Abstract
Responses of different resistant families of Pinus thunbergii and P. densiflora to the pine wood nematode (Bursaphelenchus xylophilus) were investigated from the view points of xylem water conductance and histological features. Survived pine seedlings after inoculation with pine wood nematodes reacted to the nematode invasion independent of the strength of resistant families as follow: partial loss of xylem water conductance caused by embolism, destruction and degeneration of parenchyma cells in dysfunctional xylem area, and normal parenchyma cells and cambium in functional xylem area. These reactions are the expression of resistance of P. thunbergii and P. densiflora to pine wood nematode invasion.
