Abstract Detail

Physiological Section

Umebayashi, Toshihiro [1], Fukuda, Kenji [2].

MRI measurements indicate abnormal patterns of water loss in xylem of pine wilt disease infected Pinus thunbergii seedlings.

In pine wilt disease (PWD), embolized tracheids arise as virulent pine wood nematodes (PWNs) migrate through resin canals, leading to host plant death from dehydration. To explain the mechanism of xylem embolisms in PWD, we used a 0.3 Tesla compact MRI to non-destructively monitor the progression of embolisms in Pinus thunbergii seedlings that were either infected with PWNs or subjected to drought. Before this experiment, almost all tracheids were filled with water except for those adjacent to the latewood of the last year. During dehydration of non-infected seedlings, some embolisms first appeared in the earlywood of the last year. The embolized area increased mainly within the same annual ring, and was accompanied by significant loss of water in the inner bark. In the infected seedlings, a mass of embolized tracheids was observed around the inoculation wound. The embolisms spread across the current and the last year annual rings until the xylem was completely embolized. Water loss in the inner bark was limited around inoculation wound until immediately prior to death. Thus, the pattern of embolisms in PWD was markedly different from the pattern induced by water stress. The progress of water loss in PWD may be induced by the decrease of surface tension in the xylem sap.

1 - The University Of Utah, Biology Department, 257S 1400E, Salt Lake City, UT, 84112, USA
2 - The University of Tokyo, Graduate School of Frontier Sciences, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8563, JAPAN

Keywords:
pine wilt disease
embolism
MRI.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PPS001
Abstract ID:276
Candidate for Awards:None