• Nsangou, Mama
  The Graduate School University of Maine
  

Somatic embryogenesis is a micropropagation method where embryonic or juvenile plant tissue can be cultured in vitro to produce somatic embryos (embryoids). The first attempt (Tremblay 1991) to propagate red spruce via this method resulted in complete failure of somatic plantlets (emblings) to survive transfer to soil. In hybrid larch, only immature zygotic embryos exhibit embryogenic competence, while mature red spruce embryos readily form embryoids.

Red spruce emblings and their zygotic counterparts germinated in vitro and ex vitro were compared for morphological and physiological characteristics. Eight month-old emblings exhibited significantly higher root:shoot ratio, growth efficiency, total chlorophyll content and net photosynthesis per projected needle area than excised-embryo seedlings. In contrast they did not differ in these traits from normal seedlings. Postgerminative development is clearly influenced by the cultural environment experienced by germinating embryos.