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

143
released
in each of the three
so it seems
that the
of
this
are released
of sea conditions.
Resul ts
obta.ined for D. samples were not as clear cut" Oris
would not release in any treatment. of the remaining 11
that released in both calm treatments, 7 released in the
treatmen~Cf and of 2 released just slightly" These results
that for D. antaPcticQ~ conditions are more conducive
than conditions to heavy release. It difficult to find
any other likely reason \"Ihy D. 1, 2, 8 and 9
released heavily in calm water,but would not release at all when
conditions were
All that Can be stated certainty is that for both
were released in both artificial calm and rough sea conditions.
6.4
Sexes were easiest to in winter when plants were
After
had lain on the shore for several hours
the lllales exuded a whitish slime and the females a dark
slime. The sexes occur in numbers for both
In a sample of 188 D. antaPctioQ from Area 1, Taut:uku,
collected in 1972, 47% 'l>lere females, and in a of
136 D. lana collected at various times at Tautuku, 42% were
females. There was no evidence that one sex occurred more commonly
than the other at different levels on the shore. In of D.
antarotica laminae collected along the bottom and top of the D,
belt on Second I Tautuku, the sex ratio ~las approxi-
same
1
1. Both sexes we:ce frequently found attached to the
holdfast.
6.5
Individual
one crop of
each year,
with the early
of the next season's crop
visible in outer cortical cells as soon as, or o.iter the
conceptacles of the season are
The of a1 terna ting dark and ligh t s of cells
in the outer cortex is
and these are related to the
layering of described by (1953) •
Both are annual phenomena, and may be used to estimate >.:he minimum
age of