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Pak. J. Bot., 48(2): 429-438, 2016. |
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Updated: 01-04-16 | ||||
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MORPHO-PHYSIOLOGICAL RESPONSES OF ALHAGI SPARSIFOLIA SHAP. (LEGUMINOSAE) SEEDLINGS TO PROGRESSIVE DROUGHT STRESS
FANJIANG ZENG1,2,3*, BO ZHANG1,2,3,4, YAN LU1,2,3*, CHANGJUN Li1,2,3,4, BO LIU1,2,3, GUIXIANG AN1,2,3,4 AND XIAOPENG GAO1,2,3, 5
Abstract: Water is a key limiting factor influencing plant growth and development in arid ecosystem. To explore the mechanisms of the desert plant Alhagi sparsifolia seedlings to tolerate drought stress in extreme desert, an experiment was conducted from July to September in 2010 with four water treatments: 100% (W100), 80% (W80), 60% (W60) and 45% (W45) of water holding capacity (WHC). Plant growth, photosynthesis, nutrient content and water use efficiency (WUE) were measured. The results showed that plant growth, branch number, biomass allocation, number of leaves and area per leaf as well as leaf area ratio with drought stress treatments (W80, W60 and W45) decreased than W100 treatment, while root/shoot ratio and specific leaf area increased gradually throughout the experimental duration. Furthermore, photosynthetic pigment content, light-saturated photosynthetic rate, and concentration of carbon and nitrogen in plant significantly decreased with increasing drought stress. The WUE at W100 and W80 treatments increased significantly at the beginning of drought stress treatment and then reduced with stress prolonged. In conclusion, the desert plant A. sparsifolia can tolerate the progressive drought stress due to the strong plasticity of morphological and physiological traits. The critical level of soil WHC to limit the growth and dry mass production of A. sparsifolia seedlings in the southern fringe of the Taklimakan Desert was approximately at 45%.
Key words: Alhagi sparsifolia, Plant growth, Photosynthesis, Nutrient content, Water holding capacity.
1State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences , Urumqi 830011, China 2Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele 848300, Xinjiang, China 3Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China 4University of Chinese Academy of Science, Beijing 100049, China 5Department of Soil Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada *Corresponding author’s email: luyanu@126.com; zengfj@ms.xjb.ac.cn; ph: +86 991 7885439; ph: +86 991 7885442 |
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