Plant embryogenesis is traditionally defined as a develop-mental process from zygote to mature embryo, which has the potential to form a complete plant (Bhojwani, 1974; Hu,2005).In dicotyledonous species, the fertilized egg or zygote usually divides according to a stereotyped patte and gives rise to an embryo that consists of an embryonic shoot,cotyledons, hypocotyls, and an embryonic root.Thus, the basic body plan of the plant is established during the embryogenesis.Interestingly, the shoot-leaf-stem structure,not including the root, is repeatedly photocopied as a basic unit throughout plant vegetative growth (Wolpert et al.,2002).