Pedosphere 20(4): 446--455, 2010
ISSN 1002-0160/CN 32-1315/P
©2010 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Root physiological and morphological characteristics of two rice cultivars with different nitrogen-use efficiency |
FAN Jian-Bo1,2,3, ZHANG Ya-Li1,2, D. TURNER4, DUAN Yin-Hua1,2, WANG Dong-Sheng1,2 and SHEN Qi-Rong1,2 |
1 Jiangsu Provincial Key Laboratory for Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing 210095 (China);
2 College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095 (China);
3 Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China);
4 School of Resource Management, The University of Melbourne, Victoria 3010 (Australia) |
| ABSTRACT |
| The variation in nitrogen (N) uptake by rice has been widely studied but differences in rice root morphology that may contribute to this variation are not completely understood. Field and greenhouse experiments were carried out to study N accumulation, root dry weights, total root lengths, root surface areas, and root bleeding rates of two rice cultivars, Elio with low N-use efficiency and Nanguang with high N-use efficiency. Low (1 mmol N L-1) and high (5 mmol N L-1) N applications were established in the greenhouse experiment, and the N rates were 0, 120, and 240 kg ha-1 in the field experiments at Jiangning and Jiangpu farms, Nanjing, China. The results showed that the N accumulation, root dry weight, total root length, and root surface area increased with an increase in N application. At the heading stage, N accumulation in the shoots and roots of Nanguang was greater than that of Elio in the field experiments and that of Elio at 5 mmol N L-1 in the greenhouse experiment. After the heading stage, N accumulation was higher for Nanguang at both 1 and 5 mmol N L-1 in the greenhouse experiment. The total root length and root surface area were significantly different between the two cultivars. Over the range of the fertilizer application rates, the root lengths of Nanguang at Jiangning Farm were 49%-61% greater at booting and 26%-39% greater at heading than those of Elio, and at Jiangpu Farm they were 22%-42% and 26%-38% greater, respectively. Nanguang had a greater root bleeding rate than Elio. It was concluded that the N-use efficiency of the two rice cultivars studied depended to a great extent on the root morphological parameters and root physiological characteristics at different growth stages. |
| Key Words: N accumulation, root bleeding rate, root dry weight, root surface area, total root length |
| Citation: Fan, J. B., Zhang, Y. L., Turner, D., Duan, Y. H., Wang, D. S. and Shen, Q. R. 2010. Root physiological and morphological characteristics of two rice cultivars with different nitrogen-use efficiency. Pedosphere. 20(4): 446-455. |
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