title: Visualization of water transport into soybean nodules by Tof-SIMS cryo system.
abstract: This paper examined the route of water supply into soybean nodules through the new visualization technique of time of flight secondary ion mass spectrometry (Tof-SIMS) cryo system, and obtained circumstantial evidence for the water inflow route. The maximum resolution of the Tof-SIMS imaging used by this study was 1.8 μm (defined as the three pixel step length), which allowed us to detect water movement at the cellular level. Deuterium-labeled water was supplied to soybean plants for 4h and the presence of deuterium in soybean nodules was analyzed by the Tof-SIMS cryo system. Deuterium ions were found only in the endodermis tissue surrounding the central cylinder in soybean nodules. Neither xylem vessels nor phloem complex itself did not indicate any deuterium accumulation. Deuterium-ion counts in the endodermis tissue were not changed by girdling treatment, which restricted water movement through the phloem complex. The results strongly indicated that nodule tissues did not receive water directly from the phloem complex, but received water through root cortex apoplastic pathway from the root axis.
authors.affiliation: School of Agriculture, Kinki University, Nara 631-8505, Japan. Electronic address: iijimamorio@nara.kindai.ac.jp.
authors.forename: Morio
authors.initials: M
authors.lastname: Iijima
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Toshimasa
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki 036-8561, Aomori, Japan.
authors.forename: Michio
authors.initials: M
authors.lastname: Kawasaki
authors.affiliation: Technical Center of Nagoya University, Nagoya 464-8601, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kato
authors.affiliation: School of Agriculture, Kinki University, Nara 631-8505, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Yamane
mesh_terms: D001692:Biological Transport; D003903:Deuterium / Q000378:metabolism; D052585:Phloem / Q000378:metabolism; D053204:Root Nodules, Plant / Q000378:metabolism; D013025:Glycine max / Q000378:metabolism*; D018629:Spectrometry, Mass, Secondary Ion; D014867:Water / Q000378:metabolism*; D052584:Xylem / Q000378:metabolism
chemical_list: D014867:Water; D003903:Deuterium
keywords: Apoplastic pathway; Nodule; Soybean; Time of flight secondary ion mass spectrometry; Water source