Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Allelopathic mechanisms in community resistance to exotic plants invasions: allelopathic effects of Pinus densiflora Siebold and Zucc. and P. thunbergii Parlat. on the exotic invasive plant Rhus typhina L.

Abstract

In laboratory bioassay and pot culture, we tested the allelopathic effects of fresh leaf and stem aqueous extracts from the native species Pinus densiflora Siebold and Zucc. and the introduced species Pinus thunbergii Parlat. (origin East Asia) on the seed germination and seedling growth of exotic plant Rhus typhina L. In laboratory bioassay, the allelopathic inhibitory effects of P. densiflora were stronger than P. thunbergii, on the seed germination of R. typhina (except germination speed index (GSI) at high (0.1 g/mL) concentrations). Consistent with the laboratory bioassays, in pot culture experiments also the P. densiflora showed stronger inhibitory effects than P. thunbergii on seedling biomass accumulation of R. typhina. Further, we selected 9-common phenolic acids (p-coumaric acid, protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, ferulic acid, salicylic acid, cinnamic acid) to determine their concentrations in P. densiflora and P. thunbergii soils. We found P. densiflora secreted more allelochemicals (except vanillic acid) into its surrounding soil compared to P. thunbergii. The results suggested that the allelopathy of some native dominant trees could affect the invasion potential of exotic plants in different forests types, implying that plant-plant interactions may play important role in determining the habitat invasion resistance.