The effect of elevated CO2 and different levels of nitrogen on the partitioning of nitrogen between photosynthesis and a constitutive nitrogen-based secondary metabolite (the cyanogenic glycoside prunasin) was examined in Eucalyptus cladocalyx. Our hypothesis was that the expected increase in photosynthetic nitrogen-use efficiency of plants grown at elevated CO2 concentrations would lead to an effective reallocation of available nitrogen from photosynthesis to prunasin. Seedlings were grown at two concentrations of CO2 and nitrogen, and the proportion of leaf nitrogen allocated to photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), protein and prunasin compared. Up to 20% of leaf nitrogen was allocated to the cyanogenic glycoside, although this proportion varied with leaf age, position and growth conditions. Leaf prunasin concentration was strongly affected by nitrogen supply, but did not increase, on a dry weight basis, in the leaves from the elevated CO2 treatments. However, the proportion of nitrogen allocated to prunasin increased significantly, in spite of a decreasing pool of leaf nitrogen, in the plants grown at elevated concentrations of CO2. There was less protein in leaves of plants grown at elevated CO2 in both nitrogen treatments, while the concentration of active sites of Rubisco only decreased in plants from the low-nitrogen treatment. These changes in leaf chemistry may have significant implications in terms of the palatability of foliage and defence against herbivores.
The amino acid similarity matrix (A), the amino acid identity matrix (B) and the cDNA sequence identity matrix (C) comparing the four full length sequences. (XLSX 8Â kb)
Functionality, as measured by activities of daily living (ADL), is the most important predictor of the cost of nursing home care. Data from a field-test version of the federally mandated Minimum Data Set (MDS) were examined using analysis of variance (ANOVA) and recursive partitioning methods to determine the relationships between ADL limitations and nursing cost (wage-weighted nursing time) among nursing home residents (n = 6,663). From this analysis, an index based on limitations in four ADLs was created. The developed ADL index is a readily determined measure of functional status useful in allocating nursing staff within nursing homes and in comparing the functional status of groups of residents, explaining 30 percent of variance in nursing costs among nursing home residents.
The paucity of evidence on eucalypt browsing by common brushtail and common ringtail possums suggests that ringtails preferentially eat foliage from trees within the subgenus Monocalyptus. In contrast, brushtails eat less eucalypt foliage than do ringtails and prefer trees from the subgenus Symphyomyrtus. Trees from these subgenera differ in their defensive chemicals. Both contain tannins but it appears that only the symphyomyrts synthesise formylated phloroglucinol compounds (FPCs). We fed possums foliage from several individual Eucalyptus rossii and E. consideniana, both monocalypts, to avoid the confounding factor of FPCs, and examined the effects of blocking tannins by dipping foliage in polyethylene glycol (PEG). Ringtails and brushtails differed in their abilities to eat foliage from these eucalypts. The ringtails ate much more than did the brushtails and showed a small (about 10%) but significant increase in feeding in response to PEG. The brushtails were reluctant to eat foliage from either eucalypt species but doubled their intake when leaves were coated with PEG. Even so, they still did not eat enough to meet maintenance requirements for energy and nitrogen. Neither ringtails nor brushtails preferred foliage from any individual E. rossii tree, suggesting that all trees were equally defended. However, brushtails preferred foliage from some E. consideniana to others. Monocalypt tannins are clearly important barriers to feeding in brushtail possums, but further research with higher doses of PEG will confirm whether they are the only deterrent chemicals in monocalypt foliage.
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