caa a22 4500 397520441 CHVBK 20180308164631.0 cr unu---uuuuu 161202e199504 xx s 000 0 eng 10.1093/jxb/46.4.441 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.4.441 Water relations, xylem embolism and histological features of Pinus thunbergii inoculated with virulent or avirulent pine wood nematode, Bursaphelenchus xylophilus [Elektronische Daten] [Takefumi Ikeda, Tomoya Kiyohara] The development process of pine wilt disease caused by Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle, pine wood nematode, was studied ecophysiologically and histologically in relation to pathogenicity of B. xylophilus. Judging from the predawn xylem pressure potential of needles, the heat pulse velocity, and the soil water potential, the control Pinus thunbergii Parl., used for the study, was not water-stressed. Virulent B. xylophilus isolate can kill non-waterstressed pines. In virulent B. xylophilus isolateinoculated pines, the predawn xylem pressure potential of needles abruptly decreased when the colour of 1-year-old needles changed to brown and then the water conducting function of the xylem was lost completely. Avirulent B. xylophilus isolate does not affect the needle colour and the xylem pressure potential of pines. Avirulent B. xylophilus isolate-inoculated pines, however, responded to nematode invasion by decreasing hydraulic conductance of stem and root xylems. In addition, oleoresin exudation slightly decreased. The decreased hydraulic conductance results from embolism of tracheids caused by cavitation in the central part of the xylem. From histological observation, all of the parenchyma cells in virulent B. xylophilus isolateinoculated pines died. In contrast, the parenchyma cells, degenerated in avirulent B. xylophilus isolateinoculated pines, were limited in the embolized region of the xylem. The difference between the response of pine to the virulent B. xylophilus isolate invasion and that to avirulent B. xylophilus isolate invasion indicates that nematode-induced death of pine relates to the death of parenchyma cells, as well as the decrease in xylem hydraulic conductance. © Oxford University Press Articles nationallicence Embolism nationallicence hydraulic conductance nationallicence parenchyma cells nationallicence pathogenicity of pine wood nematode nationallicence pine wilt disease nationallicence Ikeda Takefumi Kyushu Research Center, Forestry and Forest Products Research Institute, Ministry of Agriculture, Forestry and Fisheries, Kurokami, Kumamoto, 860 Japan aut Kiyohara Tomoya Kyushu Research Center, Forestry and Forest Products Research Institute, Ministry of Agriculture, Forestry and Fisheries, Kurokami, Kumamoto, 860 Japan aut Journal of Experimental Botany Oxford University Press 46/4(1995-04), 441-449 0022-0957 46:4<441 1995 46 exbotj https://doi.org/10.1093/jxb/46.4.441 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.4.441 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ikeda Takefumi Kyushu Research Center, Forestry and Forest Products Research Institute, Ministry of Agriculture, Forestry and Fisheries, Kurokami, Kumamoto, 860 Japan aut NATIONALLICENCE 700 1- Kiyohara Tomoya Kyushu Research Center, Forestry and Forest Products Research Institute, Ministry of Agriculture, Forestry and Fisheries, Kurokami, Kumamoto, 860 Japan aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/4(1995-04), 441-449 0022-0957 46:4<441 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford