Changes in Gene Expression During Ethylene-Induced Leaf Abscission

The natural shedding of leaves takes place at predictable locations on a plant. It is the culmination of a spectrum of physiological and biochemical events which are restricted to precise cellular locations known as abscission zones (Sexton and Roberts, 1982). It is possible to induce leaf abscission prematurely by exposure of the tissue to the plant growth regulator ethylene (Abeles, 1973). Ethylene-induced shedding shares many features in common with the natural process, and there is good reason to believe that this gaseous regulator may influence the timing of leaf fall in vivo (Morgan, 1986).