Cytokinin-like activity of N,N '-diphenylureas. N,N '-bis-(2,3-methylenedioxyphenyl)urea and N,N '-bis-(3,4-methylenedioxyphenyl)urea enhance adventitious root formation in apple rootstock M26 (Malus pumila Mill.)

Vegetative propagation of cuttings is a widespread method to multiplicate p lants. Adventitious root formation is a key step in vegetative propagation and considerable progress has recently been made in understanding root form ation. But. in spite of the efforts made, no new rooting treatments have be en developed. Here, we report for the first time. that N,N'-bis-(2,3-methyl enedioxyphenyl)urea and N,N'-bis-(3,3-methylenedioxyphenyl)urea enhance adv entitious root formation in microcuttings of Malus pumila Mill. rootstock M 26. Roots emerge without auxin supplementation in the darkness, transfer in hormone free medium, or callus formation. With the use of different bioass ays, we also demonstrate that these two diphenylurea derivatives do not sho w cytokinin- or auxin-like activity. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.