In Citrus, apomictic embryos arise from which type of tissue?

In Citrus, apomictic embryos develop specifically from the maternal sporophytic tissue in the ovule. Apomixis is a form of asexual reproduction that bypasses the typical fertilization process, allowing the formation of embryos directly from maternal tissues. This means that the embryo can form without the contribution of paternal genetic material, making it genetically identical to the mother plant.

This process occurs through structures such as the nucellar tissue or the integuments of the ovule, which can give rise to embryos under certain conditions. Since these embryos arise from the maternal sporophytic tissue, they retain a direct lineage to the mother plant, which is a key characteristic of apomixis.

The other types of tissues mentioned do not contribute to the formation of apomictic embryos. Embryonic tissue in seeds is involved in the development of sexually produced embryos following fertilization, while male gametophyte tissue relates to pollen grains and does not participate in embryo development in the case of apomixis. Fetal tissue in fruit is not relevant to embryo formation, as it develops post-fertilization. Thus, the correct answer highlights the unique and asexual reproductive strategy observed in apomictic processes in plants like Citrus.