Autecological studies on Audouinia capitata 6. Embryo nutrition

Autecological studies on Audouinia capitata (Bruniaceae). 6. Nutritional aspects of the developing ovule
J.H.de Lange, J.J.A.van der Walt & C.Boucher 1993 South African Journal of Botany 59 168-177 https://doi.org/10.1016/S0254-6299(16)30750-5

The present investigation provides a basis for studies about morphological and nutritional aspects involved in late abortion of embryos and nutrient-linked, pre-emergent mortality of seedlings in this threatened species. The nucellus is digested completely during megagametogenesis and the integument likewise during embryogenesis, except for a diminutive testa. Mass starch deposition is found in the mature embryo sac. Involvement of the persistent synergid in nutrition of the zygote and the 2-celled proembryo until the fifth week, is suggested. This function is taken over by the suspensor which initially channels integumentary reserves to the developing proembryo. From the eighth week, spherical protein bodies are evident in the endosperm. At this stage, the embryo proper is still surrounded by free nuclear endosperm, and the suspensor of the linear proembryo mobilizes, in addition to integumentary reserves, also adjacent cellular endosperm as well as the micropylar layer of cellular endosperm. The embryo proper of the more advanced stages mobilizes nutrients directly from the adjacent cellular endosperm. The seed enters dormancy at the heart-shape stage of embryo development.

Publicado el junio 16, 2022 08:06 TARDE por tonyrebelo