Density-dependent seed germination strategies in colonizing versus non-colonizing plant species.

TLDR: This study deals with an aspect of germination which has to do with both physiology and ecological strategy: how the rate of seed germination is affected by clustering of seeds into dense arrays, and the relationship between this response to density and the propensity of a species to be colonizing or weedy as opposed to being a member of an indigenous, closed plant community.

Abstract: Germination is a critical stage in the life of a plant. While much is known about the physiological processes which occur at that time, the adaptive aspects of germination strategies have received much less attention (Kozlowski 1972; Heydecker 1973). However, population biologists are aware of the importance of these strategies and have emphasized their critical role in the dynamics of plant populations (Harper 1965; Cohen 1967). This study deals with an aspect of germination which has to do with both physiology and ecological strategy: how the rate of seed germination is affected by clustering of seeds into dense arrays, and the relationship between this response to density and the propensity of a species to be colonizing or weedy as opposed to being a member of an indigenous, closed plant community. A few reports on density-dependent percentages and/or rates of germination are scattered in the literature, e.g. for pollen (Brewbaker & Majumder 1961), fungus spores (Toth 1973) and seed (Ballard 1958; Palmblad 1968). The responses of germination to greater density have included both increases (Ballard 1958; Brewbaker & Majumder 1961; Linhart & Pickett 1973; Toth 1973) anct decreases (Palmblad 1968; Toth 1973). However, comprehensive reviews of seed biology (Kozlowski 1972) and seed ecology (Heydecker 1973) do not discuss this phenomenon.