Radiation entropy and its role in the process of photosynthesis

The paper deals with the following problems: 1) radiation entropy and the value of maximum performance coefficient of photosynthesizing systems eta m; 2) problem of physical meaning of eta m and on its association with real processes in photosynthesis. It has been shown that for calculating entropy of nonequilibrium radiation its origin should be known and that the value eta m does not practically limit the processes which proceed in photosynthesis.