Effects of pine wood nematode,Bursaphelenchus xylophilus,on some physio-biochemical indexes of Japanese black pine,Pinus thunbergii

Pine wilt caused by pine wood nematode,Bursaphelenchus xylophilus,is a serious disease for pines.In this paper,changes of some physio-biochemical indexes in stem of 3-4 years old Japanese black pine,Pinus thunbergii inoculated with B.xylophilus were studied.The results showed that after nematode invasion,the soluble carbohydrate in pine seedlings decreased,and it was more significant at the middle and late stages of disease development.The soluble protein and ascorbic acid in pine seedlings decreased gradually,and the free amino acid in pine seedlings also decreased.It was suggested that the content of soluble protein in stems of pine could be used for early diagnosis of the disease.Roles of the four physio-biochemical indexes in pathogenic mechanism of the disease were discussed.