Double fertilization is a unique feature of angiosperms.
Angiosperms are flowering plants, which are characterized by their flowers and fruits. Double fertilization is a process that occurs during the formation of seeds in angiosperms, where two sperm cells from the pollen tube fertilize two different cells in the female gametophyte. One sperm cell fertilizes the egg cell, forming a zygote that will develop into an embryo, while the other sperm cell fertilizes the central cell, forming the endosperm, which is a nutrient-rich tissue that provides nourishment to the developing embryo.
This unique process of double fertilization is not found in bryophytes, pteridophytes, or algae. In these other groups of plants, fertilization occurs through a single sperm cell that fuses with the egg cell, forming a zygote. The endosperm is formed either by cell division of the zygote or by the fusion of the sperm cell with a separate cell in the female gametophyte.
Therefore, double fertilization is a key characteristic that sets angiosperms apart from other groups of plants. It allows for the efficient use of resources and the production of seeds with a high nutrient content, which contributes to the success and diversity of angiosperms in many different environments.