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Magneto-Priming: A Novel Technique Towards Improved Seed Germinability

abiotic stresses (Kataria & Jain, 2019). Further, the exposure of seeds to

SMF of 200 mT for 1-hour has been reported to induce various positive

responses such as the increasing activities of α-amylase and protease, nitrate

reductase, nitric oxide contents along with a reduction in hydrogen peroxide

(H2O2), superoxide (O2

•–) and malondialdehyde (MDA) contents in leaves

of soybean under UV-stress (Kataria et al., 2020). Moreover, magnetic field

exposure on soybean has been reported to enhance the sugar and protein

contents that would act as osmoprotectants in salt-affected callus and

thereby minimize the adversities of salt stress (Radhakrishnan et al., 2012).

Magneto-priming also reduces the impact of salt and drought stress in plants

by enhancing the water uptake through root cells (Alvarez et al., 2020, 2021;

Conrath, 2009; Kaya et al., 2006; Sarraf et al., 2020). It has been reported

that an increase in Ca²⁺ ion would play a vital role in the drought tolerance

mechanism under magnetic field exposure since the impairment between the

cell’s plasma membrane and photosynthetic apparatus is prevented by the

enhanced Ca²⁺ and regulation of the phytohormone metabolisms in drought-

affected plants (Blum, 1993; Selim & El-Nady, 2011; Song et al., 2008).

Further, the enhanced production of proline and GA3 in MF treated plants

would trigger the Mg²⁺ accumulation that results in the synthesis of chloro­

phyll and/or K⁺ accumulation that is responsible for an increased number of

chloroplasts under drought stress (Reina & Pascual, 2001; Shaddad, 1990).

Such enhancement of chlorophyll and chloroplast number in MF treated

plants would then lead to developing thicker mesophyll tissues (Selim &

El-Nady, 2011). In addition to these adaptive responses as induced by MF

exposure, it also enhances stomatal conductance, increases CO2 concentra­

tion in sub-stomatal region of the leaves, or associated photochemical and

non-photochemical reactions that help to improve drought tolerance of plants

(Javed et al., 2011). The magnetic field exposure also positively influences

the activities of several enzymes of polyamine pathways like ODC and PAL

that help to withstand the adverse effects of biotic stresses or protect the

plants during infection of plants by pathogens (Trebbi et al., 2007). A list of

morpho-physiological or biochemical responses of plant species as triggered

by magneto-priming under different abiotic stresses is summarized in Table

5.2. Apart from the above effects, the magnetic field exposure would also

elicit several other changes such as a mutation in cells of stamen hair of the

inflorescence, formation of longer pollen tubes with a faster germination rate,

along with enhanced cell wall metabolism and changes in the orientation

of the macromolecules (Alexander & Ganeshan, 1990; Baum & Nauman,

1984; Paul et al., 2006).