TY - JOUR
AU - COLMAN,, BRIAN
AB - Abstract The carbon dioxide compensation point of the unicellular green alga, Chloretla saccharophila, was determined in aqueous medium by a gas chromatographic method. Compensation points decreased markedly from 63 cm3 m−3 at an external pH of 4.0 to 3.2 cm3 m−3 at pH 8.0 and were not affected by the O2 concentration of the medium. The calculated CO2 concentration required to support the half-maximum photosynthetic rate of the algal cells ranged from 6.0 mmol m–3 at an external pH of 60 to 1.5 mmol m−3 at pH 8.0 and these values were not affected by O2 concentration. The Km(CO2) of nbulose-l,5-bisphosphate carboxylase isolated from cells grown either at pH 4.0 or pH 8.0 was determined to be 64 mmol m−3. These results indicate that loss of CO2 by photorespiration does not occur in C. saccharophila cells at acid pH and the disparity between the apparent affinity for CO2 of the intact cells and that of the carboxylase indicates the operation of a ‘CO2 concentrating mechanism’ in this alga at acid pH. Acidophilic alga, bicarbonate transport, Chlorella saccharophila, compensation point, CO2 affinity, PH, RuBP carboxylase This content is only available as a PDF. Author notes 1Present address: Department of Botany, University of Thessaloniki, GR-540 06 Thessaloniki, Greece. © Oxford University Press
TI - The Effect of External pH on the Apparent CO2 Affinity of Chlorella saccharophila
JF - Journal of Experimental Botany
DO - 10.1093/jxb/38.7.1203
DA - 1987-07-01
UR - https://www.deepdyve.com/lp/oxford-university-press/the-effect-of-external-ph-on-the-apparent-co2-affinity-of-chlorella-HybqaabJSG
SP - 1203
VL - 38
IS - 7
DP - DeepDyve
ER -