Beneficial effects of moist chilling on the seeds of black spruce (Picea mariana [Mill.] BSP)

Moist chilling (cold stratification) is well-known as a simple and effectiv e means of overcoming physiological seed dormancy and enhancing germination of many temperate tree and shrub species. However, the apparent activation of intracellular repair mechanisms in non-dormant black spruce (Picea mari ana) seeds following moist chilling, has not previously been reported. The present contribution records the beneficial effects of moist chilling after accelerated ageing (40 degrees C/98 % relative humidity) for 3-10 d of bla ck spruce seeds. This treatment was maximally effective after 7 d of accele rated ageing, increasing germination from 43 to 61 %. Ultrastructural exami nation of embryo cells indicated that intracellular activation occurred dur ing moist chilling even when seeds had not been subjected to accelerated ag eing, and that the increasing levels of damage accumulating over the 3-7 d period of ageing were substantially reversed during subsequent moist chilli ng. The results of cold stratification of non-dormant seeds are discussed i n terms of the value of this practice in nursery seedling production from s eeds that are of less than the highest quality. (C) 2000 Annals of Botany C ompany.