A process of priming mature, imbibed, germinated somatic embryos of a conifer species. The process comprises fully immersing mature, imbibed, germinated somatic conifer embryos in a sterile liquid nutrient medium, bubbling an oxygen-containing gas through the liquid nutrient medium containing the germinants to form an aerated embryo-containing nutrient medium, optionally exposing the aerated germinant-containing nutrient medium to light, at least intermittently, continuing the immersion, bubbling and optional exposure to light for a period of time effective to produce at least some successfully primed conifer germinants that are adapted for subsequent planting and conversion to viable seedlings, and removing the successfully primed conifer germinants from the nutrient medium.