carposporophyte

Carposporophyte is the diploid generation in the life cycle of most red algae (Rhodophyta). It develops from the fertilized zygote on the female gametophyte (carpogonium) after fertilization and typically remains attached to the host tissue as a distinct, often parasitic structure.

Within the carposporophyte, carposporangia form and produce carpospores, which are diploid cells. The carpospores are released and germinate to establish the diploid sporophyte (the tetrasporophyte), which in turn bears tetrasporangia. Meiosis in these tetrasporangia yields haploid tetraspores that grow into new male and/or female gametophytes, completing the cycle.

Morphology and occurrence of carposporophytes vary among taxa. They can be filamentous or more elaborate and may be embedded within the female thallus or project as a protrusion. Carposporophytes are generally non-photosynthetic and obtain nutrients from the surrounding female tissue.

Significance: The carposporophyte is a defining feature of the red algal life cycle, serving as the bridge between fertilization and the formation of the diploid sporophyte. Through the production of carpospores, it enables propagation and genetic continuity of the species across generations.