Inflorescence development of North American ginseng: abscission zones and ethephon



Fiebig, Andrea E.

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University of Guelph


The development of the North American ginseng (Panax quinquefolium L.) inflorescence, and the effect of the plant growth regulator, ethephon, on structure and function, were examined. Flowering started the last two weeks of June in 1996 and 1997. Constriction zones in distil florets and their pedicels were found in late May and had developed into abscission zones by mid-June. Ethylene at 10 to 100 μl l\sp−1 stimulated abscission zone formation in florets leading to their drop. Varying concentrations (500-4000 mg l\sp−1) of ethephon, an ethylene-releasing compound, were applied to 3-year-old ginseng plants in the field in late June or early July. The highest concentrations had the highest rates of floret removal but caused foliar injury, mostly yellowing. When root weights were analyzed, mid-range concentrations of 1000-1500 mg l\sp−1 ethephon increased root weight, about 25% compared to manual inflorescence removal.



North American ginseng, Panax quinquefolium L., inflorescence, plant growth regulator, ethephon, structure, function