Seed priming: New vistas and contemporary perspectives

Abstract

Seed germination and uniform plant stand in field are of most critical stages of crop growth that determine the final yield. Crop production is very often hampered under suboptimal conditions, and such effect is principally attributed to poor or uneven germination and unsynchronized seedling emergence. Seed priming is an age-old and simple but effective technique to enhance germination percentage and speed and to achieve uniform plant stand and better yield in a wide range of environmental conditions. However, various priming protocols differ in their effectiveness depending on a complex interaction of factors including plant species or genotypes, water potential of priming agents, duration of treatment and environmental features. Basically priming is physiological advancement of seeds, and it involves the initiation of pre-germinative metabolisms through soaking of seeds in water or solution of other conventional priming agents under controlled condition. But, adjusting of the priming protocols by accurate timing to stop the treatment followed by rapid drying is of major importance to overcome the problem of seed storability due to prolonged treatment. The use of hydrotime analysis or digital image technology has been specified to be useful for optimization of priming protocols. As an alternative to the conventional methods and under the context of contemporary issues of agricultural pollution, the use of physical methods or nanoparticles for seed priming has been evidenced to be advantageous in several aspects. Though these latest methods of priming are receiving great attention by researchers in recent times, the detailed physiological and molecular mechanisms of seed priming with physical methods and/or nanoparticles and their impact on crop plants and environment as well as on human health still remain to be fully explored.