Allelopathy as an evolutionary game

Abstract

In plants, most competition is resource competition, where one plant simply preempts the resources away from its neighbors. Interference competition, as the name implies, is a form of direct interference to prevent resource access. Interference competition is common among animals that can physically fight, but in plants, one of the main mechanisms of interference competition is allelopathy. Allelopathic plants release cytotoxic chemicals into the environment which can increase their ability to compete with surrounding organisms for limited resources. The circumstances and conditions favoring the development and maintenance of allelochemicals, however, are not well understood. Particularly, despite the obvious benefits of allelopathy, current data suggest it seems to have only rarely evolved. To gain insight into the cost and benefit of allelopathy, we have developed a 2 2 matrix game to model the interaction between plants that produce allelochemicals and plants that do not. Production of an allelochemical introduces novel cost associated with both synthesis and detoxifying a toxic chemical but may also convey a competitive advantage. A plant that does not produce an allelochemical will suffer the cost of encountering one. Our model predicts three cases in which the evolutionarily stable strategies are different. In the first, the nonallelopathic plant is a stronger competitor, and not producing allelochemicals is the evolutionarily stable strategy. In the second, the allelopathic plant is the better competitor, and production of allelochemicals is the more beneficial strategy. In the last case, neither is the evolutionarily stable strategy. Instead, there are alternating stable states, depending on whether the allelopathic or nonallelopathic plant arrived first. The generated model reveals circumstances leading to the evolution of allelochemicals and sheds light on utilizing allelochemicals as part of weed management strategies. In particular, the wide region of alternative stable states in most parameterizations, combined with the fact that the absence of allelopathy is likely the ancestral state, provides an elegant answer to the question of why allelopathy seems to rarely evolve despite its obvious benefits. Allelopathic plants can indeed outcompete nonallelopathic plants, but this benefit is simply not great enough to allow them to go to fixation and spread through the population. Thus, most populations would remain purely nonallelopathic.

Invasive Alien Species as a Potential Source of Phytopharmaceuticals: Phenolic Composition and Antimicrobial and Cytotoxic Activity of Robinia pseudoacacia L. Leaf and Flower Extracts

“…Since the black locust is a nitrogen-fixing plant, it can cause changes in indigenous vegetation towards ruderal and nitrophilous species [ 13 ]. Moreover, many studies report the allelopathic potential of this species [ 14 , 15 , 16 ], which is considered one of the most important mechanisms responsible for the spread of IAPS in new areas [ 17 , 18 , 19 ]. In particular, these studies highlight the efficacy of whole extracts [ 20 , 21 ] or individual phenolic compounds [ 14 ] extracted from different parts of the plant in inhibiting the germination and growth of other plant species.…”

Efecto alelopático de hojarascas de Eucalyptus globulus y Pinus halepensis en plantas silvestres Altoandinas, Perú

“…Del mismo modo, la diversidad de especies según el índice de Shannon fue mayor en el grupo control, en comparación a los tratamientos con los lixiviados de pino y eucalipto (F = 7.531, gl = 2, P = 0.003) (Figura 4C). El efecto negativo de los aleloquímicos sobre la diversidad de especies se restringiría a la etapa juvenil de las plantaciones; en el que, al estar en pleno crecimiento, la demanda por los nutrientes es alta (McCoy et al, 2022). Posterior a esta etapa, se puede evidenciar una recuperación de la diversidad (Cao et al 2010) En el Perú, la especie que en mayor medida se ha plantado es el eucalipto (Luzar 2007), dejando pasar por alto el efecto negativo que tendría en la biodiversidad.…”

Persistence of Root Exudates of Sorghum bicolor and Solidago canadensis: Impacts on Invasive and Native Species

“…Second, the results suggest residual Solidago canadensis exudates could help limit certain invaders like Veronica persica through allelopathic interference. Fostering competitive invasive species like Solidago canadensis could aid invader resistance without requiring chemical control [ 2 , 93 ]. Lastly, the results provide baseline data on species-specific allelopathy responses that can inform integrated management programs relying on multiple control techniques.…”