A biological study of Durvillaea antarctica (Chamisso) Hariot and D ...

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Al though lim i ted by the fae t th at no conccptacle in i tia 1 ce 11
could be found, development of conceptacles in both species is quite
clearly endogenous, conceptacles develop more or less simultaneously
over the lamina. Within the conceptacles, it is possible to find
oogonia at various stages of development. As ova are released,
new oogonia are formed, and it is highly probable that, once ripe,
an individual conceptacle will produce ova until the end of the
releasing pe:ciod tllhen a layer of cells grows over the ostiole.
The releasing periods of both species are
similar,
although that of D, liJiUana lags several weeks behind that of D.
antamtica, In the South Island gametes are released from late
autumn (April) to early spring (August-September) with a peak
release period in midwinter. There is evidence, however, of annual
variation in the length of the reproductive season, There-is also
sufficient evidence to suggest that the length of the releasing
period in the far north is more contracted than in the south.
Water temperature can exert some influence on the rate of
release of ova, and possibly fertilization and early growth.
D. antarctica and D, liJiZZana will release in air, and if kept
permanently immersed. They also release in both calm and rough
condi tions.