Sexual reproduction & life cycle in Brown Algae
Except in members of Fucales, Sexual reproduction in brown algae occurs in haploid plants. In brown algae some species are isogamous, some show physiological or morphological anisogamy and also mostly show Oogamy. The sexual reproduction is brought about by multi chambered gametangia which are similar in structure to the plurilocular sporangia but behave differently; they produce gametes instead of spores. Except Fucales, all brown algae show typical alternation of sporophytic & gametophytic generations. Some show isomorphic alternation of generation (isomorphic Diplohaplontic) in which both sporophytic & gametophytic generation is morphologically similar, while in some the 2 generations are morphologically dissimilar. Generally the sporophytic plant is very large & macroscopic whereas the gametophytic plant is microscopic & very small & such life cycle is known as heteromorphic life cycle (heteromorphic Diplohaplontic).