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Role of Hydropriming and Magneto-Priming in Developing Stress Tolerance

adversely affect growth, leaf thickness, photosynthesis, nitrogen fixation and

yield (Rozema et al., 2002; Turunen & Latola, 2005; Kataria et al., 2014a,

b). The disruption of membrane systems due to increase in O2

•– radical

along with increased malondialdehyde concentration and relative electrolyte

conductivity in leaves of rice plants and cucumber cotyledons have been

reported (Dai et al., 1997; Jain et al., 2004). On the other hand, lower levels

of O2

•– radicals were found in leaves of maize plants that emerged after SMF-

treatment (Shine & Guruprasad, 2012a, b).

The inhibitory effect of ambient UV stress in maize was alleviated by

SMF-pre-treatment (Kataria et al., 2015). In a follow up study, it was seen

that SMF (200 mT for 1 h) treatment of soybean seeds increased plant

height, leaf area, biomass accumulation, hemichrome content in the root

nodules, and improved the PS II efficiency and rate of photosynthesis both in

presence and absence of solar UV in comparison to untreated seeds (Kataria

et al., 2017b). Raipuria et al. (2021) observed that SMF-priming provides

UV-B tolerance to soybean seedlings via increased ROS and NO content;

and up-regulation of α-amylase, nitric oxide NOS, and NR genes during the

seed germination. Kataria et al. (2017b, 2020b, 2021) provided evidence

that SMF-pretreatment increased the tolerance of soybean plants to ambient

and supplemental UV-B radiation in the field conditions through the higher

PSII efficiency, quantum yield of electron transport, performance indices,

rate of photosynthesis and lower MDA, proline, ROS, and antioxidant (AsA,

α-Tocopherol) content which subsequently increase the yield of soybean

plants. Kataria et al. (2020b) also found that SMF-priming of soybean seeds

(200 mT for 1 h) enhanced the CA in the leaves and nitrogenase activity in

root nodules under non-stress and ambient UV-B stress as compared to their

unprimed control plants.

4.3 HYDROPRIMING FOR ABIOTIC STRESS TOLERANCE

Due to sessile nature, plants continuously experience various abiotic stresses

such as salinity, extreme temperature, and drought at different develop­

mental stages. Germination is an important stage that is highly responsive

to vary under different environmental conditions and controlled by various

molecular, biochemical, and physiochemical processes involved in embryo-

genesis (Bewley, 1997; Bewley et al., 2013; Lutts et al., 2016; Rajjou et al.,

2012). Abiotic stresses are often interrelated and cause a series of adverse

changes in morphological, physiological, molecular, and biochemical that

disturb plant growth, development, and production (Hussain et al., 2018).