Summary
A fast nuclear-magnetic-resonance imaging method was developed in order to measure simultaneously and quantitatively the water flow velocities in the xylem and the phloem of intact and transpiring plants. Due to technical improvements a temporal resolution of 7 min could be reached and flow measurements could be performed over a time course of 12–30 h. The novel method was applied to the hypocotyl of 35– to 40-day-old, leafy plants ofRicinus communis which were subjected to different light-dark regimes. The results showed that the xylem flow velocities and the xylem volume flow responded immediately to light on-off changes. Upon illumination the flow velocity and the volume flow increased as expected in respect to literature. In contrast, the phloem flow velocity did not change in response to the light-dark regimes. Interestingly, though, the volume flow in the phloem increased during darkness. These findings can be explained by assuming that the conducting area of the phloem becomes enlarged during the dark period due to opening of sieve pores.
Similar content being viewed by others
References
Bourgeois D, Decorps M (1991) Quantitative imaging of slow coherent motion by stimulated echoes with suppression of stationary water signal. J Magn Reson 94: 20–33
Haase A, Frahm J, Matthei D, Merboldt K-D (1986) FLASH imaging: rapid NMR imaging using low flip angle pulses. J Magn Reson 67: 258–266
—, Brandl M, Kuchenbrod E, Link A (1993) Magnetization-prepared NMR microscopy. J Magn Reson Ser A 105: 230–233
Knoblauch M, van Bel AJE (1998) Sieve tubes in action. Plant Cell 10: 35–50
Köckenberger W, Pope JM, Xia Y, Jeffrey KR, Komor E, Callaghan PT (1997) A non-invasive measurement of phloem and xylem water flow in castor bean seedlings by nuclear magnetic resonance microimaging. Planta 201: 53–63
Kuchenbrod E, Landeck M, Thürmer F, Haase A, Zimmermann U (1996) Measurement of water flow in the xylem vessels of intact maize plants using flow-sensitive NMR imaging. Bot Acta 109: 184–186
Lahrech H, Briguet A, Graveron-Demilly D, Hiltbrand E, Moran PR (1987) Modified stimulated echo sequence for elimination of signals from stationary spins in MRI. Magn Reson Med 5: 196–200
Münch E (1930) Die Stoffbewegung in der Pflanze. Fischer, Jena
Peuke AD, Hartung W, Jeschke WD (1994) The uptake and flow of C, N and ions between roots and shoots inRicinus communis L. II: grown with low or high nitrate supply. J Exp Bot 45: 733–740
Rokitta M, Zimmermann U, Haase A (1999) Fast NMR flow measurements in plants using FLASH imaging. J Magn Reson 137: 29–32
Schneider H, Zhu JJ, Zimmermann U (1997) Xylem and cell turgor pressure probe measurements in intact roots of glycophytes: transpiration induces a change in the radial and cellular reflection coefficients. Plant Cell Environ 20: 221–229
Tanner JE (1970) Use of the stimulated echo in NMR diffusion studies. J Chem Phys 52: 2523–2526
Van Bel AJE (1990) Xylem-phloem exchange via the rays: the undervalued route of transport. J Exp Bot 41: 631–644
— (1993) Strategies of phloem loading. Annu Rev Plant Physiol Plant Mol Biol 44: 253–281
Xia Y, Sarafis V, Campbell EO, Callaghan PT (1993) Non-invasive imaging of water flow in plants by NMR microscopy. Protoplasma 173: 170–176
Ziegler H (1977) Flüssigkeitsströme in Pflanzen. In: Hoppe W, Lohmann W, Markl H, Ziegler H (eds) Biophysik. Springer, Berlin Heidelberg New York, pp 561–577
Zimmermann U (1978) Physics of turgor and osmoregulation. Annu Rev Plant Physiol 29: 121–148
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Rokitta, M., Peuke, A.D., Zimmermann, U. et al. Dynamic studies of phloem and xylein flow in fully differentiated plants by fast nuclear-magnetic-resonance microimaging. Protoplasma 209, 126–131 (1999). https://doi.org/10.1007/BF01415708
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01415708