The quantum requirement of photosynthesis in Chlorella

Spectral light absorption and quantum yield of photosynthesis in sea ice microalgae and a bloom of Phaeocystis pouchetii from McMurdo Sound, Antarctica

“…The quantum yield of photosynthesis (Q), defined as gross production (measured either as moles of CO-, fixed or O2 produced) per mole of absorbed light, has been evaluated for laboratory cultures of microalgae (Manning et al 1938, Emerson & Lewis 1943, Govindjee et al 1968, Ng & Bassham 1968, Welschmeyer & Lorenzen 1981; for phytoplankton from a variety of water types (Tyler 1975, Dubinsky & Berman 1976, Morel 1978, Tilzer 1983, 1984, Meffert & Overbeck 1985, Kishino et al 1986); for Antarctic phytoplankton (Tilzer et al 1985(Tilzer et al , 1986; and for benthic marine macroalgae (Dring & Luning 1985, Luning & Dring 1985. To date, no measurements of cP for sea ice microalgae or the cosmopolitan prymnesiophyte Phaeocystis pouchetii have been reported in the literature.…”

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“…As the illumination approached the compensation point the respiration correction became large and the corrected quantum demand fell to 4 hv/O^. Some 13 years later Ng & Bassham (1968) disassociated themselves from this value for the quantum demand reported by Bassham et al (1955) and, by repetition of the experiment, claimed that the minimum value was XO-bhv/O^, rather than 7 4 as reported by Bassham et al (1955). Ng & Bassham appeared anxious to align the quantum demand with the Z-scheme but it is difficult to have any confidence in either result since they suggested the discrepancy was caused by underestimation of the incident irradiance in the earlier experiments.…”

Photosynthesis and biosynthetic pathways to chemicals

“…This would appear to be the maximum possible efficiency of the photosynthetic reaction. Probably the actual efficiency is somewhat less, but measurements of quantum requirements in the range of 8 to 10 einsteins required per O 2 molecule evolved has been reported (5).…”

“…A higher intensity of photosynthesis could be obtained in arid regions, however, if ample water and year around growing temperatures could be provided, and-other physiological factors could be optimized. 5 Calculated maximum biomass ~roduction and reported hiSh ~ields A typical solar irradiance 1n arid 2 regions at 35° lat1tu e is the value in the U.S. southwest of 4,610 Kcal/m day averaged year round for 24 hrs per day. From the foregoing discussion, the upper limit for biomass production can be calculated by multiplying the effic~ency, 0.066 times the daily total energy times 0.237.…”

“…This would be an extremely important advantage in some areas of the world. 5. Carbon dioxide could be obtained from flue gasses from fossil fuel power plants, thus decreasing the amount of CO?…”