Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Difference of phytotoxicity between undecomposed and microbially decomposed plant residues.

Abstract

Extracts of fresh and decomposed plant materials of tall goldenrod [Solidago altissima], mugwort [Artemisia vulgaris], Japanese plume-grass [Erianthus sp.], soyabeans, maize and black wattle [Acacia mearnsii] were monitored for phytotoxicity with a bioassay system using lettuce seeds. Extracts of fresh material of all plant species did not suppress germination considerably, with germination remaining between 80 and 100%. Material of S. altissima, A. vulgaris, Erianthus sp., soyabeans and maize which had been decomposing for 1 month caused germination to fall to <50%. However, this inhibitory effect was not observed with plant material which had been decomposing for 3 or 6 months. Root elongation was inhibited to ≤50% with extracts of fresh material of all species, but A. vulgaris and A. mearnsii which had decomposed for 1 month actually promoted the elongation of lettuce radicles, although this effect diminished with longer periods of decomposition.