Effect of Abscisic Acid and High Osmoticum Concentration on the Induction of Desiccation Tolerance in Microspore-derived Embryos of Chinese Cabbage (Brassica campestris L.).

Abstract

Induction of desiccation tolerance by abscisic acid (ABA) and osmotic stress was investigated in microspore-derived embryos of Chinese cabbage. Exogenous application of ABA was effective for germination and plant regeneration from dry embryos whose water content decreased to approximately 10% by transfer to a series of desiccators in which the relative humidity remained constant. Induction of desiccation tolerance depended on the ABA concentration, but not on the genotype. The maximum percentages of germination (87.60%) and plant regeneration (46.30%) were obtained in the embryos treated with 10μ ABA. Though osmotic stress by high concentration of sorbitol also induced desiccation tolerance, its effectiveness was less appreciable than that of ABA. On the other hand, all the embryos lost their viability after desiccation, when they were not treated with ABA or exposed to osmotic stress. The dry embryos treated with ABA were able to regenerate into plants in soil. Protein analysis revealed that ABA and osmotic stress increased the accumulation of seed storage proteins in microspore-derived embryos.