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EFFECTS OF LOW NITROGEN LEVELS AND VARIOUS NITROGEN SOURCES ON GROWTH AND WHORL DEVELOPMENT IN ACETABULARIA (CHLOROPHYTA) 1
Author(s) -
Adamich Marina,
Gibor Aharon,
Sweeney Beatrice M.
Publication year - 1975
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1975.tb02797.x
Subject(s) - biology , acetabularia , glycine , ammonium , nitrogen , urea , elongation , botany , nitrate , whorl (mollusc) , biochemistry , ecology , amino acid , chemistry , materials science , organic chemistry , ultimate tensile strength , metallurgy , genus
SUMMARY Nitrate, ammonia, urea, and glycine were compared as nitrogen sources for Acetabularia mediterranea. Cells grew normally in media containing nitrate or urea, while cells did not grow at all when the same amount of N was supplied as ammonium ion. The utilization of glycine remains questionable. Cells in medium without added N (NDM) increased in length and some formed reproductive caps. The whorls of vegetative cells showed considerable hypertrophy in NDM and in glycine. This hypertrophy was due to the elongation of only the first‐(a 1 ) and second‐ (a 2 ) order articles. When cut, the basal portion of cells without added N regenerated new apices with whorls. The development of these whorls was inversely proportional to the NO 2 concentration. Analyses showed that the intracellular nitrogen pool in young cells and regenerating bases was very small, about 1/10 of that of fully grown cells. Therefore we suggest that trace amounts of N contaminants in the medium supported growth and development, the uptake of which was facilitated by the hypertrophied whorls, under N‐limited conditions.