Partitioning of above and below ground costs during phosphate stress in Medicago truncatula |
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Authors: | Lida-Mari Groenewald Rafael J L Morcillo Guy F Midgley Aleysia Kleinert Yves Poirier |
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Institution: | 1. Department of Botany and Zoology, Stellenbosch University, Matieland, South Africa;2. Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, People’s Republic of China;3. Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland |
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Abstract: | Phosphate (P) availability for plant uptake can limit the yield of natural and agricultural systems. Under P limited conditions, the P-requirement of symbiotic nodules of legumes may exacerbate the P stress of host plants. Adaptations to survive under P stress may vary between different functioning tissues. This study investigated the physiological adaptations to P stress in above and below ground organs of nodulated Medicago truncatula Gaertner. Seedlings were inoculated with Sinorhizobium meliloti in quartz sand and fed nutrient solution with either 0.01?mM or 0.5?mM P concentrations. P-stressed nodulated plants showed compromised photosynthetic responses. Alternative growth allocation during stressed conditions was observed between different organs. The concentration of inorganic P, carbon, and nitrogen were lower during stressed conditions. The above ground tissues scavenged P and lowered their dependence on adenosine-triphosphate required for metabolism. Whereas the below ground tissues recycled phosphate from phosphate monoesters in the cell. |
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Keywords: | carbon legumes Medicago truncatula nitrogen fixation organic acids phosphate photosynthesis Sinorhizobium meliloti symbiosis |
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