International Journal of Horticulture, 2025, Vol.15, No.5, 242-256 http://hortherbpublisher.com/index.php/ijh 245 These priming techniques can be tailored to specific crop species and anticipated stress conditions. Their success depends on key variables such as priming duration, temperature, seed quality, and post-priming storage (Paparella et al., 2015). This technique follows a defined sequence of physiological stages: initial imbibition under controlled conditions, metabolic activation of enzymes and gene expression, and a drying phase to revert the seed to a storable state. This cycle induces a physiological “primed state” that improves the seed’s readiness to respond to environmental challenges and accelerates early growth under stress conditions (Wojtyla et al., 2016). Optimizing these parameters is essential to ensure consistency and maximize benefits across genotypes and environments. 3.2 Types of priming Several seed priming techniques have been developed to enhance the resilience of horticultural crops under abiotic stress. These methods vary in complexity and mode of action, but all aim to improve the physiological and biochemical preparedness of seeds before germination. “Hydropriming”, which consists of soaking seeds in water, is the most basic and accessible technique (Koushal et al., 2024). The main disadvantage of hydropriming lies in the difficulty of precisely controlling the degree of seed hydration, which often results in uneven water uptake among seeds and consequently leads to non-uniform germination (Lutts et al., 2016). “Osmopriming” involves the application of osmotic agents to regulate seed water uptake by lowering the osmotic potential (Ψo) and has been widely applied to enhance drought and salinity tolerance through osmotic adjustment and antioxidant activation(de Oliveira and Gomes-Filho, 2016). Polyethylene glycol (PEG) is the most widely used osmotic agents due to its non-toxic nature and high molecular weight, which prevents cellular penetration (Lei et al., 2021). However, the high viscosity of PEG solutions can restrict oxygen diffusion during treatment and complicate the retrieval of seeds post-priming (Paparella et al., 2015). Alternatively, inorganic salts such as NaCl, CaCl2 and KNO3 have been employed as cost-effective and user-friendly priming agents (Castañares and Bouzo, 2018). Yet, their application demands careful calibration of both concentration and duration, as the release of ions into the solution may induce phytotoxicity and negatively impact seed viability (Paparella et al., 2015). “Hormonal priming” uses phytohormones such as gibberellic acid (GA3), abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) to activate hormonal signaling pathways related to stress tolerance (Farooq et al., 2019). The main limitation of this technique lies in the variation of treatment conditions required for different plant species (Rhaman et al., 2020). “Biopriming”, an approach gaining prominence in sustainable agriculture, incorporates beneficial microbes like plant growth-promoting rhizobacteria (PGPR), arbuscular mycorrhizal fungi or Trichoderma spp (Chakraborti et al., 2022). These organisms not only promote germination and nutrient uptake but also bolster plant immunity and stress tolerance. However, their practical deployment is constrained by factors such as microbial viability during storage, formulation stability and varying performance under field conditions (Singh et al., 2023). “Nanopriming”, an emerging and technologically advanced method, uses nanoparticles such as ZnO, TiO2 or silver to stimulate antioxidant enzyme activity, improve membrane stability, and enhance signaling under stress conditions (Khan et al., 2023). Redox priming involves priming agents such as hydrogen peroxide (H2O2) or nitric oxide (NO) that precondition the seed’s redox state, thereby strengthening antioxidant systems and improving tolerance to oxidative stress (Hussain et al., 2022). Despite the promising results of these priming methods, especially under controlled environments, there are growing concerns about their ecological and food safety implications. In particular, nanopriming raises issues related to the potential accumulation of nanoparticles in plant tissues, which could pose toxicological risks to humans and animals if residues persist in edible parts (Chaithanya and Rao, 2023). Furthermore, nanoparticles released into agricultural soils may alter microbial communities and affect non-target organisms, potentially disrupting ecosystem dynamics (Shelar et al., 2023). Biopriming, although generally considered safe, field
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