Use of a Glass Electrode for Measuring Rapid Changes in Photosynthetic Rates

Abstract

1. A continuously recording glass electrode apparatus has been described for measuring carbon dioxide concentration changes in solution. The limits of applicability of the apparatus have been analyzed. 2. The glass electrode apparatus has been used for the measurement of transient rates of photosynthesis by algal suspensions. 3. The decline of the photosynthetic rate in high light at carbon dioxide partial pressures less than 0.5 per cent atmosphere, observed in the glass electrode apparatus, has been confirmed by steady state experiments in which flowing gas streams were analyzed.

Reversible pH Changes in Cells of Chlamydomonas reinhardi Resulting from CO2 Fixation in the Light and Its Evolution in the Dark

“…The pH change exhibited by intact cells of C. reinhardi described here and observed previously by Shuldiner and Ohad (32) is of a different nature; it is a manifestation of CO2 uptake in the light and CO. release in the dark. Such pH changes resulting from changes in CO2 concentration have been observed and studied previously (9,29). Since photosynthetic oxygen evolution is linked to NADP reduction, continuous oxidation of water will depend on the reoxidation of NADPH that takes place during the operation of the Calvin cycle.…”

“…Most of the observations of Shuldiner and Ohad (32) (34) or by recording the pH change (9,29). In addition, with intact cells, after turning off the light the pH decrease begins after a lag of about 30 sec.…”

The effect of carbon on algal growth—Its relationship to eutrophication

“…Steemann Nielsen (l955a) in referring to the high CO 2 concentrations (0.2 -1.0 percent) required by Osterlind (1951 a) and by Rosenberg (1954) to achieve maximum photosynthetic rates with Scenedesmus and Chlorella claimed that in both cases a dense algal concentration caused enough competition for the available carbon so that maximum photosynthetic rates could be measured only at these high CO 2 concentrations. Thus, the cultures were actually carbon limited at the low CO 2 concentrations and no true measurements of maximum photosynthetic rates were possible.…”

Carbon Dioxide as Carbon Source and Narcotic in Photosynthesis and Growth of Chlorella Pyrenoidosa

“…and tbe 4tli articles the experiments were made without presence of IlCOa" ions. Tbe results of the experiments on pbotosynthesis made by Osterlind 1951 and by Rosenberg 1954 do not apparently support this viewpoint. They will be discussed in sections 4 and 5.…”

“…For convenience sake tbe equilibrium values fnr , ' given in Table 1 d pll by Rosenberg 1954 were used for computing the changes in pH. The concentrations of free CO2 used in each single determination is the intermediate between the concentration at the start and at the end.…”