title: Direct observation of local xylem embolisms induced by soil drying in intact Zea mays leaves.
abstract: The vulnerability of vascular plants to xylem embolism is closely related to their stable long-distance water transport, growth, and survival. Direct measurements of xylem embolism are required to understand what causes embolism and what strategies plants employ against it. In this study, synchrotron X-ray microscopy was used to non-destructively investigate both the anatomical structures of xylem vessels and embolism occurrence in the leaves of intact Zea mays (maize) plants. Xylem embolism was induced by water stress at various soil drying periods and soil water contents. X-ray images of dehydrated maize leaves showed that the ratio of gas-filled vessels to all xylem vessels increased with decreased soil water content and reached approximately 30% under severe water stress. Embolism occurred in some but not all vessels. Embolism in maize leaves was not strongly correlated with xylem diameter but was more likely to occur in the peripheral veins. The rate of embolism formation in metaxylem vessels was higher than in protoxylem vessels. This work has demonstrated that xylem embolism remains low in maize leaves under water stress and that there xylem has characteristic spatial traits of vulnerability to embolism.
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea.
authors.forename: Jeongeun
authors.initials: J
authors.lastname: Ryu
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea.
authors.forename: Bae Geun
authors.initials: BG
authors.lastname: Hwang
authors.affiliation: Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea.
authors.forename: Yangmin X
authors.initials: YX
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea Center for Biofluid and Biomimic Research, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, 790-784, Republic of Korea sjlee@postech.ac.kr.
authors.forename: Sang Joon
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D003681:Dehydration / Q000503:physiopathology; D018515:Plant Leaves / Q000502:physiology*; D011859:Radiography; D012987:Soil; D052584:Xylem / Q000502:physiology*; D003313:Zea mays / Q000502:physiology*
chemical_list: D012987:Soil
keywords: Drought stress; X-ray imaging; Zea mays (maize).; embolism; soil drying; xylem