Chin J Plant Ecol ›› 2006, Vol. 30 ›› Issue (1): 140-146.DOI: 10.17521/cjpe.2006.0020

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HE Heng-Bin1, JIA Kun-Feng2, JIA Gui-Xia1,*(), DING Qiong3   

  1. 1 Laboratory of Genetics and Breeding of Trees and Flowers, National Engineering Research Center for flowers, Beijing Forestry University, Beijing 100083, China
    2 Forestry Bureau of Wulatehouqi County, Wulatehouqi, Inner Mongolia 015500, China
    3 Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
  • Received:2005-06-01 Accepted:2005-10-17 Online:2006-06-01 Published:2006-01-30
  • Contact: JIA Gui-Xia


Ammopiptanthus mongolicus is an endangered evergreen broad-leaf species in the northwest desert zone of China. Shapotou, Alashanzuoqi, Dengkou and Wulatehouqi were defined as research regions based on soil, water and other ecological factors. Nodules of A. mongolicus were collected during the last twenty-days of April, which was the flowering period of the host, and their characteristics were studied. The resistance of rhizobia isolated from A. mongolicus also was studied in relation to environmental factors of the distribution areas. Seventeen rhizobia strains were isolated from A. mongolicus. It was found that nodules had various attachment modes, sizes, shapes and colors, which were related to differences of their environment, of which water may be the most important determinant. Several biochemical characteristics were determined, including resistance to salt, acid-alkali, temperature variation and intrinsic antibiotics. The results indicated that 64.7% strains could tolerate NaCl stress at 3% concentration, 94.1% strains could grow at a range of pH from 5-11, and all strains could grow after being exposed to 60 ℃ for 10 min. Differences in resistance to different intrinsic antibiotics existed among strain ZW4, and WH41 had high a resistance to different intrinsic antibiotics. Rhizobia strains from Dengkou had higher resistance to acid-alkali conditions and temperature. These results indicated that rhizobia strains isolated from A. mongolicus were highly resistant to stresses. However, there were differences among strains in their resistance to stresses, which might be related to adaptations of rhizobia to the diverse landscapes in different regions. Resistances of rhizobia strains isolated from accompanying plants, for example, Caragana corshinskii, Caragana intermedia and Oxytropis aciphylla, also were studied, and the results indicated that they also were highly resistant to stresses similar to the rhizobia strains isolated from A. mongolicus. These results indicated that the symbiosis between rhizobia and legumes was influenced by their environment. The high resistance of A. mongolicus may be related to the high resistance of its rhizobia, and that the symbiotic relation was beneficial to the development and maintenance of its community in diverse landscapes.

Key words: Ammopiptanthus mongolicus, Rhizobia, Resistance, Eco-environment, High resistance