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SHORT TERM UPTAKE OF NUTRIENTS BY ENTEROMORPHA PROLIFERA (CHLOROPHYCEAE) 1
Author(s) -
O'Brien Margaret C.,
Wheeler Patricia A.
Publication year - 1987
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.1529-8817.1987.tb04204.x
Subject(s) - nitrogen , nutrient , biology , botany , ammonium , chlorophyceae , composition (language) , zoology , nuclear chemistry , algae , chemistry , chlorophyta , ecology , linguistics , philosophy , organic chemistry
Rates of NH 4 + and NO 3 − uptake were determined by accumulation of 15 N in plant tissue and by disappearance of nutrient from the medium. Agreement between rates calculated by the two methods was good, averaging 82.7% (SD = 15.8%) and 91.2% (SD = 13.7%) for NH 4 + and NO 3 − uptake, respectively. An average of 93.4 and 96.0% of added 15 NH 4 + and 15 NO 3 − was recovered from the medium and /or plant tissue at the end of the incubations. Both bacterial uptake and regeneration of NH 4 + may contribute to discrepancies between NH 4 + uptake rates calculated by 15 N accumulation and disappearance of NH 4 + from the medium. The influence of tissue composition on uptake of NH 4 + , NO 3 − and PO 4 3‐ by Enteromorpha prolifera (Müller) J. Agardh was examined. For NH 4 + uptake, V max was 188 μmol NH 4 +. g dry wt −1. h −1 and K s ranged from 9.3 to 13.4 μM, but there was no correlation between kinetic parameters and tissue nitrogen content. For NO 3 − , both kinetic parameters were higher for plants with low tissue nitrogen than for plants with high tissue nitrogen. Maximum rates were 169 and 75.4 μmol NO 3 −. g dry wt −1. h −1 , and K s was 13.3 and 2.31 μM for low and high tissue nitrogen plants, respectively. Estimates of uptake in the field suggested that NH 4 + accounted for 65% and NO 3 − for up to 35% of total nitrogen uptake during the summer. Nutrient uptake rates of field‐collected plants also indicated that E. prolifera in Yaquina Bay, Oregon was not likely to have been nitrogen‐limited, but may have been phosphorus‐limited.