Phenolic compounds in the covering tissues of the canola embryo during embryogenesis
During maturation of the canoly embryo the tissues covering it produce phenolic compounds. The phenolics are located in the epidermis of the integumentum externum and in the innermost layer of the integumentum internum. At the next stage of heart- and torpedo-shaped embryos phenolics are in the stellar cells and the endosperm. In green seeds when the integumentum internum and the stellar cells gradually desappear, the remaining tissues contain phenolics in the cell walls. Impregnation of the cell walls with phenolics is visible in the only remaining layer of cells (stellar cells) of the mature black seed. These compounds constitute a barrier between the embryo and its environment.