foods with a commercial interest and presents the effect on the production of natural
bioactive compounds.
5.2.1.2 Electric and Magnetic Fields
Magnetic fields (MFs) are considered an abiotic factor that can induce eustress with
significant effects on the growth and development of plants. The effect of light,
gravity, mechanical damage, and electrical signaling on plants has been studied and
documented over the past years concluding strong facts relating to phototropism,
gravitropism, and thigmotropism (Maffei 2014). The geomagnetic field (GMF) is a
natural component of our environment, however, its impact on plant growth and
development is not well-understood, moreover, the effects of artificial magnetic
fields on plants have been poorly studied (Maffei 2014). Several experiments with
lower and higher values than the GMF has been conducted with predominantly
positive effects depending on the plant, time of exposure and intensity. For
example, an increase in germination or subsequent seedling growth barley, corn,
beans, wheat, hornwort, mung bean, pea, chickpea, tomato, and okra, but it was
reduced in seeds of rice. In a similar way, the effect on roots, shoots, gravitropism,
photosynthesis, and lipid composition present a similar pattern (Maffei 2014).
Several theories and studies about the biological effect on MF have been proposed. A polar structure in various chemical bonds in the organic material may be
linked to the polar water molecules and dissociated ions of mineral salts conferring
magnetic properties (Chepets et al. 1985). A MF can decrease the disease index of
plants due to the modulation of calcium signaling, and proline and polyamines
pathways (Radhakrishnan 2019). The plant cells contain about 4500 iron atoms in
the ferritin molecules involved in growth and metabolism. The magnetic rotator
moment of ultimate iron atoms creates an external MF which collectively generates
an atom re-positioning in the direction of MF that leads to an increase of the plant
temperature (Vaezzadeh et al. 2006). Photoreceptors have been also proposed to be
potential magnetoreceptors since cryptochromes and phytochromes produce radical
pairs after the exposure to their corresponding light wavelength triggers (Maffei
2014; Dhiman and Galland 2018). Cryptochrome-dependent responses such as
blue-light-dependent anthocyanin accumulation and blue-light-dependent degradation of CRY2 protein were enhanced at higher magnetic intensities in
Arabidopsis mutants lacking cryptochromes (Ahmad and Jones 1979). Limited
information is available on the molecular basis and the function of the MF receptors
and their activation by physiological signals, therefore, their involvement in
directing the overall response in different plant organs is yet to be determined
(Radhakrishnan 2019).
Static magnetic field (SMF) exposition in plants has been found to be an
effective and emerging tool to control diseases and increase tolerance against the
adverse environment (Radhakrishnan 2019). However, a small number of studies
have been attempted to determine the role of MF on plant tolerance against various
156
H. Aguirre-Becerra et al.
bioactive compounds.
5.2.1.2 Electric and Magnetic Fields
Magnetic fields (MFs) are considered an abiotic factor that can induce eustress with
significant effects on the growth and development of plants. The effect of light,
gravity, mechanical damage, and electrical signaling on plants has been studied and
documented over the past years concluding strong facts relating to phototropism,
gravitropism, and thigmotropism (Maffei 2014). The geomagnetic field (GMF) is a
natural component of our environment, however, its impact on plant growth and
development is not well-understood, moreover, the effects of artificial magnetic
fields on plants have been poorly studied (Maffei 2014). Several experiments with
lower and higher values than the GMF has been conducted with predominantly
positive effects depending on the plant, time of exposure and intensity. For
example, an increase in germination or subsequent seedling growth barley, corn,
beans, wheat, hornwort, mung bean, pea, chickpea, tomato, and okra, but it was
reduced in seeds of rice. In a similar way, the effect on roots, shoots, gravitropism,
photosynthesis, and lipid composition present a similar pattern (Maffei 2014).
Several theories and studies about the biological effect on MF have been proposed. A polar structure in various chemical bonds in the organic material may be
linked to the polar water molecules and dissociated ions of mineral salts conferring
magnetic properties (Chepets et al. 1985). A MF can decrease the disease index of
plants due to the modulation of calcium signaling, and proline and polyamines
pathways (Radhakrishnan 2019). The plant cells contain about 4500 iron atoms in
the ferritin molecules involved in growth and metabolism. The magnetic rotator
moment of ultimate iron atoms creates an external MF which collectively generates
an atom re-positioning in the direction of MF that leads to an increase of the plant
temperature (Vaezzadeh et al. 2006). Photoreceptors have been also proposed to be
potential magnetoreceptors since cryptochromes and phytochromes produce radical
pairs after the exposure to their corresponding light wavelength triggers (Maffei
2014; Dhiman and Galland 2018). Cryptochrome-dependent responses such as
blue-light-dependent anthocyanin accumulation and blue-light-dependent degradation of CRY2 protein were enhanced at higher magnetic intensities in
Arabidopsis mutants lacking cryptochromes (Ahmad and Jones 1979). Limited
information is available on the molecular basis and the function of the MF receptors
and their activation by physiological signals, therefore, their involvement in
directing the overall response in different plant organs is yet to be determined
(Radhakrishnan 2019).
Static magnetic field (SMF) exposition in plants has been found to be an
effective and emerging tool to control diseases and increase tolerance against the
adverse environment (Radhakrishnan 2019). However, a small number of studies
have been attempted to determine the role of MF on plant tolerance against various
156
H. Aguirre-Becerra et al.