Sexual Sporulation in the Chytridiomycota
- During sexual sporulation ZOOSPORES are formed and released from ZOOSPORANGIA just as they are during asexual sporulation.
- But during the sexual phase of the life cycle, zoospores from different compatible zoosporangia are attracted to one another - they come together in pairs and FUSE to form a MOTILE, BIFLAGELLATE, DIPLOID ZYGOTE.
- The zoospores are behaving like motile gametes - for this reason we call the zoosporangia from which they originate GAMETANGIA.
- We regard the zoospores (gametes) as being of opposite sexes, although in many species they are morphologically indistinguishable from one another.
- Eventually, the biflagellate ZYGOTE stops swimming, loses its flagella, rounds up, develops a thick wall and becomes converted into a RESTING ZOOSPORANGIUM which is capable of surviving adverse environmental conditions.
- When environmental conditions are once again favourable for the species, MEIOSIS occurs within the resting zoosporangium and HAPLOID ZOOSPORES are released.
- These haploid zoospores will develop into the HAPLOID SOMATIC FORM of the species.