Pedosphere 20(4): 536--544, 2010
ISSN 1002-0160/CN 32-1315/P
©2010 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effect of nitrate on root development and nitrogen uptake of Suaeda physophora under NaCl salinity |
YUAN Jun-Feng1,2, FENG Gu3, MA Hai-Yan1,2 and TIAN Chang-Yan1 |
1 Key Laboratory of Oasis Ecology and Desert Environment, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011 (China)
2 Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)
3 College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China) |
| ABSTRACT |
| The effiects of NaCl salinity and NO3- on growth, root morphology, and nitrogen uptake of a halophyte Suaeda physophora were evaluated in a factorial experiment with four concentrations of NaCl (1, 150, 300, and 450 mmol L-1) and three NO3- levels (0.05, 5, and 10 mmol L-1) in solution culture for 30 d. Addition of NO3- at 10 mmol L-1 significantly improved the shoot (P < 0.001) and root (P < 0.001) growth and the promotive effect of NO3- was more pronounced on root dry weight despite the high NaCl concentration in the culture solution, leading to a significant increase in the root:shoot ratio (P < 0.01). Lateral root length, but not primary root length, considerably increased with increasing NaCl salinity and NO3- levels (P < 0.001), implying that Na+ and NO3- in the culture solution simultaneously stimulated lateral root growth. Concentrations of Na+ in plant tissues were also significantly increased by higher NaCl treatments (P < 0.001). At 10 mmol L-1 NO3- , the concentrations of NO3- and total nitrogen and nitrate reductase activities in the roots were remarkably reduced by increasing salinity (P < 0.001), but were unaffected in the shoots. The results indicated that the fine lateral root development and effective nitrogen uptake of the shoots might contribute to high salt tolerance of S. physophora under adequate NO3- supply. |
| Key Words: halophyte, lateral roots, nitrate reductase activity, root morphology |
| Citation: Yuan, J. F., Feng, G., Ma, H. Y. and Tian, C. Y. 2010. Effect of nitrate on root development and nitrogen uptake of Suaeda physophora under NaCl salinity. Pedosphere. 20(4): 536-544. |
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