Nuclear-magnetic-resonance imaging of leaves ofMesembryanthemum crystallinum L. plants grown at high salinity |
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Authors: | L Walter A Balling U Zimmermann A Haase W Kuhn |
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Institution: | (1) Lehrstuhl für Biotechnologie der Julius-Maximilians-Universität Würzburg, Röntgenring 11, D-8700 Würzburg, Federal Republic of Germany;(2) Max-Planck-Institut für Biophysikalische Chemie, Am Fassberg, D-3400 Göttingen, Federal Republic of Germany;(3) Bruker Analytische Messtechnik GmbH, Am Silberstreifen, D-7512 Rheinstetten, Federal Republic of Germany |
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Abstract: | Differences in water binding were measured in the leaf cells ofMesembryanthemum crystallinum L. plants grown under high-salinity conditions by using nuclear-magnetic-resonance (NMR) imaging. The 7-Tesla proton NMR imaging system yielded a spatial resolution of 20·20·100 m3. Images recorded with different spin-echo times (4.4 ms to 18 ms) showed that the water concentrations in the bladder cells (located on the upper and lower leaf surface), in the mesophyll cells and in the water-conducting vessels were nearly identical. All of the water in the bladder cells and in the water-conducting vessels was found to be mobile, whilst part of the water in the mesophyll cells was bound. Patches of mesophyll cells could be identified which bound water more strongly than the surrounding mesophyll cells. Optical investigations of leaf cross-sections revealed two types of mesophyll cells of different sizes and chloroplast contents. It is therefore likely that in the small-sized mesophyll cells water is strongly bound. A long-term asymmetric water exchange between the mesophyll cells and the bladder cells during Crassulacean acid metabolism has been described in the literature. The high density of these mesophyll cells in the lower epidermis is a possible cause of this asymmetry.Abbreviations CAM
Crassulacean acid metabolism
- NMR
nuclear magnetic resonance
- TE
spin-echo time |
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Keywords: | Crassulacean acid metabolism Leaf (water binding) Mesembryanthemum Mesophyll (water binding) Nuclear magnetic resonance microscopy Water free and bound |
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