The Discovery of Abscisic Acid: A Retrospect

Abstract

Parallel to the discovery of auxin as a growthpromoting hormone in the first half of the last century, it became evident that inhibitors of auxin-induced cell elongation, seed germination and bud growth also existed in plants. Their activity was noticed first in more or less unspecific bioassays, and their natural function remained unknown for a long time. The introduction of paper chromatography in combination with bioassays enabled improved separation of plant extracts and identification of biologically active compounds. By means of these new techniques, a highly active growth inhibitory fraction named 'inhibitor b' was discovered in many plants. Evidence that this fraction seemed also to be involved in abscission processes resulted in the name 'abscisin II', whereas another research group that investigated the possible role of inhibitor b in bud dormancy proposed the name 'dormin'. Great efforts were made to identify the chemical nature of the two compounds. In 1965, it was recognized that abscisin II and dormin possessed the same chemical structure, which received the name 'abscisic acid' (ABA). Soon afterwards the extraordinary role of ABA as a hormone involved in stress reactions and in seed maturation was discovered, whereas its suggested function in abscission and bud dormancy processes has not been well established until now. The name ABA is therefore not adequate with regard to the hormonal functions, but it is acceptable with regard to priority rules.

From Facts and False Routes: How Plant Hormone Research Developed

“…However, as pointed out by Dörffling in this issue (Fig. 4), the discovery of abscisic acid cannot be really separated from IAA, because a typical growth assay was used to isolate a growth inhibitory compound from the ''inhibitor complex ß'' (Dörffling 2015). Moreover, some aspects on auxin determination are presented by Tivendale and Cohen (2015) (Fig.…”

“…In Germany he also contributed with a textbook on plant hormones in the 1980s. His story on some aspects in the history of plant growth regulators (Dörffling 2015) chromatography increased the interest in this compound as a plant hormone (Bakshi and others 2015).…”

An Evolutionarily Conserved Abscisic Acid Signaling Pathway Regulates Dormancy in the Liverwort Marchantia polymorpha

“…In vascular plants, the canonical ABA signaling pathway is employed to establish growth arrest in several developmental contexts as well as in response to abiotic stress responses [49][50][51][52][53][54][55].…”

On the nature of non-protein receptors from the conceptual point of view. Paradigm for abscisic acid

“…Abscisic acid as final product from destruction of carotene. ABA is a biologically active substance (BAS) that was discovered during the 1960s [1][2][3]. Currently a large body of evidence indicates that ABA takes part in the various biochemical and physiological processes, including seed development and germination, seedling growth, stomatal movement, and abiotic stresses, such as drought, high salinity, chilling, and pathogen [4][5][6][7].…”