SHORT-TERM AND LONG-TERM EFFECTS OF FUSARIUM-OXYSPORUM ELICITORS ON RESPIRATION OF CARNATION CALLUS

The calli of two cultivars of the carnation (Dianthus caryophyllus L.) (with differing degrees of susceptibility to Fusarium oxysgorum f.sp. dianthi in vivo and in vitro) showed a different respiratory pattern when they were treated with Fusarium elicitors (fungal cell-wall components or fungal culture filtrates). The response depended on the time of exposure to the fungus elicitor. Short term (0-180 min) interaction consistently reduced the rate of oxygen uptake of the resistant cultivar; longer exposure (10-20 h) increased the oxygen demand for the same cultivar. Both quantitative (rate of oxygen uptake) and qualitative (activity of the cytochrome and alternative pathway) changes in dark respiration metabolism were observed according to the timing of events in the resistance response.