Prevention of shoot-tip necrosis in shoot cultures of chestnut and oak

Abstract

Shoot-tip necrosis occurs during the rooting of chestnut and oak cultures. In some cultures, the role of apical dominance is taken over by one of the lateral buds, generally that nearest the apex, and the plant survives. Attempts were made to prevent necrosis by adding a low concentration of 6-benzyladenine (BA) to the rooting medium and, whilst necrosis was to a large extent avoided, the rooting rates fell considerably. Excision of the shoot-tip and application to the cut end of a drop of 25 mg l −1 BA in agar induced axillary growth. The optimum time for carrying out decapitation and BA treatment was after 10 days in the rooting medium. It is suggested that the cause of shoot-tip necrosis is the absence of cytokinin from the rooting medium linked with the root-inducing auxin treatment.