BIOLOGY OB SEAWEEDS OF ECONOMIC IMPORTANCE
179
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Maturation of the Conchcelis filaments can be seen both by the
growth of the cells and the formation of sporangia and spores. Sporangium formation is slowed down in water of lowered salinity. The
output of monospores was also appreciably diminished (Yamasaki et al.,
1957). The effects of light on growth and maturation of the Conchoceliaphase have also been studied (Kurogi, 1959 ; Kurogi and Sato, 1962a,b ;
Kurogi et al., 1962; Iwasaki, 1961 ; Iwasaki and Matsudaira, 1963).
-26
25
-24
-23 .$
e
d
-
o l
-22 .o
-21 g
'c
a l
20
19
FIG. 10. Summary of general environmental conditions over the year at Matsuahime
Day length; ---.-.- Sea temperature; - - - - - - Specific gravity of sea
The vertical broken lines indicate the period of growth and maturation of the
Bay, Jepan. Drawn from date in Kurogi (1960). and Iwesaki (1961).
water.
Conchocelie-phase (mid-March to mid-September).
The observation by Drew (1956) that Conchcelis is usually found in
quantity by dredging at 32 m depth is borne out by the low value of the
compensation point mentioned above. Recent work has been concerned
with photoperiodism and its effects on the shell-boring phase, and this
work has a particular significance for the studies on seasonal behaviour
of the cultivated species described earlier. Experiments in which studies
were made on the filaments growing within the shell showed that
dark periods of 10-12 h in each day resulted in dense filaments with
179
-
-
-
-
Maturation of the Conchcelis filaments can be seen both by the
growth of the cells and the formation of sporangia and spores. Sporangium formation is slowed down in water of lowered salinity. The
output of monospores was also appreciably diminished (Yamasaki et al.,
1957). The effects of light on growth and maturation of the Conchoceliaphase have also been studied (Kurogi, 1959 ; Kurogi and Sato, 1962a,b ;
Kurogi et al., 1962; Iwasaki, 1961 ; Iwasaki and Matsudaira, 1963).
-26
25
-24
-23 .$
e
d
-
o l
-22 .o
-21 g
'c
a l
20
19
FIG. 10. Summary of general environmental conditions over the year at Matsuahime
Day length; ---.-.- Sea temperature; - - - - - - Specific gravity of sea
The vertical broken lines indicate the period of growth and maturation of the
Bay, Jepan. Drawn from date in Kurogi (1960). and Iwesaki (1961).
water.
Conchocelie-phase (mid-March to mid-September).
The observation by Drew (1956) that Conchcelis is usually found in
quantity by dredging at 32 m depth is borne out by the low value of the
compensation point mentioned above. Recent work has been concerned
with photoperiodism and its effects on the shell-boring phase, and this
work has a particular significance for the studies on seasonal behaviour
of the cultivated species described earlier. Experiments in which studies
were made on the filaments growing within the shell showed that
dark periods of 10-12 h in each day resulted in dense filaments with