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Magnetoreception in Plants

 

FIGURE 5.14 Relative changes of the membrane potential [(Vm(B) − Vm(0))/Vm(0)] ×100%, versus B for individual

contributions of K⁺, Na⁺, Ca²⁺, and Cl⁻ ions as calculated from the last equation. (Adapted from Zablotskii et al.

(2021).)

Te possibility that strong, SMFs might have an infuence on biological processes has been discussed,

and reports implicate high MFs in alterations of the cleavage plane during cell division (Denegre et al.,

1998) and other cellular disorders (Valiron et al., 2005). Nevertheless, the common viewpoint is that

presently achievable SMFs do not have a lasting efect on biological systems (Paul et al., 2006). In

Arabidopsis, high MFs may compromise some aspects of the transcriptional machinery, and efectively

arrest the process. Tis feld dependence may suggest that magnetic orientation or magnetophoresis

plays a role in the seemingly dual nature of the response. Te biomacromolecules involved in signal

transduction and gene regulation may experience forces and/or torques that are induced by the presence

of the MF. In addition, the macromolecules may experience magnetophoresis due to forces generated by

inhomogeneities in the applied MF.

According to Paul et al. (2006), MFE is sufcient to perturb the delicate conformational dynamics

involved in aspects of gene regulation, thereby resulting in the diferential expression of a variety of

genes in the plant. Te magnetic orientation efects are estimated to be 10–100 times larger than the

magnetophoretic forces, and thus it is likely that magnetophoresis plays a minor role in the induction

or repression of gene expression. Nominally 15 T is the threshold of feld strength required to initiate

such stress response, indicating that macromolecular orientation plays a role in feld strengths >15 T.

Terefore, exposure to MFs above 15 T induces the perturbation of metabolic processes in the presence

of strong MFs and may be useful for guiding future research designed to calibrate safe exposure stan­

dards for living organisms (Paul et al., 2006).

Another interesting aspect is that nonuniform MFs may exert a ponderomotive force on amyloplasts

which can result in intracellular magnetophoresis. Tus, plants can perceive an MF of sufcient inten­

sity and gradient and respond to the resulting amyloplast displacement as they do to gravity. In fact,

by using high gradient MFs it is possible to induce curvature in roots, an efect defned magnetotro­

pism, although it seems that the cause of the growth response is a ponderomotive force and not the

MF (Penuelas et al., 2004). Magnetic gradients are therefore an important tool to study localized mass

interactions independent of gravity efects on the entire organism. Te forces generated by a magnetic

system are sufcient to provide a directional stimulus (i.e., induce curvature) even under weightlessness

conditions and that depends on the distance, the magnetic gradient afects starch particles similar to

gravity (Hasenstein et al., 2013).