Autotoxicity of American ginseng (Panax quinquefoliym L.) was studied in nutrient and soil culture in greenhouse. The autotoxins produced by American ginseng were identified with GC-MS. The most active autotoxins were present in stems, leaves, roots and root exudates. Among these, ether fraction of water extracts and alcohol extracts from either stems, leaves or fibrous roots drastically inhibited the growth of ginseng roots, while, the n-butyl alcohol fraction had little inhibitory effect. When the concentration of water solute autotoxins from stems/leaves or fibrous roots in soil reached 1 g per kg soil, the 4 years old American ginseng plants couldn't grow. At 0.2 g per kg soil concentration, the survival rate of ginseng decreased to 25%. The hydrophobic root secretions were analyzed with GC-MS and 26 compounds were identified, of which more that 64% were fatty acids and the remaining were furantone, sesquiterpenes, alkenes and alcohols.
Allelopathy, autotoxicity, ginseng, Panax quinquefoliym L
