Abscisic 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.
