Histology of somatic embryogenesis in pea

Somatic embryos have been induced from pea (Pisum sativum L.) shoot apices and cotyledons of immature embryos. The former explants allowed a better embryo development than the latter. Histological studies showed that in both cases, somatic embryos have a multicellular origin. The cells surrounding the shoot apex-derived embryos contained starch grains but not the embryos themselves. The callus cells derived from immature embryo cotyledons did not accumulate starch. Hence, we suspect that numerous pea somatic embryos failed to develop because of the lack of nutrient reserves in the callus which are required to sustain full embryo development.