Regulation of Ethylene Biosynthesis1

Ethylene has long been known to have a profound effect on plants (1). The early use of smoke or of burning incense as a ripening agent is undoubtedly attributable to the ethylene content. Following the advent of sensitive gas chromatographic instruments in the early 1960's, postharvest physiologists established the essential role of ethylene as a ripening hormone (1, 30). Demonstration of the natural function of ethylene in fruit ripening has stimulated the search for other functions. As the realization has grown that ethylene is a naturally produced plant hormone, so has the list of processes which it is known to regulate. The various effects of ethylene on plants or plant parts include growth inhibition, root initiation, fruit degreening, flower initiation, modification of flower sex expression, stimulation of fruit growth, initiation of fruit ripening, participation in plant disease resistance, promotion of leaf, flower and fruit abscission and dehiscence, release of seed and bud dormancy, release of apical dominance and regulation of tissue proliferation. At each stage of crop production, ranging from germination and propagation to harvest and postharvest handling, there are plant processes subject to modification by ethylene.