抄録
Porphyra tenera was cultured for a period of 1 to 6 days in the media containing NH4C1, NH4NO3, urea or NaNO3 as the nitrogen source (0.01% as N), and the changes in the amounts of the total nitrogen, extractive nitrogen and extractive amino acids (alanine, aspartic acid and glutamic acid) in the frond were determined.
The results are shown in Tables 1 and 2, and are summarized as follows:
(1) With NH4-salts as the nitrogen source, the total-N, ext.-N and alanine increased very rapidly, and 20 to 30% of the increment of ext.-N was accounted for by alanine. The increase of aspartic and glutamic acids was not so marked as that of alanine.
(2) With urea, the absorption of nitrogen was slow for the first 4 days, turned to be very rapid thereafter, and almost the same amount of nitrogen was absorbed in 6 days as in the case when NH4NO3 was used as the nitrogen source. It is noted, however, that the glutamic acid content increased markedly during the first 2 days.
(3) With NaNO3, the total-N content did not increase so rapidly as with NH4-salts, but there was considerable increase in the contents of the three amino acids.
(4) It seems that in Porphyra tenera the amount of extractive alanine is more easily affected by the nitrogen condition of the environmental sea water than that of aspartic or glutamic acid.
