Ecological life cycle and physiological ecology of seed germination of Arabidopsis thaliana

Abstract

Field observations were made on the ecological life cycle of the winter annual Arabidopsis thaliana (L.) Heyn. from a population in central Tennessee, and a detailed laboratory study was conducted on the physiological responses of the seeds to temperature in light (14-h photoperiod) and constant darkness. At maturity and dispersal (late April and early May), seeds germinated to high percentages only at low temperatures (5–10 °C) in light. With storage from May to September and October (1) the maximum temperature for germination in light increased from 15 to 30 °C and in darkness from 10 to 20 °C and (2) the optimum temperature for germination in light increased from 5 to 15–20 °C and in darkness from 5 to 5–10 °C. During the spring–summer period seeds were dormant at temperatures simulating those in the natural habitat. In September and October, seeds in light germinated to high percentages at simulated September and October temperatures but did not germinate in darkness at the September temperatures and germinated poorly at October temperatures. Regulation of germination so that it occurs in early autumn allows A. thaliana to persist in a summer-arid habitat.