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

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CHAPTER SlX
REPRODUCTION AND PHENOLOGY
6.1 INTRODUCTION
'J.'he anatomy of conceptCi_cles -in D. antaY'ctica and both D.
antarctica and D. -wiUana was described by Herriott: (1923) and Naylor
(1953-) " My own investigations into conceptacle anatomy have, in
the main, led me to agree with these authors. Little information
has been published about the development of conceptacles, reproductive
periodicity and environmental factors \-Thich might influence gamete
release. These topics are therefore considered here.
6.2 SEQUENTIAL DEVELOPMENT AND MATURATION OF CONCEPTACJ~S
Various stages in the development of conceptacles are illustrated
in Table 2,2. They form in the outer cell layers of the cortex ",here
there is localised branching in the rows of rectangUlar cells. These
areas often appear as little more than slight irregularities in the
strict arrangement of the rows of cells o No conceptacle initial
cell, or cells, could be found in the meristoderm 1 or outer cortex of
either fresh or preserved material. ~~is does not necessarily mean
that an initial cell is absent, however, because large amounts 6~·
mucilage obscured much of the detail in even the thinnest sections
examined (2.5 vm thick).
The appearance of a small oval or flask-shaped cavity
(initially little bigger than two or three outer coY~~ical cells) was
the first clearly discernible stage in the formation of ne'\-J
conceptacles' (stage A Tab. 20 20 Fig. 6.1a,b). These apparently
contain mucilage, and stain deeply (blue I"ith toluidine blue. In
fresh unstained material they are yellowish, and stand ou-t amongs-l:
Meristoderm is used in the sense of Fritsch (1945) and Naylor
(1953). See Chapter 5.