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

Some physiological and growth parameters were studied in cork oak plants inoculated with three pathogenic fungi (Botryosphaeria stevensii, Hypoxylon mediterraneum and Phytophthora cinnamomi) in order to understand the effects of the fungal infection.All inoculated fungi induced the reduction of daily stem growth, stomatal conductance, air-leaf temperature and photochemical 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 shrinkage coinciding with wilting of the plants.The plants inoculated with P. cinnamomi under- went a more gradual decrease in all parameters, whereas H. mediterraneum induced a slight but still significant reduction only in stem growth and shrinkage.Linear variable displacement transducers (LVDT) proved to be a suitable tool to measure some effects of the pathogenesis.(© Inra/Elsevier, Paris.)