Temperature and the Rate of Germination of Dormant Seeds of Chenopodium album

Abstract

Rate of germination is often used as a measure of seed vigour. However, germination may be retarded not only by low seed quality but also by dormancy. The effect of dormancy on the rate of germination of seeds of Chenopodium album was examined at a range of constant and alternating temperatures on a temperature gradient plate. Although alternating temperatures overcame much of the dormancy in seeds of C. album, the mean rate of germination (SIGMA[n]/SIGMA[Dn], where n is the number of seeds germinating on day D) was largely a function of mean temperature. The effects on rate of germination of both thermoperiod (time spent at the warmer temperature in diurnal alternating-temperature cycles) and temperature amplitude (daily maximum minus daily minimum) at sub-optimal temperatures (at which the maximum daily temperature was less than 25°C) were statistically significant. The amount of variation explained was small, however, so that the rate of germination was relatively independent of the final germination percentage at a given mean temperature. At mean temperatures over 25°C, the rate of germination decreased with increase in mean temperature.