The absorption distribution and utilization of N in different nitrogen forms by american ginsengs

NH4+ and NO3- uptake by 2,3,4-year old Panax quinquefolium and their distribution in the plants were studied with 15N tracer in both soil and water cultures. The results showed that P. quinquefolium can absorb both NH4+ and NO3- from sprouting stage to leaf expansion stage, but the absorbing capacity for NH4+ was twice as that for NO3-, and during this period more fertilizer was distributed in stem and leaves than in roots. During the stage of root growth, however, the plants absorbed the both forms of fertilizer well, and more fertilizer was distributed in root than in stem and leaves. Of the total nitrogen content absorbed by P. quinquefolium cultured in soil, more than 80% was from soil, about 5% was from fertilizer, and the rest was from original root. It is concluded that improving fertility of soil and culturing strong root are keys to improve yield and quality of P. quinquefolium