Gametogenesis, gametes and zygotes: An ecological perspective on sexual reproduction in the algae

Abstract

Ecological aspects of sexual reproduction in freshwater and marine algae are reviewed in the context of reproductive seasonality, gamete release, pheromones, fertilization success, polyspermy, parthenogenesis, and the dispersal of zygotes. Fertilization success in freshwater and marine macroalgae is higher than previously assumed, and the biological and physical variables that contribute to this are reviewed and analysed. These variables include synchronous release of gametes, plant architecture, immobilization of female gametes, cytological specializations (e.g., in the spermatia of some red algae), agglutinins, and a number of important aspects of water motion. Little is known about fertilization success in unicellular algae, but various aspects (gametogenesis, resting zygotes) of reproduction in such algae are considered. The review concludes with questions that should be addressed in future studies; a number of these require more attention to hydrodynamic variables.