Reproduction
Gonyaulax
utilize both asexual and sexual
reproduction
© 1999 Allison Arnold and Monica
Draghic
Asexual reproduction is the dominant form of reproduction. For Gonyaulax, binary fission or mitosis can take place. In
mitosis the haploid parent cell (1n) undergoes asex and produces
two identical daughter cells. These cells each acquire half of
the theca (or cellulose plates) from
their parent, and exhibit
the full set of plates as they mature.
Because Gonyaulax contain a
dinokaryotic nucleus and spend a
majority of their life cycle in a haploid phase, binary fission
commonly takes place. With this process, a haploid cell simply
splits in half.
Sexual reproduction is not very common with these organisms but
it is utilized in the formation of cysts. The haploid adult
cells are motile and form gametes via meiosis. In induction of
the sexual phase, conjugation starts on the ventricle side of
the cell once they pair. This forms an enlarged diploid planzygote. Depending on conditions, the planzygote with either
form into a resting cyst or undergo meiosis to form a vegetative
cell. Resting cysts—or hypozygotes, sink to the bottom of the
ocean floor where they remain dormant until conditions are
favorable. The cysts are shaped as an ellipse with rounded ends
and covered by a wall of mucilaginous substance. Hypozygotes are provisioned with toxins and food
reserves for they canspend a variable amount of time in this
stage.
To learn about
the environmental relationships Gonyaulax catenella has
with other organisms, follow the link to the
interactions page!
To appreciate the life cycle of another dinoflagellate,
check out
Alexandrium tamerense
or
Galerina autumnalis
!