, and magnesium remained at low secretion levels, which might be interpreted as efficient mineral economy. The low secretion level of potassium is remarkable, because growing on a nutrient solution containing 6 mM potassium, the concentration of the plant sap increases to 150 mM K and the secreted quantity amounts to only 2 m mol l plant sap 24 h.