IDENTIFICATION OF PLANT-GROWTH INHIBITORY PRINCIPLES IN AILANTHUS-ALTISSIMA AND CASTELA-TORTUOSA

A methanol extract of Ailanthus altissima and a methylene chloride ext ract of Castela tortuosa exhibited plant growth inhibitory activity ag ainst Brassica juncea, Eragrostis tef, and Lemna minor. Ailanthone and chaparrinone were identified as the active constituents in A. altissi ma and C. tortuosa, respectively. In the bioassays with B. juncea, E. tef, and L. minor ailanthone inhibited growth by 50% (I-50) at 0.9, 2. 6, and 21 mu M, respectively, and the I-50 values for chaparrinone in these three bioassays were 0.9, 2.1, and 4.2 mu M, respectively. In a greenhouse test ailanthone exhibited inhibitory activity against sever al weed species, and it was more effective postemergent than preemerge nt.