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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . Wiley and Nordic Society Oikos are collaborating with JSTOR to digitize, preserve and extend access to Oikos. . Energy values of tree-seeds eaten by small mammals. -Oikos 21: 52-58. Copenhagen 1970.Caloric values were determined for 19 European tree-seeds (5 conifers and 14 deciduous), which constitute a potential food for mammals. With respect to weight these seeds may be divided into four groups: very light (birch, alders), light (larch, elm, pine, spruce, black locust, lime), heavy (hornbeam, fir, ash, maples, beech, stone pine), and very heavy (hazel and oaks). The nutritive content (seeds minus coats) varies from 24 to 85 % of the whole seed dry weight.There is no correlation between the seed size and nutritive content. The caloric value of whole seeds ranged from 4.4 to 6.8 kcal/g dry wt, with the highest values for conifers, beech and hazel (6.0-6.8), while the majority of deciduous seeds have a value of 5.0-5.3 kcal/g. The energy value of nutritive material exceeded that of the whole seeds and amounted to 4.4-7.9 kcal/g dry wt. Ash-free caloric values were higher by 1-7 %. Energy values of seeds are directly correlated with the lipid content.Most of these seeds are favorite foods of rodents (voles, mice, dormice, squirrels), although some of them are also eaten by shrews, as well as deer and wild boar.

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Vaccinium myrtillus L. is a common shrub in the herbaceous layer of pine forests. In connection with resistance to pollution it has been widely used in the environmental monitoring based on heavy metal accumulations in the foliage. The present study investigates leaves of bilberry growing under influence of emissions from a Zn-Pb smelter. Determination of heavy metal levels by AAS revealed enhanced accumulations of Zn, Pb, Cd, and Fe, and the level of Zn fell into the toxic range compiled for plants of average sensitivity. To verify the significance of metal accumulations occurring in the studied plant, the concentrations of phenolics were quantified by measuring UV absorption of foliage extracts. Phenolics can be used as a potential biomarker of pollution because they participate in plant's response to accumulation of heavy metals, acting as antioxidants able to scavenge free radicals produced by metal ions. Leaves collected near the smelter contained significantly higher amounts of phenolics. Since these compounds are also responsible for ecological interactions, changes in their concentrations resulting from heavy metal accumulations might also influence other organisms in the ecosystem. To study the role of phenolics in heavy metal accumulations at the cellular level, a special fixation was applied for TEM, involving glutaraldehyde with caffeine, to precipitate phenolics in the cell. A histochemical reaction showed significantly higher electron-opacity, most probably deposits of phenolics, in cells of the leaves collected near the smelter. The subsequent degenerative changes in mesophyll of these leaves were characterized by increased contents of heterogeneous multivesicular structures, degeneration of chloroplasts, and disorganisation of membranes leading to death of the cell and necrosis.