Meta-topolin [6-(3-hydroxybenzylamino)purine] is a new class of cytokinin. It was first isolated from poplar leaves. The metabolism of meta-topolin is similar to that of other cytokinins. Just as zeatin and BAP, meta-topolin may undergo ribosylation at position 9 without any effect on it's activity. The shoot production in media with BAP and meta-topolin is very similar, however, after transfer of the seedlings to soil, the shoots produced with meta-topolin produce better roots.
Werbrouck, M. Strnad, H.A Van Onckelen and P.C. Debergh, Meta-topolin, an alternative to benzyladenine in tissue culture?. Physiol. Plant. 98: 291-297 (1996).
J. Holub, J. Hanus, D.E. Hanke and M. Strnad, Biological activity of cytokinins derived from ortho- and meta-hydroxybenzyladenine. Plant Growth Reg. 26: 109-115 (1998).