Development of Marine Macroalgae

Abstract

Seaweeds include brown, green, and red algae. Their basic life cycle involves the alternation of generations between gametophytes and sporophytes. These two generations are mediated by sexual and asexual reproduction. The reproductive cells of seaweeds are released into the seawater without any support cells or tissues, easily allowing us to perform experiments and observe their different developmental stages. In this chapter, we introduce three experimental models for fertilization. First, we explore the zygotes of fucoid brown algae as a model for asymmetrical cell division. Second, we look at the fertilization of Ulva species in green algae. In this example, gametes have two flagella and move towards a light source. In contrast, zygotes have quadriflagella and move in the opposite direction, away from a light source. Last, we examine the red alga, Palmaria palmata. The life cycle of this species is unique among red algae, and we explain the procedures necessary for obtaining a small female gametophyte and inducing fertilization. These three species are easy to handle and effectively demonstrate the different fertilization processes through these experiments. In preparation for conducting these experiments, it is important to understand the maturation period for each specimen and to obtain fresh material from the field.