Plant Regeneration from Friable Embryogenic Callus and Cell Suspension Cultures of Zea mays L.

Abstract

Sectors of a soft, friable, mucilaginous and highly embryogenic callus appeared in embryogenic callus cultures obtained from the scutella of Zea mays L. (maize, commercial hybrid Dekalb XL82) immature embryos. This callus produced globular somatic embryos in very large numbers on the callus maintenance medium and its various modifications. However, the degree of organization in the callus could not be reduced by media alterations, without affecting its embryogenic potential. Stable, rapidly growing and well dispersed cell suspension cultures were obtained from the established friable embryogenic callus. The suspension cultures were comprised of small groups of embryogenic cells, some of which elongated, developed thick walls and ceased to divide. Somatic embryos up to the early scutellar stage were obtained when the suspension cultures were plated on agar-solidified N 6 medium containing low concentrations of 2,4-D (0.1−0.2 mg · 1 −1 ). Upon transfer to appropriate agar media somatic embryos in the friable callus, as well as those formed in plated suspension cultures, developed to maturity, and germinated to produce green plants which were successfully transferred to soil.