Rejuvenation and micropropagation of adult Acacia mearnsii using coppice material

Abstract

In an attempt to overcome maturation affects and loss of juvenile characteristics, when using adult plant material in vitro, investigations were undertaken into the the use of coppice material, as an alternative. Trees from 5 age groups (2, 4, 6, 8 and 10-years-old, respectively) of Acacia mearnsii were felled to a height of 1.5 m. After 3 weeks, coppice was noted on the stumps of trees of all the age groups. A linear degree of coppice production was noted between the age groups, with the greatest coppice production being on the 2-year-old trees and least on the 10-year-old trees. Decontamination of the coppice was successful and multiple shoot production was obtained from all age groups on Murashige and Skoog (MS) medium supplemented with 2.0 mg l−1 benzyladenine (BA). Various sucrose concentrations were investigated and it was noted that greater shoot production occurred with increased sucrose concentrations (20 and 30 g l−1). It is evident that rejuvenation of mature tissue can be achieved through the use of coppice material. This technique can now be used for future breeding programmes for the black wattle.