Allelopathy and Allelochemicals of as an Invasive Plant Species.

(Lam.) de Wit is native to southern Mexico and Central America and is now naturalized in more than 130 countries. The spread of is probably due to its multipurpose use such as fodder, timber, paper pulp, shade trees, and soil amendment. However, the species is listed in the world's 100 worst invasive alien species, and an aggressive colonizer. It forms dense monospecific stands and threatens native plant communities, especially in oceanic islands. Phytotoxic chemical interactions such as allelopathy have been reported to play an important role in the invasion of several invasive plant species. Possible evidence for allelopathy of has also been accumulated in the literature over 30 years. The extracts, leachates, root exudates, litter, decomposing residues, and rhizosphere soil of increased the mortality and suppressed the germination and growth of several plant species, including weeds and woody plants. Those observations suggest that is allelopathic and contains certain allelochemicals. Those allelochemicals may release into the rhizosphere soil during decomposition process of the plant residues and root exudation. Several putative allelochemicals such as phenolic acids, flavonoids, and mimosine were identified in The species produces a large amount of mimosine and accumulates it in almost all parts of the plants, including leaves, stems, seeds, flowers, roots, and root nodules. The concentrations of mimosine in these parts were 0.11 to 6.4% of their dry weight. Mimosine showed growth inhibitory activity against several plant species, including some woody plants and invasive plants. Mimosine blocked cell division of protoplasts from hort. ex E. Vilm. between G and S phases, and disturbed the enzyme activity such as peroxidase, catalase, and IAA oxidase. Some of those identified compounds in may be involved in its allelopathy. Therefore, the allelopathic property of may support its invasive potential and formation of dense monospecific stands. However, the concentrations of mimosine, phenolic acids, and flavonoids in the vicinity of , including its rhizosphere soil, have not yet been reported.