There are two distinctive actions of abscisic acid (ABA) on plant. One is per-formed through its influence on protein or nucleic acids to induce slow reaction,while the other is through its action on membrane to cause fast reaction. The molec-ular mode of ABA action is an important problem in phytohormone and stress physi-ology. After Hornberg and Weiler reported ABA bound protein, similar reports couldhardly be found. However, Lea et al. and Stillwell et al.proved that ABA could There are two distinctive actions of abscisic acid (ABA) on plant. One is per-formed through its influence on protein or nucleic acids to induce slow reaction, while the other is through its action on membrane to cause fast reaction. The molec-ular mode of ABA action is an important problem in phytohormone and stress physi -ology. After Hornberg and Weiler reported ABA bound protein, similar reports could have been found. However, Lea et al. and Stillwell et al .proved that ABA could