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PREDICTING THE KINETICS OF DISSOLVED INORGANIC CARBON LIMITED GROWTH FROM THE SHORT‐TERM KINETICS OF PHOTOSYNTHESIS IN SYNECHOCOCCUS LEOPOLIENSIS (CYANOPHYTA) 1
Author(s) -
Turpin David H.,
Miller Anthony G.,
Parslow John S.,
Elrifi Ivor R.,
Canvin David T.
Publication year - 1985
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.0022-3646.1985.00409.x
Subject(s) - kinetics , synechococcus , biology , photosynthesis , cyanobacteria , term (time) , dissolved organic carbon , environmental chemistry , botany , ecology , chemistry , bacteria , physics , genetics , quantum mechanics
The blue‐green alga (Cyanobacterium) Synechococcus leopoliensis (Racib.) Komarek was grown in dissolved inorganic carbon [DIC]‐limited chemostats over the entire range of growth rates. At each growth rate, the kinetics of photosynthesis with respect to [DIC] and the maximal rate of photosynthesis (P max ) were determined. The half‐saturation constant for [DIC]‐limited photosynthesis (K 1/2 DIC ) for cells growing below 1.7 d −1 was constant (4.7 μM) whereas for growth rates between 1.7 d −1 and 2.1 d −1 (μ max ) the kinetics of photosynthesis were multiphasic with an apparent K 1/2 DIC between 1.5–2.0 mM. P max increased in a linear fashion with growth rate for growth rates below 1.7 d −1 . No trend in P max was apparent for growth rates greater than 1.7 d −1 . These kinetic parameters were used to predict a growth rate versus [DIC] relationship. Results show that the Monod relationship is a physiologically valid expression of growth as a function of [DIC] provided (K 1/2 DIC ) remains constant. The major change in (K 1/2 DIC ) as μ approaches μ max results in the conclusion that two separate and distinct Monod equations must be used to describe growth as a function of DIC over the entire growth range. These results point to a major discontinuity in the μ vs. [DIC] curve at 1.7 d −1 which corresponds to the change from high to low affinity photosynthetic kinetics. We believe these results account for the previously described deficiencies of the Monod equation in describing [DIC]‐limited algal growth.