Effect of Triacontanol on Chlamydomonas

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Abstract
Increased photosynthetic CO2 assimilation by Chlamydomonas reinhardtii cells treated with triacontanol (TRIA) was not due to changes in glycolate excretion, CO2 compensation point, or the sensitivity of photosynthetic CO2 assimilation to O2. Kinetic analysis of TRIA-treated cells showed that the increase in photosynthetic CO2 assimilation was a result of an increase in the apparent Vmax for intact cells. The total activity of ribulose-P2 carboxylase/oxygenase was higher in cell lysates from TRIA-treated cells. However quantification of this enzyme concentration by binding of [14C]carboxyarabinitol-P2 did not show an increase in TRIA-treated cells. Thus, there was an increase in the specific activity of ribulose-P2 carboxylase/oxygenase extracted from Chlamydomonas cells treated with TRIA. TRIA alone had no effect on the activity of the enzyme in cell lysates from Chlamydomonas or purified from spinach (Spinacia oleracea L.) leaves.