抄録
In order to get knowledge on the shedding of Undaria, Ecklonia and Eisenia (Laminariaceae) in nature, their sporophylls were cultured in running sea water and the amount of spores, shed was successively observed.
Shedding season of Undaria is supposed to begin when the sea water temperature rises to 14°C. in spring (see Table 4).
Shedding of these algae occurs daily in mass in 1-2 hours, chiefly during from 9 a.m. to 6 p.m. The shedding amount rises to an enourmous level on some days, likely on every 4th-5th day (106-107 spores per gr. in Undaria, 105-106 in Ecklonia and Eisenia), while in other days it stays at much lower level (104-1O5 per gr.). Besides above mentioned, shedding occurs fast in all the time in a day in a small quantity (less than 104 per gr. hrs.) (see Fig. 1, Table 1-3). It is supposed that shedding of these algae will occur in the same way also in nature.
In dark cultures there seemed no difference in the manner of shedding at least for 3 days, from in day-light cultures.
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To get spores of these algae, it is a custom to immerse sporophylls into sea water after drying for a few hours. In compared with the shedding in running sea water, this treatment seems not to be effective to enlarge the amount of shedding, but seems to have only some effect to hasten the time of shedding (see Table 3).
