Origin of Somatic Embryogenesis is Proliferating Root Primordia in Seed Derived Oat Callus

Abstract

The ontogeny of somatic embryos and proliferating root primordia in tissue cultures of mature seeds of oats is described. Callus formation was initiated on developing embryos of mature oat seeds maintained on Murashige and Skoog's medium containing 2mgl‐1 2,4‐dichlorophenoxyacetic acid. The root primordia on subculture medium did not elongate but multiplied by forming new primordia directly from root meristem, after callusing or by cleaving pre‐existing root primordia. In the root meristem region somatic embryogenesis could also occur. The first somatic embryos were observed at the end of the first subculture. Different developmental stages of somatic embryos were histologically identified in the culture. Occasionally shoot buds were formed directly from root primordia. Among 5 tested cultivars Risto had the best response on callus culture medium. 200 shoots/plantlets per gram of a 10‐month culture were obtained on MS germination medium containing 0.01 mgl‐1 ABA and 6% sucrose. Copyright © 1994, Wiley Blackwell. All rights reserved