| abstract |
Desiccated mature gymnosperm somatic embryos, preferably coniferous somatic embryos having a moisture content of less than about 55%, are prepared by water stressing immature embryos in a medium comprising a metabolizable carbon source and a suitable growth regulator influencing embryo development, for a period of time and under conditions sufficient to yield mature viable somatic embryos having a moisture content in the specified range. The water stressing should may be environmental, as by controlled declining relative humidity. Or a suitable osmotic or non-osmotic water stress agent can be used. The use of a non-permeating osmotic water stress agent such as polyethylene glycol of molecular weight at least about 1,000 is preferred, in which case the water stress should simulate a non-osmotic water stress. An example of a suitable preferred growth regulator is abscisic acid. |