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Publication Type J
Authors Wang, S. M., C. G. Wan, Y. R. Wang, H. Chen, Z. Y. Zhou, H. Fu and R. E. Sosebee
Title The characteristics of Na+, K+ and free proline distribution in several drought-resistant plants of the Alxa Desert, China
Source Journal of Arid Environments
Author Keywords succulent xerophytes xerophytes mesophytes Na (+) K (+) proline Alxa Desert osmotic adjustment drought halophytes x-ray-microanalysis salt tolerance water-stress osmotic adjustment seed-germination agriophyllum-squarrosum atriplex-canescens ion distribution growth sodium
Abstract The distribution characteristics of Na+, K+ and free proline were investigated in succulent xerophytes-Haloxylon ammodendron and Zygophyllum xanthoxylum; xerophytes-Artemisia sphaerocephala and Caragana korshinskii; and mesophytes-Agriophyllum squarrosum and Corispermum mongolicum in the Alxa Desert of China. The results showed that mesophytes and xerophytes were salt excluding species, and the concentrations of Na+ in these species were 1.5% to 3.8% of those in succulent xerophytes. Concentrations of K+ in Agriophyllum squarrosum and Corispermum mongolicum were 1.3-2.7 times those in Artemisia sphaerocephala and Caragana korshinskii. Concentrations of K+ in the stems of Agriophyllum squarrosum and Corispermum mongolicum were 1.8 and 2.2 times those in their roots, respectively, For mesophytes, accumulating large quantities of K+ in their stems may facilitate water movement along a soil-plant gradient. The xerophytes accumulated large quantities of K+ and free proline. Their proline concentrations in the whole plant were 6.0-16.0 times higher than those of mesophytes, and were 1.8-25.0 times higher than those of succulent xerophytes. In Artemisia sphaerocephala, the concentrations of proline increased by 3.1- and 10.5-fold from roots to stems, and from stems to leaves, respectively. A similar trend was observed in Caragana korshinskii. Therefore, accumulating K+ and free proline may play a role in drought adaptation in xerophytes. Succulent xerophytes Haloxylon ammodendron and Zygophyllum xanthoxylum were identified as salt diluting species that absorbed much Na+ by roots, and the Na+ was transported to the leaves and photosynthesizing branches. The succulent xerophytes accumulated larger quantities of Na+ than K+ for osmotic adjustment even at low soil salinities, resulting in the lowest values of selective absorption and selective transport capacities of the root systems. Our data suggest that Na+ accumulation rather than exclusion may be one of the most effective strategies for adaptation of succulent xerophytes to and environments. (C) 2003 Elsevier Science Ltd. All rights reserved.
Author Address Lanzhou Univ, Sch Pastoral Agr Sci & Technol, Lanzhou 730000, Peoples R China. Lanzhou Univ, Gansu Grassland Ecol Res Inst, Lanzhou 730000, Peoples R China. Texas Tech Univ, Dept Range Wildlife & Fisheries Management, Lubbock, TX 79409 USA. Lanzhou Univ, Sch Life Sci, Lanzhou 730000, Gansu, Peoples R China. Wang, SM (reprint author), Lanzhou Univ, Sch Pastoral Agr Sci & Technol, Lanzhou 730000, Peoples R China. smwang@lzu.edu.cn
ISSN 0140-1963
ISBN 0140-1963
29-Character Source Abbreviation J. Arid. Environ.
Publication Date Feb
Year Published 2004
Volume 56
Issue 3
Beginning Page 525-539
Digital Object Identifier (DOI) 10.1016/s0140-1963(03)00063-6
Unique Article Identifier WOS:000187882600009
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