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Magnetoreception in Plants

Diamagnetic anisotropy is the physical property of the membranes molecular structure that has the

potential to be infuenced by MFs. Many inorganic and virtually all organic compounds have some

degree of diamagnetism. Te relationship between the induced magnetic moment and the applied feld

characterizes the magnetic properties of a substance and is referred to as magnetic susceptibility, χm

M

˜m = H

where M is magnetization or magnetic moment per unit volume, and H is feld strength. χm is dimen­

sionless but with a negative sign for diamagnetic substances. Te energetics for orientation in an MF

are favorable for structures made up of a large number of parallel molecules and explains the efects of

these felds on retinal rods, chloroplasts, lecithin vesicles, and synthetic phospholipid bilayers. Most

of the diamagnetic anisotropy of lipids is contributed by their acyl chains and biological membranes,

with their highly ordered phospholipid bilayer structure, would be expected to exhibit substantial dia­

magnetic properties (Rosen, 2003). Te increased permeability of a phospholipid bilayer to low-molec­

ular-weight solutes, during SMF exposure occurs with SMFs >10 mT and was evident within 1 min of

exposure onset. Tis phenomenon has been attributed to deformational changes within the membrane

because of its diamagnetic properties. In the presence of a moderate SMF, the enhanced diamagnetic

anisotropy of biological membranes is sufcient to result in a slow reorientation of their phospholipid

molecules (Rosen, 2003).

When a magnetic feld is present in cell systems, three types of magnetic forces can act on subcellular

components and ions:

1. the Lorentz force,

F = vB q

L [

]

where B is the magnetic induction, q is the ion electric charge, and v is its velocity

2. the magnetic gradient force (Zablotskii et al., 2014)

F°B ˜°B²

where ∇ is the diferential operator nabla

3. the concentration-gradient magnetic force (Svendsen and Waskaas, 2020)

F°n ˜

°

B² n

(where ∇n is the gradient of the concentration of the diamagnetic and paramagnetic species). Tere are

hundreds of diamagnetic and paramagnetic species inside living cells, many of which may have very

large concentration gradients (Sear, 2019) and the presence of a high MF (HMF), and a relatively large

concentration gradient magnetic force is operative.

Cell behavior depends on the membrane potential and bioelectric signals control. For example,

undiferentiated cells have low membrane potential that allows them to be depolarized and highly plas­

tic. In contrast, cells that are mature, terminally diferentiated, and quiescent tend to be hyperpolarized.

Terefore, by changing the membrane voltage, one can also control cell rigidity and functions. Driving

the cell membrane potential with an MF could represent a new tool for cell modulation. Unlike the

electric feld, the MF is not attenuated by living tissue and penetrates through the whole body. By con­

sidering the Nernst potential, the free-energy change for the difusion of an electrolyte into the cell is

˛ ni ˆ

G

RT ln

+ zFV

˜

=

˙

˘

m

˝ no ˇ