Population Biology of Allium Ursinum in Northern Germany

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Abstract
The population biology of 4 A. ursinum stands was studied in a beechwood on calcareous soil and in a mixed Carpinus-Fagus woodland on a pseudo-gley soil in northern Germany from 1968-1977. Under laboratory conditions germination of A. ursinum seeds occurred after a dormancy period at 15-20.degree. C followed by stratification at 4.degree. C for at least 30 days. In the field, germination is restricted to the late winter and early spring. Development of leaves and inflorescences is also dependent on low temperature. Sexual and vegetative reproduction of A. ursinum first occurs in the 4th yr, and lasts no longer than the 8th yr. A population of A. ursinum has 4 dominant phases of mortality: at the embryo stage, autolysis of seeds during dormancy and stratification, mortality of individuals as they move to lower soil layers by contractile roots, and the phase of aging (after 7-8 yr). The existence of pure stands of A. ursinum is discussed in relation to the concept of Allium as an r-strategist among K-strategists, and to possible allelochemical and mechanical effects of the dying leaves. The mineral-element content of different organs of A. ursinum is related to the life cycle of the individual plant. The significance of high nitrate concentration in the leaves of Allium in spring is discussed.