Describe the discovery of $ABA$.

(N/A) With the progression in research on plant growth regulators,three independent researchers reported the purification and chemical characterization of three kinds of inhibitors during the mid-$1960$s,namely: inhibitor-$B$,abscission-$II$,and dormin.
Later,all three were proved to be chemically identical in nature and were collectively named Abscisic Acid $(ABA)$.