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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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