Fine Structure of Sugarcane (<i>Saccharum</i> sp.) Callus and the Role of Auxin in Embryogenesis¹

Abstract

Histological examination of callus of sugarcane cultivar H50‐7209 ( Saccharum sp. hybrid) revealed all stages of embryoid development when the callus was cultured on modified Murashige and Skoog medium containing 3.0 mg 2,4‐D/liter. It is suggested that the process of dedifferentiation and embryogenic‐cell initiation required relatively high auxin concentrations. Lower auxin concentrations may be required for advanced embryogenesis stages. Plantlet differentiation occurred only in the absence of auxin. Callus on auxin‐free medium showed no dedifferentiation or embryogenesis. We suspect that the origin of the individual sugarcaue plants in this study is from single cells. If so, mutant induction and selection could yield true mutant plants.