RAPID SCREENING FOR ALUMINUM TOLERANCE IN CEREALS BY USE OF THE CHLOROPHYLL FLUORESCENCE TEST

The effects of aluminum on the photosynthetic apparatus were examined in cereals grown in nutrient solutions (pH 4.5) at two Al levels (0 an d 148 mu M). The chlorophyll fluorescence kinetics results confirmed t hat the soft wheat 'BHG' cultivar has the potential for growth on acid soils while triticale cultivars 'Niovi' and 'Dada' appeared to be rel atively tolerant. The percentage decrease in F-v/F-m of the less toler ant cultivars after Al-treatment indicated a decrease in the efficienc y of the primary photochemistry of PS II, while the decrease in the ra tio F-v/F-o suggested that exposure of the cultivars 'Dio' and 'Appulo E' to aluminum caused injury to the thylakoid structure. The percenta ge fluctuations of the ratio P-v/P-m were shown to correlate very clos ely with the assessment of injury as evaluated by the relative top fre sh weight. Measurements of chlorophyll fluorescence in vivo could be u sed to monitor injury caused by ''Al-stress'', and thus they may serve as a rapid screening test for Al tolerance.