Abstract:There were two different stages during the root regeneration from the anther derived spear of Asparagus officinalis L. c v. Marry Washington 500, the root primordia differentiation, and the development stage of root primordia into young root. Differentiation of root primordia was enhanced by amplified nutrient supplement and lowered NAA concentration, both of which were favorable to callus formation and sustained decrease of endogenous ABA at the transection of the base of the spear. Moreover, further development of the root primordia was promoted by appropriate limitation of water supply and by effective aeration.