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

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Subsequent reg~neration
of short narrow thongs around the margin of
such a. re)mant resul ts in the formation of unusual fronds as Suhr (1841)
illustrated for D. mastix" A similar regenerative response occurs
where thongs are broken" Thus for some plants one of the effects of
HerpodiscU8 infection is to increase the degree of division of the
lamina. (Figs 5.12e)
The development of pa.tches of callus-like tissue (Fig, So12d)
on D. antarctica fronds. is p:cobably one of the after-effects of
infection by this parasite,
5.5 MORPHOLOGICAL VARIATION OBSERVED OVER A WIDE GEOGRAPHICAL RANGE
Eight widely separated D. antarc:tiaa samples tIIere chosen to
investigate any effect of latitude on plant morphology. Comparisons
were made between pairs of localities, which represent an attempt to
compare areas receiving the same degree of wave action, These were
Bethe11s and Woodpecker Bay on the west coast, and on the east coast:
Ohau Point and Tautuku (Area 1), Kean Point and Tautuku (Area 10)
and Oaro and Ringaringa.
Results (Fig. 5,13; 5.14, Table 5.4) showed that there was a
proportionately greater development of stipe with an increase in
latitude. For each of the above pairs, the stipes of plants in the
more northern locality were shorter and thinner than s·tipes in the
southern locality. The ratio oistipe to lamina weight increased
with increasing latitude. At Bethells stipes formed 8% of total
frond weight, whereas 600 km further south ·at Woodpecker Day, in
Westland, the stipe contribution to frond ""eight was 25~. On ·the
east coast the :ratio of stipe Height to lamina weight for samples
from Ohau Point, Godley Head (Sanks Peninsula) and 'ri'\utuku (Area
1) were 1;35, 1:23 and 1:8 respectively"
There was little difference bet~een the ~ length of D,
antarctioa from northern, central and southern sites. However,
there Nere differences in the maximum length attained by plants in
the different area.s. The longest specimen at BethelIs and Scott's
Point was 6.5 m, and of the specimens longer than 1 m, 6% exceeded
5 roo At Tautuku (1100 km further south), the longest plant v/cIs
9.3 ru, and 20% of specimens exceeded 5 w, despite the fact that the
Tautuku population was heavily infected with Herpodiscus.