In Vivo Chlorophyll Fluorescence as a Tool for Stress Detection in Plants

Abstract

A definition of stress to plants and a general stress concept are presented including a list of possible major natural and anthropogenic stress factors. It is shown that the white light or laser-induced chlorophyll fluorescence of predarkened leaves is a very suitable tool for early stress detection in plants as well as for regeneration studies. The different chlorophyll fluorescence parameters to be measured are: variable fluorescence (ratio fmax/fo), the vitality index (fluorescence decrease ratio, Rfd-values), the stress adaption index Ap, the fluorescence spectra (ratio F690/F735) and the photochemical Q- and non-photochemical E-quenching (qQ and qE). Some examples of the measurement of these parameters under stress conditions are given.