101

Role of Hydropriming and Magneto-Priming in Developing Stress Tolerance

mechanisms that change plant transcriptional, biochemical, physiological, and

epigenetic levels upon stimulus perception (Anderson et al., 2018; Mauch-

Mani et al., 2017). This is known as the priming phase which is followed by

a post-challenge primed phase, where the plant shows a faster and stronger

defense response upon subsequent challenge and has better stress tolerance.

The substances released as an effect of priming are used to generate high-

energy compounds essential for the germination of seedlings (Renugadevi &

Vijayageetha, 2013). The result is activation of different enzymes, production

of metabolites, protein synthesis, improved antioxidant repair mechanism and

biochemical cell repair systems. Overall seed priming promotes germination

rate, seed vigor, photosynthetic efficiency, root length, biomass production

along with efficient performance under an extensive range of environments

and more than a few agronomic and economic advantages. Some of the other

benefits are efficient release from thermo- and photo-dormancy, improved

water use efficiency, early maturity, better nutrient uptake, and high yield

(Hill et al., 2008; Hussain et al., 2016). Better oxidative defense mechanisms

have emerged from primed seeds acquired with enhanced levels of superoxide

dismutase (SOD), glutathione reductase (GR), ascorbic acid (AsA), catalase

(CAT), and peroxidases (POD), late embryogenesis abundant protein (LEA),

dehydrins (DHN), and aquaporins (AQP) (Blokhina, 2003; Chen et al., 2013;

Fashui, 2002; Wechsberg et al., 1995). Many studies have reported better crop

establishment, uniform germination with advanced plant growth and stress

resistance in seedlings, therefore, the productivity of field crops (Farooq et

al., 2005, 2006a, b, 2007, 2008, 2010; Muhammad Farooq et al., 2008, 2006a,

b). Seed priming is a durable process that can be maintained and transmitted

from one generation to another, thus signifying a type of immunological

memory in plants (Lutts et al., 2016; Mauch-Mani et al., 2017). However,

different factors attribute to priming, such as plant species, priming media,

storage conditions, temperature, light, seed characteristics, priming duration,

and aeration.

4.2 MAGNETO-PRIMING INDUCED CHANGES IN PLANTS UNDER

VARIOUS ABIOTIC STRESSES

Magneto-priming is dry seed priming technique that omits the hydration and

dehydration cycle which is inherent for wet priming treatments and allows

storage of seeds at room temperature (Bhardwaj et al., 2012; Kataria & Jain,

2019; Kataria et al., 2019; Thakur et al., 2019). The effect of the magnetic

field, first reported in plants by Krylov & Tarakanova (1960), has received