Allelopathic effects of ginsenoside Rgl on seed germination and seedling growth of Panax ginseng

Soil sickness of ginseng (Panax ginseng C. A. Mey.) has become a major limiting factor in ginseng cultivation. We found that the in rhizosphere soil of 5-year-old ginseng mainly contained ginsenosides viz., Rb1 (2.69 mg L-1), Rg1 (1.94 mg L-1), Re (1.84 mg L-1), Rb2 (1.56 mg L-1) and Rc (1.12 mg L-1 ). High concentration of Rg1 (2.00 mg L-1 ) inhibited the seed germination and seedling growth, but wax stimulatory at low concentrations (0.25 mg L-1). The Rg1 at 1.00 mg.L-1 concentration stimulated the superoxide dismutase, peroxidase and ascorbic peroxidase activities of seedlings but the 2.00 mg L-1 concentration decreased their activities. The Rg1 at low conc (0.25 mg L-1) increased but high concentration (2.00 mg L-1) reduced the contents of gibberellic acid and indole acetic acid. However, the content of abscissic acid was increased by all concentrations of Rg1.