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Role of Hydropriming and Magneto-Priming in Developing Stress Tolerance

et al., 1998). The crucial technique of hydropriming is drum priming, which

comprises a drum enclosed with seed coupled with a boiler creating vapors

that condense and water droplets form in the drum (Warren & Bennett, 1997).

Many studies have stated improved stand establishment, seed vigor, and

yield under suboptimal or optimal conditions along with three to four-fold

increases in germination as compared to non-primed seeds. Some studies

explained improved seed germination by hydropriming in wheat under saline

conditions (Afzal et al., 2007; Harris et al., 2001; Nawaz et al., 2016; Roy &

Srivastava, 1999), chickpea (Harris et al., 1999; Kamithi et al., 2016; Kaur

et al., 2002), lentil (Ghassemi et al., 2008), safflower (Ashrafi & Razmjoo,

2010; Bastia et al., 1999), mountain rye (Ansari & Zadeh, 2012), water­

melon (Sung & Chiu, 1995), pearl millet (Kumar et al., 2002). Hydropriming

was effective in enhancing vegetative and reproductive growth stages and

seedling emergence in maize (Dezfuli et al., 2008; Mohammadi et al., 2008;

Nagar et al., 1998). Several food crops coriander, wheat, Allium porrum and

in desert plants like cacti (Dubrovsky, 1996) showed synchronized early

germination after hydropriming. Similarly, improved seed germination was

observed in onion (Caseiro et al., 2004) cauliflower (Jisha et al., 2013),

and in mustard (Srivastava et al., 2010). Therefore, hydropriming provides

improved seedling emergence seed germination, and productivity of field

crops that can be explained by the rapid emergence of shoots and roots, and

better tolerance under adverse conditions (Lee-Suskoon et al., 1998).

4.3.1 SALT

Salt stress is one of the leading problems and major growth-limiting factors in

agriculture, with one-third of the world’s land affected by salinity (Flowers &

Colmer, 2008). Other factors such as nonsystemic irrigation, natural weath­

ering, or intense agriculture also contribute to salt stress (Hasanuzzaman &

Fotopoulos, 2019). The excess build-up of salts reduces water potential in

plants, as consequence plants don’t get access to water (Munns et al., 2006).

Further reduction of water and nutrient uptake due to ion toxicity is observed

(Chinnusamy et al., 2005). The impact of salinity includes, reduced water

and nutrient uptake, altered rate of respiration, reduced rate of photosyn­

thesis, lowered transpiration, ion toxicity, and affects stomatal conductance.

When a plant is exposed to salinity, firstly the osmotic (hyperosmotic) stress

happens due to excess sodium in the root zone, followed by ionic (hypertonic)

stress due to altered concentration of essential nutrients (Munns et al., 2006).

An increase in sodium levels reduces potassium ion influx and disturbs the