Tissue culture of Acacia mangium, Acacia auriculiformis and Acacia hybrid.

Abstract

Explants were cultured from hypocotyls of germinating seedlings and axillary buds of 2-year-old seedlings of A. mangium and A. auriculiformis and their interspecific hybrid. Shoot formation occurred in 80-100% of hypocotyl explants on half-strength MS medium (1/2 MS) with 0-2.0 mg BA/litre. The number of shoots varied depending on the amount of BA added to the medium, the maximum occurring in the presence of 1-2.0 mg BA/litre. When shoots were transferred to 1/2 MS containing IBA and NAA, root formation occurred in 62.5% of shoots from A. mangium and 17.7% of shoots from A. auriculiformis. Shoot formation from the axillary bud explants was compared in both 1/2 MS and MS media with 1 mg BA/litre. In MS medium the rates of shoot formation were: hybrid 80.0%, A. mangium 71.4% and A. auriculiformis 57.1%; and in 1/2 MS medium A. mangium 85.7%, hybrid 75.0% and A. auriculiformis 28.6%. The shoot formation rate of hybrid explants varied from 66.7 to 100% in MS medium and 57.1 to 83.3% in 1/2 MS. The root formation rate for shoots from axillary bud explants in MS medium with 0.2 mg NAA/litre was 69.2% in A. mangium, 38.5% in A. auriculiformis and 71.8% in the hybrid; these rates were higher than for the hypocotyl explants.