[Effect of NH4(+) -N/NO3(-)-N ratio in applied supplementary fertilizer on nitrogen metabolism and main chemical composition of Pinellia ternata].
OBJECTIVE
To study the effect of nitrogen forms on nitrogen metabolism and main chemical composition of Pinellia ternate.


METHODS
Through the soilless cultivation experiment and based at the same nitrogen level and different NH4(+) -N/NO3(-) -N ratios, nitrate reductase (NR) activity, glutamine synthetase (GS) activity, the content of nitrate nitrogen and ammonium nitrogen in different parts of P. ternate were determined. The contents of total alkaloid, free total organic acids and guanosine in the tuber were determined. The yield of bulbil and tuber was calculated.


RESULTS
The test results showed that, with the NH4(+) -N/NO3(-) -N ratio increasing, the activity of nitrate reductase decreased, the content of nitrate nitrogen in the leaves, petioles and tuber increasing initially, then decreased, and the content of nitrate nitrogen in the root decreased. Meanwhile, with the NH4(+) -N/NO3(-) -N ratio increasing, the activity of glutamine synthetase in the leaves, petioles and root increased, the activity of glutamine synthetase in the tuber increasing initially, then decreased. The contents of ammonium nitrogen in the leaves, tuber and root increased initially, then decreased, and the contents of ammonium nitrogen in the petioles increased with the NH4(+)(-N/NO3(-)-N ratio increasing. The yield of bulbil and tuber were the highest at the NH4(+)-N/NO3(-) -N ratio of 75: 25. The content of total alkaloid and guanosine in the tuber were the highest at the NH4(+)-N/NO3(-) -N ratio of 0: 100, and the contents were 0.245% and 0.0197% respectively. With the NH4(+)-N/NO3(-) -N ratio of 50: 50, the content of free total organic acids was the highest, it reached 0.7%, however, the content of free total organic acids was the lowest at the NH4(+) -N/NO3(-) -N ratio of 0: 100.


CONCLUSIONS
Nitrogen fertilization significant influences the nitrogen metabolism, the yield and main chemical composition of P. ternate.
Institute of Chinese Medicinal Material, Nanjing Agricultural University, Nanjing 210095, China. jewel129@qq.com
Long-Jiao
LJ
Hu
Kang-Cai
KC
Wang
Can-Wen
CW
Li
D005308:Fertilizers / Q000032:analysis*; D009566:Nitrates / Q000032:analysis*; D009584:Nitrogen / Q000378:metabolism*; D030021:Pinellia / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000032:analysis*
D005308:Fertilizers; D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D009584:Nitrogen