Table II. minus2 minus1Photosynthesis, respiration, and photochemical apparatus characteristics of wild type and the tla2 mutant of C. reinhardtii grown photoautotrophically under medium-light (450 μmol photons m−2 s−1) conditions

Photosystem Chl antenna size and reaction center concentrations were measured spectrophotometrically (Melis, 1989). WT, Wild type; n = 3; means ± sd.

Parameter MeasuredWTtla2
Respiration (mmol O2 [mol Chl]−1 s−1)30.2 ± 11.949.1 ± 15.2
Respiration (amol O2 cell−1 s−1)55.8 ± 26.316.2 ± 5.4
Quantum yield, relative units100 ± 25108 ± 17
Photosynthesis (mmol O2 [mol Chl]−1 s−1)106.3 ± 12.8152.3 ± 18.0
Photosynthesis (amol O2 cell−1 s−1)196.2 ± 46.250.3 ± 7.3
Photosynthesis/respiration capacity ratio3.5 ± 1.93.1 ± 1.1
Half-saturation intensity (μmol photons m−2 s−1)210380
Functional PSIIα Chl antenna size249 ± 27160 ± 7
Functional PSIIβ Chl antenna size90 ± 3090 ± 12
Fraction of PSIIα (%)61 ± 146 ± 1
Average PSII Chl antenna size190 ± 20120 ± 9
Functional PSI Chl antenna size180 ± 9123 ± 5