“…Of the five classical growth regulators, ethylene (Warman and Solomos, 1988;Knee, 1991;PhilosophHadas et al, 1994) and abscisic acid are known to accelerate leaf senescence, the latter especially in conjunction with light (Zhi-Yi et al, 1988;Rodoni et al, 1998). In some species the most potent antagonist of cytokinin is jasmonic acid methylester (Ueda et al, 1981) which is regarded to represent a stress hormone produced, for example, under conditions of drought (Sembdner and Parthier, 1993).…”