GLYCINEBETAINE (GB) AS A DETERMINANT OF STRESS TOLERANCE

GB is a zwitterionic, fully N-methyl-substituted de-rivative of Gly that is found in a large variety of microorganisms, higher plants, and animals (Rhodes and Hanson, 1993). At high concentrations, GB does not interfere with cytoplasmic functions and it effi-ciently stabilizes the structure and function of many macromolecules. Thus, it belongs to a group of com-pounds that are known collectively as compatible solutes. GB appears to be a critical determinant of stress tolerance in plants. It is an extremely efficient com-patible solute (Le Rudulier et al., 1984) and its pres-ence is strongly associated with the growth of plants in dry and/or saline environments (Rhodes and Han-son, 1993). The accumulation of GB is induced unde