Rapid Regeneration of Lettuce from Suspension Culture

Abstract

An efficient method for the regeneration of shoots directly from cell suspensions of three commercial cultivars of lettuce (Lactuca sativa L. cv. Great Lakes 659-700, Salad Bowl, and Prize Head) is described. Cell suspensions were prepared by osterizing cotyledon-derived callus for 60 seconds. The effects of callus quality, light intensity, carbohydrate type and concentration, auxins, and cytokinins on cell growth and differentiation in the suspension culture were examined. Among these factors, callus quality and carbohydrates were the most critical. The optimal medium for regeneration of shoots in suspension culture was SH (Schenk and Hilderbrandt) basal medium containing 1000 mg myo -inositol/liter, 1.5% glucose, 0.44 μ m BA, and 0.54 μ m NAA. The pH of the medium was adjusted to 5.8. Under such condition, hundreds of shoots could be produced from 50 to 55 mg (dry wt) of cell aggregates within 2 weeks. Chemical names used: α-] naphthaleneacetic acid (NAA); indole3-acetic acid (IAA); 6-benzylaminopurine (BA).