Growth characteristics of apparently rejuvenated plum shoots

Abstract

SummaryField-grown ‘Pixy’ plum hedgeplants which originated from micropropagules raised in vitro produced shoots whose greater vigour when compared with that of plants originating from conventional sources was characterized by more shoots with spines and more spines per shoot. Severe winter pruning affected shoot growth similarly. There was a general correlation between spininess and the rooting of winter hardwood cuttings, as influenced by source and pruning treatment. The growth of shoots taken in early summer as softwood cuttings was influenced relatively little by stockplant origin or pruning treatment. The addition of phloroglucinol to the culture medium modified the growth of shoot apices repropagated in vitro. At first, phloroglucinol produced growth rates in normal source material equivalent to those of shoots taken from previously micropropagated plants but, in subsequent passages, normal source cultures grew most in the absence of phloroglucinol.