effect of nanoparticles on seed priming

Introduction: seed priming is defined as a pre-sowing technique of seeds to enhance seed germination and the production of high seedling vigor in which seeds coated with different materials )such as water, mineral salts including zinc sulfate, magnesium chloride, manganese sulfate, sodium chloride, and sodium sulfate( at the optimum concentration for a specific period under controlled conditions (ghassemi-golezani et al. 2012; ibrahim 2016). however, conventional seed priming agents are not as stable and are required in large quantities, where most of them will be discarded as waste and pollute soil as well as water, leading to the need for repeated use of these seed growth enhancers. therefore, nanoparticles have been introduced as a new and efficient seed priming and growth enhancer agents in different recent researches (singh et al., 2021). seed nanopriming is significantly different from conventional seed priming because it maiknly uses water (hydropriming) or solutions containing elements (nutrients, hormones, or biopolymers) that adsorb on the seed (imtiaz1 et al., 2023). therefore, the aim of the present study is to introduce the seed nanopriming technique and its advantages to enhance seed germination and improve seed quality. materials and methods: the present article has been prepared by studying and reviewing the published literature on nanopriming. results and discussion: seed nanopriming is a novel approach in agriculture in which nanoparticles are applied for priming. carbon, ceramic (metal oxides), metal (such as silver, titanium dioxide, zinc, iron and copper nanoparticles),, and polymeric nanoparticles are used in seed nanopriming to facilitate plant growth and development (imtiaz1 et al., 2023). moreover, less concentration of nanoparticles is required to improve seedling vigor of various crops, compared to conventional seed priming agents (singh et al., 2021). seed priming is advantageous due to the slow diffusion of nps into the seed and the alternate hydration and dehydration process may have lead nps to be adsorbed at biomolecules which ultimately enhanced seedling elongation and biomass (maswada et al. 2018). it is known that the germination rate of nano-primed seeds is higher than that of seeds primed using other methods. therefore, by simply soaking the seeds in nanoparticles solution, a higher germination rate is achieved. the nano solution also affects the subsequent physiological processes of the plant, so that the optimal concentration increases crop yields and growth rates without polluting the environment (song and he, 2021). numerous studies have evidently shown the positive influence of nms as seed priming on germination and the positive effect of nms on plant growth at specific concentrations and sizes in most plant species (hassanisaadi et al., 2022). for example, acharya et al. (2020) reported that compared to unprimed seeds, nanopriming with agnps improved seed germination, emergence, and seedling growth rate. the use of nano-anatase on parsley seeds increased the germination percentage, germination rate index, root and shoot length, fresh weight, vigour index, and chlorophyll content of the seedlings (dehkourdi et al., 2013). itroutwar et al (2020-2021) reported the application of fe2o3 and zno nps as priming agents for seed quality improvement in rice and maize. nanopriming by activating metabolic enzymes such as amylase, protease and lipase may coordinate seed germination and increase seedling viability (ali et al., 2020). in addition, nanoparticles induce the production of ros to promote early embryo growth and development, and slowly penetrate into seeds to regulate metabolic processes. in general, seed germination requires an optimal ros concentration during the oxidative window for germination . ros bursts cause free radical-mediated polymer degradation and subsequent cell wall loosening, which is essential for cell proliferation in plant growth. however, the accepted possible mechanisms for promoting seed germination after nanopriming are: (1) hydroxyl radicals are produced to loosen cell walls and form small pores on the seed surface to increase water absorption, and (2) the increased reactivated ros and increased activity of antioxidant enzymes significantly alter antioxidant metabolism (song and he, 2021). conclusion: nanopriming as an effective technique can increase the seed germination rate. but there are also potential challenges in this field that need to be considered, for example, whether subsequent seeds will turn into seedlings or not, and the possibility of metal toxicity and environmental pollution, which require time and money to observe.