English

Abstract

Germination is a key event in plant life cycle and imbibition temperature is an important factor for the major reorganization pro- cesses in the germinating seeds. Sub-physiological temperature at this stage affects virtually all aspects of cellular function including protein folding, kinetic parameters of membrane fluidity, protein assembly, and general metabolic processes. In this article we will review the re- search which has been carried out to decipher the basic mechanisms of low temperature (LT) stress with special emphasis on germination. With the better understanding of LT tolerance in some plant species we will also discuss how these attributes can be transferred in the im- portant food crops to attain better germination stamina at sub-physiological temperatures. At germination stage, the cellular machinery in the embryo is not at its proper place and is going through reorganisation and any environmental severity has devastating effects on the fragile plant. But LT resistant species have evolved the ability to acclimatise, with the remodelling of cell and tissue structures and the reprogram- ming of metabolism and gene expression. Metabolic networks are redirected towards the synthesis of cryoprotectant molecules, which in association with other proteins bring about physical and biochemical restructuring of cell membranes through changes in the lipid composi- tion and induction of other non-enzymatic proteins that alter the freezing point of water. Genetic engineering of crops for enhanced seed germination performance will certainly help to achieve optimum agricultural yields..