Research Center for Biodiversity and Graduate Institute of Ecology and Evolutionary Biology, China Medical University, Taichung, 40402, Taiwan.
*Correspondence author: E. Mail: choumasa@mail.cmu.edu.tw
1Taiwan Endemic Species Research Institute, Nantou, 55244, Taiwan.
Bidens pilosa was used as test species for greenhouse and laboratory experiments. The leaves powder of R. formosanum mixed in soil at 1% concentration, moderately suppressed the growth of B. pilosa seedlings. Aqueous leachates of R. formosanum flowers, leaves, litter and organic matter inhibited the radicle growth of Ageratum houstonianum, Amaranthus inamoenus, Brassica chinensis, Bidens pilosa, Lactuca sativa and Ocimum basilicum. The leaves aqueous extract contained phytotoxins [p-hydroxybenzoic acid, trans p-coumaric acid, syringic acid, vanillic acid, cis ferulic acid, methyl ferulate, coumarin, protocatechuic acid and (−)-catechin]. These findings and identification of phytotoxins suggests that lack of understory species beneath R. formosanum canopy was due to allelopathic effects.
Allelochemicals, allelopathy, Castanopsis cuspidata var. carlesii, extract, leachate, phenolics, phytotoxin, Rhododendron formosanum
