The vegetation of seacliffs and headlands in New South Wales,Australia

A phytosociological survey of seacliff and headland vegetation on the central and south coast of New South Wales was carried out. Analysis of the quadrat data led to the recognition of 15 communities; the occurrence of a number of other vegetation types is briefly discussed. The vegetation types fall into three major groupings: grasslands, scrub and heathland, although the coincidence between structural and floristic boundaries is poor. Ordination of the communities indicates that the major factors varying between communities are exposure and soil fertility, the grasslands and scrubs occurring on more fertile soils than the heathlands. Amongst the woody communities it is suggested that the two major groups recognized fall into different phytosociological alliances, although lack of studies of Australian vegetation limits the applicability of a conventional hierarchical classification. The true heathlands correspond closely with the alliance Leptospermion, previously recognized in Victoria. The scrub communities are assigned to a new alliance, the Westringio-Banksion integrifoliae.     

Ozone Induced Carbon Dioxide Evolution in Tobacco Callus Cultures

Callus derived from Bel–W3 and Bel–B tobacco plants when exposed to ozone turned brown as a consequence of surface cell destruction. Ozone fumigations above a threshold concentration of 0.10 μl/1 for two hoars caused an increase in the rate of tissue carbon dioxide (CO₂) evolution. The maximum increase in CO₂ evolution was about 65 percent for both the ozone sensitive Bel–W3 and resistant Bel–B callus. However, the ozone dosage required to attain maximum increase in CO₂ evolution was approximately two times greater for the resistant variety. Callus cultures that grew roots were observed to be more resistant to ozone. The addition of the antioxidant N,N'dipnenyl–p–phenylenediamine (DPPD) m the nutrient medium retarded ozone induced CO₂ evolution.     

Translation of Rabbit Haemoglobin Messenger RNA by Thalassaemic and Non-thalassaemic Ribosomes

Globin mRNA from rabbit reticulocytes can be translated equally well by human ribosomes from thalassaemic and normal reticulocytes. This implies that the defect in β-thalassaemia is not in the ability of ribosomes to translate mRNA but is probably in the mRNA itself.     

The greenhouse gas value of ecosystems

As society faces the urgent need to mitigate climate change, it is critical to understand how various ecosystems contribute to the climate, and to express these contributions in terms that are meaningful to policymakers, economists, land managers, and other nonscience interest holders. Efforts to mitigate climate change call for quantification of the full greenhouse gas (GHG) effects of land use decisions, yet we lack an appropriate metric of the full GHG implications of maintaining a given ecosystem over a multiple year time frame. Here, we propose the concept of greenhouse gas value (GHGV) of ecosystems, which accounts for potential GHG release upon clearing of stored organic matter, annual GHG flux, and probable GHG exchanges resulting from disturbance. It treats these ecosystem–atmosphere exchanges in a time‐sensitive manner, thereby providing an appropriate framework for computing of the GHG consequences of any land use decision. To illustrate this concept, we provide estimates of the GHGV of various biome types (based on data compiled from the literature), disturbance regimes, and decisions on the treatment of time. We show that natural ecosystems generally have high GHGV's, whereas managed ecosystems generally have lower or negative GHGV's; that GHGV decreases with increasing probability of disturbance, and that decisions on the treatment of time can be important, affecting some ecosystem types more strongly than others. In addition, we show how GHGV may be used to quantify the full GHG effects of land‐use or land‐cover change in a thorough and rigorous manner. Finally, we provide comparisons of GHGV to other major paradigms for valuing the GHG contributions of ecosystems, showing that – for many purposes –GHGV is the most appropriate method of quantifying the GHG services of ecosystems.