Hardening Treatments Increase Survival of Synthetically-coated Asexual Embryos of Carrot

Abstract

Abstract Asexual embryos of carrot (Daucus carota L.) were initiated from cell suspensions and hardened by treatments with high sucrose (12% as compared to 2%), high inoculum density (0.8 as compared to 0.4 g/25 ml), or chilling (4°C the last 3 days of a 2-week embryo induction phase otherwise carried out at 29°), individually or in combination with 10−6 m abscisic acid (ABA). Carrot embryos either were encapsulated with a water-soluble resin (Polyox WSR-N 750) or nonencapsulated before drying to constant weight. Nonencapsulated embryos did not survive drying. All hardening treatments increased survival of encapsulated embryos. However, survival of embryos treated with ABA plus each of the other 3 hardening treatments was less than expected, assuming additivity. Encapsulated embryos pretreated with ABA and chilling survived 16 days of storage in darkness at 4°.