Читать книгу Principles of Plant Genetics and Breeding - George Acquaah - Страница 361

Sometimes, especially in crosses between different plant species, the embryo formed after fertilization in wide crosses fails to develop any further. The breeder may dissect the flower to remove the immature embryo. The embryo is then nurtured into a full plant by using the tissue culture technology. This technique is called embryo rescue. The fertilized ovary is excised within several days of fertilization to avoid an abortion (due to, e.g. abnormal endosperm development). Normal embryogenesis ends at seed maturation. The development of the embryo goes through several stages with certain distinct features. The globular stage is undifferentiated, while the heart stage is differentiated and capable of independent growth. The torpedo stage and cotyledonary stage of embryo development follow these early stages. Prior to differentiation, the developing embryo is heterotrophic and dependent on the endosperm for nutrients. Excising the embryo prematurely gives it less chance of surviving the embryo rescue process. Just like all tissue culture work, embryo rescue is conducted aseptically and cultured on the medium appropriate for the species.