GROWTH AND INVERTASE ACTIVITY OF SUGAR BEET CALLUS

Summary The nutrient requirements and cultural conditions for the initiation of sugar beet callus from the variety Kawe AA were established so that on a basic Murashige and Skoog nutrient medium containing 1‐0 mg l−1 kinetin, 1‐0 mg l−1 2,4‐D‐(2,4‐dichlorophenoxyacetic acid) and 4% sucrose a fast growing callus was produced. When the subculture period exceeded 3 weeks, the callus and medium became heavily pigmented. At 1.0 mg l−1 kinetin and 0.05 mg 1−1 2, 4‐D, root and shoot production were initiated and the plantlets were eventually isolated. Analysis of the invertase in callus showed both acid and alkaline invertase in the soluble and insoluble fraction. During a subculture the acid invertase activity remained constant but the alkaline invertase increased. There was no effect on the activity of increasing the concentration of sucrose in the medium. The pattern of invertase activity was similar to that found in other tissue cultures and dissimilar to that in intact plants where sugar accumulation was a notable feature.