Research Branch Report No. 231

Leaf temperatures of Eucalyptus sieberi seedlings infected by Phytophthora cinnamomi under growth-room conditions.  J. D. Morris and G. C. Marks.  October 1983.  5 pp. (unpubl.)

SUMMARY

Leaf temperatures of healthy and Phytophthora cinnamomi Rands (root rot) -infected Eucalyptus sieberi L.A.S. Johnson (silvertop) seedlings were continuously monitored over a three-day period, during which three intensities of artificial illumination were applied.

The leaves of infected seedlings remained above air temperature throughout each day, whereas healthy seedlings usually maintained their leaves below air temperature. The differences in temperature between infected and healthy seedlings varied from approximately 2°C at the lowest level of radiation to approximately 5°C at the highest level. This temperature differential probably reflects a reduction in transpiration of P. cinnamomi-infected eucalypts, and suggests that high temperature injury may be a factor in dieback resulting from P. cinnamomi attack.