No abstract

Plant growth largely depends on microbial community structure and function in the rhizosphere. In turn, microbial communities in the rhizosphere rely on carbohydrates provided by the host plant. This paper presents the first study on ozone effects in the plant-rhizosphere-bulk soil system of 4-year-old beech trees using outdoor lysimeters as a research platform. The lysimeters were filled with homogenized soil from the corresponding horizons of a forest site, thus minimizing field heterogeneity. Four lysimeters were treated with ambient ozone (1 x O3) and four with double ambient ozone concentrations (2 x O3; restricted to 150 ppb). In contrast to senescence, which was almost unaffected by ozone treatment, both the photochemical quantum yield of photosystem II (PSII) and leaf gas exchange were reduced (11 - 45 %) under the elevated O3 regime. However, due to large variation between the plants, no statistically significant O3 effect was found. Even though the amount of primary metabolites, such as sugar and starch, was not influenced by elevated O3 concentrations, the reduced photosynthetic performance was reflected in leaf biochemistry in the form of a reduction in soluble phenolic metabolites. The rhizosphere microbial community also responded to the O3 treatment. Both community structure and function were affected, with a tendency towards a lower diversity and a significant reduction in the potential nutrient turnover. In contrast, litter degradation was unaffected by the fumigation, indicating that in situ microbial functionality of the bulk soil did not change.

A lysimeter study was performed to monitor effects of elevated ozone on juvenile trees of Fagus sylvatica L. as well as on the plant-soil system. During a fumigation period over almost three growing seasons, parameters related to plant growth, phenological development and physiology as well as soil functions were studied. The data analyses identified elevated ozone to delay leaf phenology at early and to accelerate it at late developmental stages, to reduce growth, some leaf nutrients (Ca, K) as well as some soluble phenolics (hydroxycinnamic acid derivatives, total flavonol glycosides). No or very weak ozone effects were found in mobile carbon pools of leaves (starch, sucrose), and other phenolic compounds (flavans). Altered gene expression related to stress and carbon cycling corresponded well with findings from leaf phenology and chemical composition analyses indicating earlier senescence and oxidative stress in leaves under elevated ozone. Conversely in the soil system, no effects of ozone were detected on soil enzyme activities, rates of litter degradation and lysimeter water balances. Despite the fact that the three reported years 2003-2005 were climatically very contrasting including a hot and dry as well as an extremely wet summer, and also mild as well as cold winters, the influence of ozone on a number of plant parameters is Water Air Soil Pollut: Focus (

This study examined the occurrence, relative abundance and condition of platypuses in the upper catchment of the South Esk River, in north-east Tasmania, Australia, and the impact of past forestry activities on the occurrence of platypuses in first order headwater streams. The main trapping sites were in twenty first order streams, eight second-fourth order headwater streams and one fifth order stream reach. Additional trapping was also undertaken in the South Esk River and farm dams. Sites were trapped during late spring/mid summer and early autumn. A total of 78 individuals were caught in the study area. Platypuses were caught at all sites trapped in the second-fourth order and fifth order stream reaches and in nine of the twenty first order streams. Catch success was greatest in the fifth order stream reach and lowest in the first order streams. There was a trend toward a higher proportion of juvenile/subadult males in the lower order stream sites. For the higher stream orders, a higher proportion of individuals was caught during the summer, however for the first order streams, a higher proportion was caught during the autumn trapping period.Information collected on the body mass, body length and condition of individuals indicated smaller individuals with a higher tail fat index in the lower order streams.There was a trend toward a lower occurrence of platypuses in the first order streams, which had been disturbed 15 years previously by forestry operations compared to first order streams with relatively undisturbed catchments. Differences in occurrence of platypuses were related to differences in the 'instream' and riparian characteristics of disturbed streams compared to undisturbed streams. Headwater streams form a large proportion of a river system. Although they provide more marginal habitat for the platypus than larger river reaches, their disturbance may be an important land management issue in the conservation of this species, particularly in river catchments where the species is impacted by other environmental changes or disease.

These results demonstrate that delayed treatment with clopidogrel and everolimus-representative of a clinical setting-prevents the progression of transplant arteriosclerosis and impairs humoral immunity in this experimental model.