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Magneto-Priming: A Novel Technique Towards Improved Seed Germinability

the blue light-absorbing flavoproteins are assumed to help several organisms

like birds, insects or plants in perceiving the direction and intensities of the

magnetic field. Upon exposure to blue light, these flavoproteins undergo a

redox cycle of flavins and tryptophan residue that leads to the activation of

radical pair mechanism and this, in turn, results in the perception of magnetic

field (Fay et al., 2019; Mridha et al., 2016; Pooam et al., 2019). Another

possibility “ferrimagnetism hypothesis” indicates that perception of static

magnetic fields is accomplished through its interaction with iron particles,

inorganic iron compounds like iron oxide black or greigite as well as with

phytoferritin or iron-containing proteins of the plant cells.

Though it is well known that enhanced production of cellular ROS would

negatively affect the functioning of plant systems, but the magnetic treatment

causes to reduce ROS production and improve plant growth significantly

under different stresses (Radhakrishnan, 2019). In germinating seeds, ROS

are generated via aerobic metabolisms that occur in mitochondria, chloro­

plasts, peroxisomes, and/or the apoplastic spaces of the cell membrane. The

production of ROS is initiated by the active participation of some enzymes

like xanthine oxidase (XO), superoxide dismutase (SOD), lipoxygenases

(LOXs), membrane bound NADPH oxidase (NOX), amine oxidases (AOs)

or peroxidases (POXs), etc. The reaction chain can be described as there is

a redox-active metal ion present in each enzyme, and the metal ion initiates

the generation of superoxide molecules, and then reduction of superoxide by

the metal ion yields hydrogen peroxide (H2O2) (Bolwell & Wojtaszek, 1997;

Collin, 2019; Messner & Imlay, 2002; Munro & Treberg, 2017; Smirnoff &

Arnaud, 2019). These generated ROS play an important role as signaling

molecules for the major events that happened in germinating seeds including

dormancy breaking. The crucial roles of ROS like H2O2, hydroxyl radical

(•OH^–), superoxide (O2

•–) in seed germination of different crops have been

established by several research (Bhardwaj et al., 2012; Kranner et al., 2010;

Morohashi, 2002; Müller et al., 2009; Schopfer, 2001). H2O2 is the most

common among the ROS. It stays for a long time in the plant systems, and it

can easily diffuse through the cell membrane to reach their action sites from

the actual sites of production. Actually, the redox state of the seed is changed

by the interaction between ROS and the hormones that participate in seed

germination. The participation of these hormones determines the success or

failure of germination through the initiation of the metabolic reactions by

regulating the expression of related genes (Bailly et al., 2008; El-Maarouf-

Bouteau & Bailly, 2008). In this context, it is also thought that there is an

antagonistic effect between gibberellic acid (GA) and abscisic acid (ABA)