It is critical to establish a standard cultivation procedure forhedysari radix, and explore new ways of using less fertilizer for high yields of Chinese herbal crops, and provide theoretical basis for the application of palygorskite in cultivating Chinese traditional medicine. To that end, a field experiment was conducted to study the dynamics, absorption and distribution of nitrogen and polysaccharides in hedysari radix. The effects of palygorskite application rates of 750 kghm-2 (PI), 1 500 kg-hm2 (P2) and 2 250 kg-hm-2 (P3) with NPK fertilizer on nitrogen absorption and polysaccharide accumulation in hedysari radix were also analyzed. The results showed that the critical period of nitrogen nutrition in aboveground part of hedysari radix was late June to late July. However, increased nitrogen requirement by the root system of hedysari radix was noted in late August. From late September to late October, nitrogen transfer occurred from aboveground part to belowground tissues. Also from late June to late August, the content of polysaccharides sharply increased in the root system of hedysari radix plant. Compared with only NPK application, combined application of palygorskite and NPK fertilizer increased N content at the late growth stage of the plant. It also increased N content in roots and active aboveground growth tissues. Compared with NPK treatment, NPK+P3, NPK+P2 and NPK+P1 treatments increased hedysari radix N accumulation at harvest by 45.22%, 29.45% and 20.06%, respectively. N accumulation in the aboveground part of the plant under NPK+P3 treatment increased by 71.99%, compared with NPK treatment. N accumulation in the root system under NPK+P3 and NPK+P2 treatments increased by 38.72% and 26.07%, respectively. NPK+P3 treatment promoted N accumulation and prolonged the period of N accumulation in the aboveground part of hedysari radix at the early growth stage. It also delayed N de-accumulationin the aboveground part of the plant at the late growth stage. NPK+P3 and NPK+P2 treatments enhanced the rate of N accumulation in roots. They also increased single plant root N accumulation over NPK treatment. The content of polysaccharides under NPK+P1, NPK+P2 and NPK+P3 treatments increased by 50.74%, 62.95% and 40.63%, respectively, over NPK treatment. The combined application of palygorskite and NPK prolonged accumulation time of polysaccharides in hedysari radix. While it delayed polysaccha-ride de-accumulation in roots, and improved overall polysaccharidc yield of the plant. The comprehensive performance of N absorbing capacity under combined application of palygorskite and NPK was in the following order NPK+P1 (high rate) > NPK+P2 (medium rate) > NPK+P3 (low rate). The further studies on this observed correlation between palygorskite and polysaccharide output were recommended.%田间试验研究了红芪氮素吸收分配动态和多糖含量的变化规律,以及增施 3 种水平坡缕石(P1,750kg·hm-2; P2,1 500 kg·hm-2; P3,2 250 kg·hm-2)对红芪吸氮和多糖积累的影响.结果表明:6月下旬至7月下旬是红芪茎叶对氮的营养临界期,而红芪根在8月下旬以后对氮的需求量增大,9月下旬至10月下旬为氮素从茎叶向根系转移的时期,6月下旬至8月下旬是红芪多糖含量的快速积累期.在红芪收获期,NPK+P3、NPK+P2和NPK+P1处理的全株氮素积累量分别比NPK对照提高45.22%、29.45%和20.06%,NPK+P3处理的茎叶氮素积累量比NPK对照提高71.99%,NPK+P3、NPK+P2处理的根氮素积累量分别比NPK对照提高38.72%和26.07%;NPK+P1、NPK+P2和NPK+P3处理的多糖含量分别较NPK对照提高50.74%、62.95%和40.63%.坡缕石配施用量对红芪吸氮的促进效果综合表现为高用量＞中用量＞低用量,但其配施用量与多糖产量的关系还需进一步研究确定.
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