Chlorophyll fluorescence as a tool to identify drought stress in Acer genotypes

The effect of drought stress on continuous excitation chlorophyll fluorescence parameters and the OJIP transient is examined in cultivars of Acer campestre, A. platanoides and A. pseudoplatanus. Comparisons between whole tree level drought and desiccation of detached leaves under laboratory conditions is evaluated using both fluorescence parameters and differential kinetics. Data presented in this study suggests similarities exist between drought and desiccation. Chlorophyll fluorescence parameters which are both suitable and unsuitable at identifying drought stress are discussed and evaluated. New or uncommon fluorescence parameters and methods of analysis which may prove beneficial as drought detection tools are assessed. The over utilisation of the parameter Fv/Fm is also discussed. Results suggest utilisation of the parameters PIABS, Fo/Fm and V0(Bo) is recommended in preference to Fv/Fm, in studies aiming to identify drought stress in trees.