Effects of three fungal pathogens on water relations, chlorophyll fluorescence and growth of Quercus suber L.

Some physicological and growth parameters were studied in cork oak plants i noculated with three pathogenic fungi (Botryosphaeria stevensii, Hypoxylon mediterraneum and Phytophthora cinnamomi) in order to understand the effect s of the fungal infection. All inoculated fungi induced the reduction of da ily stem growth, stomatal conductance, air-leaf temperature and photochemic al efficiency. The more aggressive pathogens, B. stevensii and P. cinnamomi , induced the sharpest decline in all growth and physiological parameters. A sudden decline of all variables was caused by B. stevensii within 6 days after inoculation, followed by a temporary increase in maximum daily shrink age coinciding with witting of the plants. The plants inoculated with P. ci nnamomi underwent a more gradual decrease in all parameters, whereas H. med iterraneum induced a slight but stilt significant reduction only in stem gr owth and shrinkage. Linear variable displacement transducers (LVDT) proved to be a suitable tool to measure some effects of the pathogenesis. ((C) Inr a/Elsevier, Paris).