The Reduction of Protochlorophyllide into Chlorophyllide VI. Calculation of the Size of the Transfer Unit and the Initial Quantum Yield of the Reduction in vivo

A simple and general model of the prolamellar body membrane is applied to kinetic data. The author calculates in this way the size in uiuo of the transfer unit, and the quantum yield in uiuo of the reduction of protochlorophyllide into chlorophyllide. lt is shown that: (1) at ordinary temperature and in the leaf, the transfer unit must comprise about 18 pigment molecules, the size depending on the temperature; (2) at the start of the impact of photons on the leaf, the calculated quantum yield of the reduction is of the order of l, or 2, depending on the value chosen for the molar coefficient of absorption of protochlorophyllide in vivo.