Absorption of momilactone A and B by Arabidopsis thaliana L. and the growth inhibitory effects

Although most allelochemicals can potentially cause growth inhibition in receiver plants, there is little information available about the absorption of these allelochemicals by the receiver plants. The present research describes the absorption of momilactone A and B by Arabidopsis thaliana (L.) and effects of the absorption on Arabidopsis growth. Exogenously applied momilactone A and B inhibited the growth of Arabidopsis hypocotyls and roots at concentrations greater than 10 and 1 μmol/L, respectively. The levels of momilactone A and B in Arabidopsis hypocotyls were approximately 3.2 and 2.4% of momilactone A and B, respectively, in the medium and those in Arabidopsis roots were about 3.9-3.4%, respectively. The absorption rates of momilactone A and B by Arabidopsis were not significantly different. The present research suggests that momilactone A and B may be absorbed in proportion to their applied levels, and the growth inhibitory effects of momilactone A and B may also correlated with their endogenous levels. However, the effectiveness of momilactone B on growth inhibition was much greater than that of momilactone A, and the sensitivities of hypocotyls to momilactone A and B were greater than those of roots. This is the first report describing the absorption of potent rice allelochemicals, momilactone A and B by receiver plants.