Allelopathy and Allelochemicals of Leucaenaleucocephala as an Invasive Plant Species

Abstract

Leucaena leucocephala (Lam.) de Wit is native to southern Mexico and Central America and is now naturalized in more than 130 countries. The spread of L. leucocephala 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 L. leucocephala has also been accumulated in the literature over 30 years. The extracts, leachates, root exudates, litter, decomposing residues, and rhizosphere soil of L. leucocephala increased the mortality and suppressed the germination and growth of several plant species, including weeds and woody plants. Those observations suggest that L. leucocephala 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 L. leucocephala. 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 Petunia hybrida hort. ex E. Vilm. between G1 and S phases, and disturbed the enzyme activity such as peroxidase, catalase, and IAA oxidase. Some of those identified compounds in L. leucocephala may be involved in its allelopathy. Therefore, the allelopathic property of L. leucocephala may support its invasive potential and formation of dense monospecific stands. However, the concentrations of mimosine, phenolic acids, and flavonoids in the vicinity of L. leucocephala, including its rhizosphere soil, have not yet been reported.

Evolution of the Secondary Metabolites in Invasive Plant Species Chromolaena odorata for the Defense and Allelopathic Functions

“…The biosynthesis of some secondary metabolites is induced or synthesized de-novo under certain circumstances. Many of these secondary metabolites in the invasive plants have been reported to show multiple functions such as anti-herbivore, anti-fungal, anti-microbial, and allelopathic activity, and contribute to increasing the fitness of the plants in the invasive ranges [ 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. Available information from a large number of publications suggests that C. odorata is allelopathic, and contains the compounds involved in the allelopathy.…”

Exploring the use of chamomile (Matricaria chamomilla L.) bioactive compounds to control flixweed (Descurainia sophia L.) in bread wheat (Triticum aestivum L.): Implication for reducing chemical herbicide pollution

“…In this regard, phenolic compounds and flavonoids are the main allelochemicals of the plant in the ecosystem and play a significant role in allelopathy ( Jacob and Sarada, 2012 ). They affect cell membrane permeability, inhibit cell division, and interfere with several enzyme activities and major physiological processes, such as protein synthesis and metabolism of some other secondary metabolites ( Kato-Noguchi and Kurniadie, 2022 ).…”

Effects of Seedling Size, Stock Type, and Mechanical Site Preparation Method on Initial Survival and Growth of Japanese Larch (Larix kaempferi) Seedlings

“…The mulcher plot was located higher upslope than the bucket plot; therefore, the mulcher plot was expected to have minimal soil moisture and strong winds, potentially resulting in reduced growth of Japanese larch [18,50,51]. In addition, seedling growth may also have been inhibited by allelopathy, caused by the fermentation of the mulch material [52,53]. The plot design of this study was inadequate to detect the effect of MSP, because there was no MSP replication and different MSP plots were placed at different slope locations.…”