The subcellular basis of seed priming.

Abstract

Seed priming is a commercially used technique for improving seed germination and vigour. It involves imbibition of seeds in water under controlled conditions to initiate early events of germi- nation, followed by drying the seed back to its initial moisture content. This review article summa- rizes the recent information available on the various subcelluar processes associated with priming which lead to seed enhancement. The paper discusses the role of synthesis of specific proteins in re- sponse to priming. The effect of priming on DNA repair, gene expression and synthesis of new mes- sage and protein synthesizing machinery are included. The enhancement in the energy metabolism of the cell by priming and the effect of priming in advancing and synchronizing the stage of the cell cycle are discussed. The article also includes information on the role of priming in specific cases, such as alleviation of dormancy in thermosensitive crops which require ethylene. The relationship between seed longevity and priming and methods to prolong longevity, wherever required after priming and the role of desiccation-related proteins, which accumulate during these treatments are also discussed. An illustration summarizing the information on all the metabolic processes which could possibly contribute towards the enhancement in seed performance achieved by priming is included. The paper identifies areas where information is lacking and potential for more in-depth research exists.