Events following ABA treatment of spruce somatic embryos

Abscisic acid (ABA) is involved in various physiological processes in plant growth and in the development of embryos and the maturation of seed. There is still much to learn about the influence of ABA on regulation of gene expression during plant and seed development. Perhaps not surprisingly, ABA has a major role in the stimulation of somatic embryo maturation in several conifer species, especially spruces. In spite of this, our knowledge of the effects of exogenous ABA is incomplete, for example the effect of ABA concentration on its uptake and fate has rarely been investigated during somatic embryo culture, and our knowledge of molecular events in conifer somatic embryo development is very scant. The intent of this review is to summarize some of the recent research in spruce somatic embryo development related to the use of ABA and to the consequence of its use.