On the proper use of sigma analysis in the study of flash-induced oxygen evolution.

Analysis of oxygen yield by photosynthetic higher plants systems submitted to flash sequence using the so-called sigma method as proposed in Lavorel (1976), J Theor Biol 57: 171-185 has been recently criticized in this Journal by Meunier and Popovic (1989), Photosynth Res 22: 131-136. By properly applying the above method-in particular using Meunier and Popovic's own data-it is argued that the criticism is not justified.