BIOLOGY O F SEAWEEDS O F ECONOMIC IMPORTANCE
177
6. Studies on the growth, viability and spore output of the Conchocelisphases of Porphyra
The initial penetration and growth of the Conchocelis-phase of
Porphyra purpurea was described by Drew ( 1954a) for various calcareous
substrata, including shell fragments and egg shells. Yamasaki (1954b)
observed that once the carpospore was attached to the shell surface
penetration into the calcareous substance took place after 2-3 days,
the spore membrane remaining on the shell surface. Saito (1956a)
noted that a lowering of salinity tended to inhibit carpospore germination, but subsequent growth of the filaments was less affected. After
this initial penetration " protonema "-like branches develop. Ogata
(1959a, 1960a, 1961) studied in detail the early growth of Conchocelis
filaments of P. tenera in the shell matrix. The early " protonema "like branches were observed to form " tap-root "-like filaments which
then grew vertically down into the calcareous matrix. These deeppenetrating filaments then produced laterals which were seen to grow
upwards at a slight angle until they come to lie just below the shell
surface, then branching extensively and forming a dense network of
filaments. A t first the growth of the main filament is a slow process
with shell penetration at the rate of 350p in the first 30 days. The time
taken for the filamentous mass to develop immediately below the shell
surface has some practical significance, since it is an obvious sign of the
degree of development of this phase for material growing in the culture
tanks (p. 182).
This development of the filamentous mass just below the shell
surface precedes the formation of sporangia. There is some evidence that
the pattern of the filamentous growth varies with the type of shell
material. Thus when grown in crystals of calcite the filaments tended
to grow along the cleavage patterns of the crystals, but the growth
forms of the filaments in calcite, aragonite and limestone were much the
same as those found in mollusc shells. The filaments have also been
successfully grown in cement mortar (Ogata, 1961), and any calcareous
substratum appears to be suitable, e.g. barnacle shells, coralline red
algae, and calcareous worm tubes (Drew, 1954a). These observations
indicate that a range of artificial calcareous substrata-might be used for
large-scale culture processes. Observations by Ogata (1 960b) indicate
that gravity has very little influence on the early directional growth of
the filaments. Experience has shown that the shells of a particular
appearance (e.g. those with "rough-touch") are those in which a
particularly successful establishment of the Conchocelis-phase is obtained
(Ogata, 1959b). These shells are characterized by numerous small papillate projections on the surface which presumably favour initial spore
177
6. Studies on the growth, viability and spore output of the Conchocelisphases of Porphyra
The initial penetration and growth of the Conchocelis-phase of
Porphyra purpurea was described by Drew ( 1954a) for various calcareous
substrata, including shell fragments and egg shells. Yamasaki (1954b)
observed that once the carpospore was attached to the shell surface
penetration into the calcareous substance took place after 2-3 days,
the spore membrane remaining on the shell surface. Saito (1956a)
noted that a lowering of salinity tended to inhibit carpospore germination, but subsequent growth of the filaments was less affected. After
this initial penetration " protonema "-like branches develop. Ogata
(1959a, 1960a, 1961) studied in detail the early growth of Conchocelis
filaments of P. tenera in the shell matrix. The early " protonema "like branches were observed to form " tap-root "-like filaments which
then grew vertically down into the calcareous matrix. These deeppenetrating filaments then produced laterals which were seen to grow
upwards at a slight angle until they come to lie just below the shell
surface, then branching extensively and forming a dense network of
filaments. A t first the growth of the main filament is a slow process
with shell penetration at the rate of 350p in the first 30 days. The time
taken for the filamentous mass to develop immediately below the shell
surface has some practical significance, since it is an obvious sign of the
degree of development of this phase for material growing in the culture
tanks (p. 182).
This development of the filamentous mass just below the shell
surface precedes the formation of sporangia. There is some evidence that
the pattern of the filamentous growth varies with the type of shell
material. Thus when grown in crystals of calcite the filaments tended
to grow along the cleavage patterns of the crystals, but the growth
forms of the filaments in calcite, aragonite and limestone were much the
same as those found in mollusc shells. The filaments have also been
successfully grown in cement mortar (Ogata, 1961), and any calcareous
substratum appears to be suitable, e.g. barnacle shells, coralline red
algae, and calcareous worm tubes (Drew, 1954a). These observations
indicate that a range of artificial calcareous substrata-might be used for
large-scale culture processes. Observations by Ogata (1 960b) indicate
that gravity has very little influence on the early directional growth of
the filaments. Experience has shown that the shells of a particular
appearance (e.g. those with "rough-touch") are those in which a
particularly successful establishment of the Conchocelis-phase is obtained
(Ogata, 1959b). These shells are characterized by numerous small papillate projections on the surface which presumably favour initial spore