Flax [Linum usitatisimum L.] - A plant system for study of embryogenesis

Embryogenesis is a critical stage of the sporophytic life cycle, during which the basic body plan of the plant is established. Although zygotic embryogenesis is induced by fusion of the sperm and egg nuclei, plant cells can initiate embryo development without fertilization. For example, cultured somatic and male gametic cells can be induced to undergo somatic and microspore embryogenesis, respectively. Embryogenesis in vitro represents a powerful tool to manipulate plant development. After characterizing in situ embryo development in flax, we followed the cytological, morphological and some biochemical features of zygotic embryo development in embryo cultures. We also induced direct and indirect somatic and gametic embryo formation in flax. There is a strong indication that somatic and gametic embryogenesis is a stress response and that it is a way the plant cell realizes its survival strategy under completely changed and unusual conditions.