Abstract
High-gradient magnetic fields (HGMFs) were used to induce intracellular magnetophoresis of amyloplasts. The HGMFs were generated by placing a small ferromagnetic wedge into a uniform magnetic field or at the gap edge between two permanent magnets. In the vicinity of the tip of the wedge the dynamic factor of the magnetic field, ▽(H2/2), was about 109 Oe2 · cm−1, which subjected the amyloplasts to a force comparable to that of gravity. When roots of 2-d-old seedlings of flax (Linum usitatissimum L.) were positioned vertically and exposed to an HGMF, curvature away from the wedge was transient and lasted approximately 1 h. Average curvature obtained after placing magnets, wedge and seedlings on a 1-rpm clinostat for 2 h was 33 ± 5 degrees. Roots of horizontally placed control seedlings without rotation curved about 47 ± 4 degrees. The time course of curvature and changes in growth rate were similar for gravicurvature and for root curvature induced by HGMFs. Microscopy showed displacement of amyloplasts in vitro and in vivo. Studies with Arabidopsis thaliana (L.) Heynh. showed that the wild type responded to HGMFs but the starchless mutant TC7 did not. The data indicate that a magnetic force can be used to study the gravisensing and response system of roots.
Similar content being viewed by others
Abbreviations
- HGMF:
-
high-gradient magnetic field
- emu:
-
electromagnetic units
- Oe:
-
Oersted
References
Audus LJ (1960) Magnetotropism: a new plant growth response. Nature 185: 132–134
Audus LJ, Whish JC (1964) Magnetotropism. In: Barnothy MF (ed) Biological effects of magnetic fields, vol 1. Plenum Press, New York, pp 170–182
Bates LF (1939) Modern magnetism. Cambridge University Press, London
Brown AH, Chapman DK, Lewis RF, Venditti AL (1990) Circumnutations of sunflower hypocotyls in satellite orbit. Plant Physiol 94: 233–238
Caspar T, Huber SC, Sommerville CR (1986) Alterations in growth photosynthesis and respiration in a starchless mutant of Arabidopsis thaliana (L.) Heynh deficient in chloroplast phosphoglucomutase activity. Plant Physiol 79: 1–7
Caspar T, Pickard BG (1989) Gravitropism in a starchless mutant of Arabidopsis. Implications for the starch-statolith theory of gravisensing. Planta 177: 185–197
Hasenstein KH (1991) Measurement of circumnutation in maize roots. Microgravity Sci Tech 4: 262–266
Iversen TH (1969) Elimination of geotropic responsiveness in roots of cress (Lepidium sativum) by removal of statolith starch. Physiol Plant 22: 1251–1262
Kiss JZ, Hertel R, Sack FD (1989) Amyloplasts are necessary for full gravitropic sensitivity in roots of Arabidopsis thaliana. Planta 177: 198–206
Kreidl A (1893) Weitere Beiträge zur Physiology des Ohrlabyrinthes. II. Versuche an Krebsen. Sitzungsber Akad Wiss Wien 102: 149–174
Kuznetsov AA, Kuznetsov OA (1989) Simulation of gravity force for plants by high gradient magnetic field. Biofizika 35: 835–840
Piruzyan LA, Kuznetsov AA, Chikov VM (1980) About the magnetic heterogeneity of biological systems. Izvestiya Acad Sci USSR Ser Biol 5: 645–653
Poff KL, Martin H (1989) Site of graviperception in roots: a reexamination. Physiol Plant 76: 451–455
Schwarzacher JC, Audus LJ (1973) Further studies in magnetotropism. J Exp Bot 24: 459–474
Senftle FE, Hambright WP (1969) Magnetic susceptibility of biological materials. In: Barnothy MF (ed) Biological effects of magnetic fields, vol 2. Plenum Press, New York, pp 261–306
Spurr AR (1969) A low-viscosity embedding medium for electron microscope. J Ultrastruct Res 26: 31–34
Staves MP, Wayne R, Leopold AC (1992) Hydrostatic pressure mimics gravitational pressure in characean cells. Protoplasma 168: 141–152
Theil EC (1987) Ferritin: structure, gene regulation, and cellular function in animals, plants, and microorganisms. Annu Rev Biochem 56: 289–315
Weast RC (1987) Handbook of chemistry and physics, 68th edn
Weisenseel MH, Becker HF, Ehlgötz JG (1992) Growth, gravitropism and endogenous ion currents of cress roots (Lepidium sativum L). Plant Physiol 100: 16–25
Author information
Authors and Affiliations
Corresponding author
Additional information
We thank Dr. John Kiss, Miami University, Ohio for providing the Arabidopsis seeds. This work was supported by NASA grant NAGW-3656
Rights and permissions
About this article
Cite this article
Kuznetsov, O.A., Hasenstein, K.H. Intracellular magnetophoresis of amyloplasts and induction of root curvature. Planta 198, 87–94 (1996). https://doi.org/10.1007/BF00197590
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00197590