Abstract
Owing to the characteristic growth of Conchocelis filaments perforating the shells, discrimination of intact, injured and dead states in them has so far been in great difficulties. A particular advantage was found in the use of tetrazolium salt as a viability indicator. Triphenyl-tetrazolium chloride (TTC) used in properly conditioned treatments was reduced by the filaments so as to produce red pigmentation by formazan. The gradation in the reduction reflected the intact, injured and dead states very sharply, no reduction occuring in the dead filaments.
Recommendable conditions for viability test were found as the following:
a) The final TTC concentrations of 1mg./cc. in twice diluted sea water is sufficient for use;
b) Incubation at 30°C. favours the reaction greatly and lower temperature is disadvantageous:
c) Illumination (1500-2000 lux) and evacuation do not favour the reaction so much, and is unnecessary in most cases.
Non-enzymatic photochemical reduction of TTC, especially by ultraviolet irradiation was vigorous. But such a reduction could be obviously distinguished and excluded from the vital reduction.
From these result: it was concluded that the TTC test gives quite reliable criteria, and should be recommended to practical nursing and cultivation of Porphyra tenera and Conchocelis.
