Allelochemical autotoxicity in the emergent wetland macrophyte Juncus effusus (Juncaceae)

Abstract

Bioassays for allelochemical toxicity of aboveground Juncus effusus tissues were conducted with seeds and seedlings of Eleocharis obtusa and Scirpus cyperinus, two emergent sedge species (Cyperaceae) found sympatric with J. effusus, and with seeds and seedlings of J. effusus itself to evaluate potential autotoxicity. Bioassays were performed under controlled, axenic conditions with aqueous shoot extract treatments simulating in situ dissolved organic carbon concentrations. With respect to the two sedge species, neither shoot development nor seedling biomass accrual was significantly suppressed by lyophilized whole extracts from J. effusus. Although the extracts induced no significant reduction in growth of E. obtusa or S. cyperinus, biomass-specific chlorophyll a concentration was significantly reduced in E. obtusa seedlings. In contrast, seedlings of J. effusus exhibited significant reductions of biomass and chlorophyll a concentrations, and seedling shoot development was retarded in response to leachate exposure. Results of the present study suggest that J. effusus seedlings possess autotoxic sensitivity to extracts of dead, aboveground tissues of adult plants.

Allelopathy of Aquatic Autotrophs

“…effusus (Della Greca et al, 1998). Leachates of dead, aboveground tissue of adult plants are autotoxic to seedlings (Ervin and Wetzel, 2000). Whether autotoxicity is based on the abovementioned algicidal compounds or other secondary metabolites present in this species (Corsaro et al, 1994;Della Greca et al, 1992a remains to be elucidated.…”

“…Whether autotoxicity is based on the abovementioned algicidal compounds or other secondary metabolites present in this species (Corsaro et al, 1994;Della Greca et al, 1992a remains to be elucidated. Autotoxicity toward seedlings in this otherwise vegetatively spreading plant may benefit temporal dispersal of seedling establishment and population regeneration after disturbance (Ervin and Wetzel, 2000). A very detailed review on autotoxicity, mainly in terrestrial plants, and its ecological significance was presented recently in this joumal (Singh et al, 1999).…”

Searching for allelopathic effects of submerged macrophytes on phytoplankton—state of the art and open questions

“…Only few studies describe the use of axenic macrophytes (e.g., Pringsheim & Pringsheim, 1962;Forsberg, 1965;Wetzel & McGregor, 1968;Ervin & Wetzel, 2000). Although axenic plants represent an artificial system, they can serve as controls that can then be compared to nonaxenic plants.…”

Elucidation of a Diurnal Pattern of Catechin Exudation by Centaurea stoebe

“…These exuded compounds can modify species competition in favor of donor plants by providing uncontested access to the limited resources (Rice 1984), by increasing chemical nutrient foraging efficiency (Tharayil et al 2009), by preventing intraspecific competition through autotoxicity (Ervin and Wetzel 2000), and by facilitating root navigation in soil (Falik et al 2005). Centaurea stoebe, spotted knapweed, is a noxious and economically destructive exotic weed that has invaded 2.9 Mha in North America (DiTomaso 2000).…”