(+/-)-Abscisic acid

DescriptionAbscisic Acid (ABA) is a phytohormone, a naturally occurring compound in plant. ABA is regarded as an inhibitor of plant growth and therefore usually used as a growth retardant in plant tissue culture. To date, ABA has been primarily used to promote the maturation of somatic embryos and the synthesis of storage reserves in embryos during maturation. ABA also acts as a controlling factor of germination and dormancy in somatic embryos and is generally used to induce somatic embryos into a quiescent state during plant tissue culture and synthetic seed studies. ABA stimulates the stomatal closure, thereby reducing transpirational water loss. Thus, it could be used as an anti-transpiration during the acclimatization of tissue culture-raised plants.

Usesabscission-accelerant; kinetin neucleotide synthesis inhibitor

UsesAbscisic acid (ABA) is an isoprenoid plant hormone (phytohormone) synthesized in all parts of plants and involved in many plant developmental processes. ABA is involved in establishing dormancy and regulation of stress responses. ABA inhibits fruit ripening, seed germination, photosynthesis and kinetin biosynthesis.

PreparationThe initial precursor for the synthesis of abscisic acid (ABA) is mevalonic acid (MVA, 3,5-dihydroxy-3-methylvaleric acid). After the formation of farnesyl pyrophosphate (FPP, C15) from MVA, there are two pathways: ① C15 direct pathway: Dehydrogenation and cyclization isomerization produce α- or γ-azinoethanol, which then produces α- or γ-azinoacetic acid (α- or γ-INAA), finally generating ABA. This pathway is mainly found in fungi. ② C40 indirect pathway: First, C40 carotenoids (xanthoxin) are synthesized, then cleaved by photo- or biological oxidation to C15 xanthoxin (XAN), which is then converted to ABA. This pathway is mainly found in higher plants. ABA metabolism also has two pathways: oxidation, where 6-hydroxymethylabscisic acid (HMABA) is converted to safflower stigmataic acid (PA), and then reduced to dihydrosafflower stigmataic acid (DAP); and conjugation. Common abscisic acid esters include abscisic acid glucoside (ABAGE) and abscisic acid glucoside (ABAGS). Dihydrosafflower bean curd acid-4′-O-β-D-glucoside (DPAGS) is found in high amounts in some plants and is also a metabolite of ABA.