During embryo development (embryo-genesis), the structural axis of the new sporo-phyte body, apical meristems and patterns of tissue systems are established. This development may occur within a few hours following fertilization or may be delayed by days, weeks or months . Embryo development can be divided into three general phases: (i) establishment of the embryonic axis, shoot and root apices, embryonic tissue and organ systems; (ii) embryo maturation, including accumulation of storage reserves; and (iii) developmental arrest, embryo desiccation and metabolic quiescence