Allelopathic potential of invasive Ulmus pumila on understory plant species.

In Petriplate bioassay and Pot culture, we studied the allelopathic potential of leaf litter of Siberian elm (Ulmus pumila L.) invasive tree species on the germination and growth of three herbaceous plant native species (Dactylis glomerata L., Trifolium repens L. and Chenopodium album L.) commonly found in riparian understory communities. Two assays were done with leaf litter of U. pumila from riverine ecosystems (i). the effects of aqueous litter extracts in Petri dish assays and (ii). the effect of litter residues in pot experiments. The leaf litter extracts inhibited the radicle growth of D. glomerata and T. repens but did not effect the germination. However in pots, leaf litter inhibited the germination speed of C. album and growth of D. glomerata and T. repens. Our results showed the allelopathic potential of U. pumila litter, which reduced the growth of understory species (T. repens and D. glomerata). In the litter of U. pumila many phenolic compounds (hidroxibenzoic, ferulic, coumaric, protocatechuic, vanillic and rosmarinic acids, and quercetin) were detected.