氮素形态对黄瓜幼苗生长及氮代谢酶活性影响

用营养液培养的方法,研究了同一氮素水平不同氮素形态比例对黄瓜幼苗生长及氮代谢关键酶：硝酸还原酶（NR）、谷氨酰胺合成酶（GS）活性的影响。结果表明：单独供给硝态氮（NO3^--N）比单独供给铵态氮（NH4^＋-N）更有利于黄瓜幼苗的生长;当NO3^--N∶NH4^＋-N为75∶25时,主根长度、根总表面积、根总体积、株高、茎粗、地上部干重的值最大。NR活性随NO3^--N比例的增加而增加,GS活性在NH4^＋-N比NO3^--N少时,随NH4^＋-N的比例增加而增大,当NO3^--N∶NH4^＋-N为50∶50时活性最大,当NH4^＋-N大于NO3^--N时活性下降。表明NO3^--N∶NH4^＋-N为75∶25时对黄瓜幼苗最适宜。

Effects of Different Ratios of Nitrogen Forms on Enzyme Activities Related to Nitrogen Metabolism and Growth of Cucumber Seedlings

Abstract: Our study focused on different shape ratio of Nitrogen with the same quantity influenced the cucumber seedlings growth and influenced the key nitrogen metabolism enzyme: nitrate reductase (NR), glutamine synthetase (GS). Results showed, compared to single ammonium nitrogen (NH4+-N) supply, single nitrate nitrogen (NO3--N) supply is better for cucumber seedlings growth. When NO3--N: NH4+-N ratio at 75:25, the length of axial root, total surface area of root, total volume of root, height of strain, stem thickness, dry weight of earth proportion was the highest. NR activity was increased along with NO3--N increasing. When NH4+-N supply was less than NO3--N, GS activity was increased along with NO3--N increasing. When NH4+-N supply was equal to NO3--N, GS activity arrived peak. When NH4+-N supply was more than NO3--N, GS activity descent. In conclusion, NO3--N: NH4+-N ratio at 75:25 was the best proportion for cucumber seedlings growth.