Population differentiation in Australian Cardamine. III. Variation in germination response

Abstract

Genetic variation in germination response was observed among a series of Cardamine populations whose habitats range from sea-level to 7200 ft in southern New South Wales. This variation was closely related to altitude. In populations from below 2000 ft, germination was inhibited at high temperatures, whereas those from above 5500 ft did not germinate at low temperatures. Among populations in which germination was inhibited at low temperatures the intensity of low temperature inhibition increased with increasing altitude. The adaptive significance of high and low temperature seed dormancy in these populations of Cardamine is discussed.