Makrospóry

Makrospóry are large spores produced by heterosporous plants, which are plants that produce two distinct types of spores. These larger spores are the female gametophytes, also known as megaspores. They develop within a structure called the megasporangium. Upon germination, a megaspore develops into a female gametophyte, which typically contains one or more archegonia. Each archegonium houses an ovum, the female reproductive cell. The production of megaspores is a key feature in the evolutionary lineage leading to seed plants, as it represents an early step in the development of protected female gametophytes and eventually the ovule. In ferns and some algae, megaspores are released from the megasporangium, while in seed plants, they remain retained within the megasporangium and are enclosed by maternal sporophyte tissue, forming the ovule. The development of megaspores and their subsequent transformation into female gametophytes is a critical event in plant reproduction, enabling the formation of seeds and the continuation of the species.