Three types of the concentration dependence of the red and far-red chlorophyll a fluorescence ratio

In the paper the dependence of the F-682/F-734 on the concentration in plants, grown under continuous light and natural photoperiod is studied. For natural photoperiod the duration of light for all probes was the same, as since leaves with different colors are selected at a time. It is shown, the dependence of the F-682/F-734 ratio on chlorophyll concentration in plant, grown under high-intensity continuous is described by a parabolic function and under intermittent light - exponential function. Third type of concentration dependence of the parameter F-682/F-734 was obtained in leaves of poplar in the process of vegetation under study of fluorescence and pigment characteristics. The dependence has complicated character and known functions cannot describe it. It is concluded, that all known dependences of the F-682/F-734 ratio on concentration of chlorophyll to this moment are used to concrete conditions of growth of plants and the method of probes choice for measurement. Now the universe function, connecting the relation between red and far-red fluorescence with chlorophyll content, is not existed.