PROMOTION BY PHLOROGLUCINOL OF ADVENTITIOUS ROOT-FORMATION IN MICROPROPAGATED SHOOTS OF ADULT WILD CHERRY (PRUNUS-AVIUM L)

Micropropagated shoots of wild cherry (Prunus avium L.) produced roots in auxin-free medium. Phloroglucinol (PG) increased the proportion of shoots that rooted, while phloretic acid reduced this response in med ium with or without PG, and cancelled the promotive effect of PG. Conc entration of PG also significantly affected rooting in media with and without auxin. The proportion of shoots rooting in media containing au xin, or auxin plus PG, increased with the number of successive subcult ures, but the proportion that rooted with PG alone was unaffected by t he number of subcultures. Before the shoots had become responsive to a uxin, 1 mM PG was more effective than auxin in inducing root formation .