Pedosphere 17(5): 595--600, 2007
ISSN 1002-0160/CN 32-1315/P
©2007 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effects of amino acids replacing nitrate on growth, nitrate accumulation, and macroelement concentrations in pak-choi (Brassica chinensis L.) |
WANG Hua-Jing 1,2, WU Liang-Huan2, WANG Min-Yan1, ZHU Yuan-Hong3, TAO Qin-Nan1 and ZHANG Fu-Suo4 |
1 Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310029 (China). E-mail: wanghuajing0631@163.com
2 College of Geography and Resource Sciences, Sichuan Normal University, Chengdu 610066 (China)
3 Department of Crop and Soil Sciences, the Pennsylvania State University (USA)
4 College of Resources and Environment, China Agricultural University, Beijing 100094 (China) |
| ABSTRACT |
| A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen (N), phosphorus (P), and potassium (K) in pak-choi (Brassica chinensis L.) shoots. When 20% of nitrate-N was replaced with arginine (Arg) compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly (P ≤ 0.05), but when 20% of nitrate-N was replaced with alanine (Ala), valine (Val), leucine (Leu), isoleucine (Ile), proline (Pro), phenylalanine (Phe), methionine (Met), aspartic acid (Asp), glutamic acid (Glu), lysine (Lys), glycine (Gly), serine (Ser), threonine (Thr), cysteine (Cys), and tyrosine (Tyr), shoot fresh and dry weights decreased significantly (P ≤ 0.05). After replacing 20% of nitrate-N with asparagine (Ash) and glutamine (Gln), shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine (His), and Arg, significantly reduced (P ≤ 0.05) nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased (P ≤ 0.05). Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N. |
| Key Words: amino acids, growth, N,P,and K, nitrate accumulation, pak-choi |
| Citation: Wang, H. J., Wu, L. H., Wang, M. Y., Zhu, Y. H., Tao, Q. N. and Zhang, F. S. 2007. Effects of amino acids replacing nitrate on growth, nitrate accumulation, and macroelement concentrations in pak-choi (Brassica chinensis L.). Pedosphere. 17(5): 595-600. |
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