High-efficiency somatic embryogenesis and morphohistology and histochemistry of somatic embryo development in Larix leptolepis Gordon

A high-efficiency somatic embryogenesis protocol of Japanese larch (Larix leptolepis Gordon) has been established in our investigation. Calli were induced from immature zygotic embryos of female cones of L. leptolepis and then subcultured regularly on to a modified Gupta and Durzan (DCR) basal medium for 5 years. Embryogenic tissues showed distinct morphological changes during somatic embryo development when they were transferred to a maturation medium supplemented with abscisic acid (ABA) compared with the morphology in a medium lacking ABA. Histological observations indicated that polyembryony was a characteristic feature during early embryogeny and somatic embryos at later stages showed normal histodifferentiation. In addition, histochemical analysis revealed that abundant starch granules and proteins accumulated in mature embryos, indicating that they played important roles in the development and regeneration of normal plantlets from somatic embryos on hormone-free germination media