Biostimulatory Impacts of Seed Priming through Botanical Extracts on Crop Production: A Critical Review

Rapid human population increase, food scarcity, and climate change are some of the global challenges in the current scenario. Among these, climate change adversely impacts crop production by creating abiotic stresses such as drought, salinity, and metal toxicity. Seed emergence, the critical stage in crop development, is highly vulnerable to these abiotic stresses. Therefore, short-term approaches to increase seed germination and the initial growth of plants were investigated in advance as a solution. Seed priming is indeed a pre-sowing treatment of seeds. It is a technique used to enhance the germination and early growth of seeds by exposing them to controlled hydration and sometimes other treatments before planting. Seed priming considered a low-cost, eco-friendly, and sustainable technique to promote seed germination and the initial growth of plants. Though various priming methods are available, this review discusses only botanical extracts (both seaweed and plant extracts) used as priming agents in seed priming. Among the seaweed extracts, green and brown algae species such as Ascophyllum nodosum, Sargassum spp., and Ulva spp. enhanced the crop performances even under stress conditions. In addition, leaf extracts derived from drumstick (Moringa oleifera) and neem (Azadirachta indica) are widely used to increase the crop production under stress and non-stress environments. Furthermore, in this review discussed about priming mechanism, different extraction methods and bioextracts behavior under diverse agroecosystems are discussed in detail.