| Radix Notoginseng, the root of Panax notoginseng(Buke.)F.H.Chen, which is also called Sanqi in Yunnan and belongs to the Ginseng genus of Araliaceae, is a well-known traditional Chinese medicine(TCM). Sanqi has more than 400 year cultivation history and any wild varieties could be barely found. Wenshan, in southwestern China Yunnan province, is comfirmed as the geo-authentic and largest cultivated area of Sanqi. With the price rising and cultuvation area expanded accordingly. The problems such as over-using nitrogen fertilizers and imbalance nutrition result in plant diseases and pests. Accordingly experiments have been carried out to investigate the effects of nitrogen on growth, yield and quality of Sanqi, aiming at balance fertilization and GAP cultivation development. The main findings showed:(1) Panax notoginseng seedlings got flattened after supplying ammonium and the flattened rate went up with higher nitrogen concentration and longer dealing time, but it did not occur when supplying nitrate nitrogen. Root length and root number got less with more ammonium nitrate as well as the weight per plant. At 10.0 mmol·L-1 nitrogen concentration, plant height and leaf length and the weight per plant supplied ammonium were considerable worse than that of applied nitrate. When increasing ammonium concentration, the GS and GDH activity of P. notoginseng seedling got stronger first then got weaker, which kept going stronger with nitrogen nitrate. At nitrogen concentration of 10.0 mmol·L-1, The GS and GDH activity with ammonium treatment were significant lower than nitrate treatment. The soluable protein and MDA content of both treatments increased, and ammonium treatment reached significant level but nitrate treatment did not. When nitrogen concentration was higher than 5.0 mmol·L-1, the soluable protein and MDA content of P. notoginseng applied ammonium were significant higher than that of applied nitrate. SOD and POD activity increased when applied a low concentration ammonium, but it got converse consequence when applied a high concentration ammonium, which kept increasing when applied nitrate. When nitrogen concentration was higher than 7.5 mmol·L-1, SOD and POD activity with ammonium treatment were significant worse than that of nitrate treatment.(2) The uptake kinetic characteristics of different ammonium and nitrate by P. notoginseng was reached. The Km value of ammonium uptake was higher than that of nitrate uptake by P. notoginseng(Km ammonium<Km nitrate), which indicated that P. notoginseng prefer nitrate. The maximum rate of ammonium uptake by P. notoginseng was larger than that of nitrate uptake and the maximum rate of ammonium was 13.3033 μmol(g·h)-1 and the maximum rate of nitrate was 7.0699μmol(g·h)-1, which indicated that P. notoginseng can uptake much more ammonium.(3) The growth of one-year-old P. notoginseng was inhibited when supplied higher concentration ammonium, and the inhibition became wores with longer time. Increasing nitrate improved the growth of P. notogiseng, but when applied a concentration of 15.0 mmol·L-1 nitrate and long time treatment, the growth of P. notoginseng was also inhibited, but it was still better than ammonium treatment. The root activity of one-year-old P. notoginseng of both treatments increased first, then reduced, which nitrate treatment was better than ammonium treatment. Moderate concentration of ammonium increased GS and GDH activity, but inhibited when applied higher concentration, which were little influenced with different concentration of nitrate and when the concentration was greater than 5.0 mmol·L-1, the GS and GDH activity of nitrate treatment were better than ammonium treatment. The use of nitrogen helpt increase soluable protein. In short time, the soluable protein content of P. notoginseng applied ammonium was more than that of applied nitrate, but as treatment time got longer, it leaded opposite result. The MDA content of P. notoginseng of ammonium treatment kept going up, and was higher than nitrate treatment all along. The MDA content of P. notoginseng of changed little, when applied nitrate in short time, but increased also as treatment time accumulated. As nitrogen concentration increasing, the SOD and POD of ammonium treatment increased first, then reduced, and that of nitrate treatment increased a little.(4) The N content of P. notoginseng increased as nitrogen concentration increasing, and when the concentration was higher than 10.0 mmol·L-1, root N content of ammonium treatment was remarkably greater than nitrate treatment; and As nitrogen concentration increasing, the K content of P. notoginseng applied ammonium was reduced but increased when applied nitrate in short time and the K content of P. notoginseng of nitrate treatment was notable better than that of ammonium treatment. However, as treatment time increased, the K content change trend of P. notoginseng of two treatments were reversed, but there was no considerable difference and also no considerable difference between ammonium and nitrate. Dosage of nitogen showed great effect on P content of P. notoginseng, but there was obvious difference between ammonium and nitrate. Different nitrogen forms had no prominent effect on the content and cumulant of saponins. But Nitrogen dosage had a great effect on monomer saponins of P. notoginseng, and low nitrogen can improve content of saponin and saponins accumulation. Key Words: Panax notoginseng; different nitrogen forms; growth; saponins;... |
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