Effects of NaCl-salinity on amino acid and carbohydrate contents of Phragmites australis |
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| Affiliation: | 1. Humboldt-Universität, Institut für Biologie/AG Ökologie, Unter den Linden 6, D-10099 Berlin, Germany;2. Institut für Pflanzengenetik und Kulturpflanzenforschung, Corrensstr. 3, D-06466 Gatersleben, Germany;1. State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, 72 Wenhua Rd., P.O. Box 417, Shenyang 110016, Liaoning, China;2. School of Natural Resources, University of Missouri, 203m Anheuser-Busch Natural Resources Building, Columbia, MO 65211-7270, USA;3. Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV 895124, USA;1. National Key Laboratory of Human Factors Engineering, China Astronaut Research and Training Center, Beijing 100094, China;2. Beijing Institute of Landscape Architecture, Beijing 100102, China;1. Department of Botany II, Julius-von-Sachs Institute for Biosciences, University of Würzburg, 97082 Würzburg, Germany;2. Centre for Organismal Studies, University of Heidelberg, 69120 Heidelberg, Germany;3. Bio-Protection Research Centre, Lincoln University, Lincoln 7647, New Zealand |
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| Abstract: | The effects of NaCl-salinity on growth, free amino acid and sugar content and composition were assayed in roots, rhizomes and leaves of Phragmites australis (Cav.) Trin. ex Steud. Juvenile plants produced from freshwater clones, were cultured under greenhouse hydroponic conditions for 21 days. Relative growth rates were highest at a salinity level of 0 and 1.5‰, respectively, but decreased significantly at 10‰. All plants cultured at 35‰ salinity died. The osmolality in rhizomes and leaves increased with salinity. The total contents of free amino acids were highest in rhizomes>leaves>roots. In rhizomes, the amino acid content increased significantly up to four-fold from 0 to 10‰ salinity. This increase was caused by up to 200-fold increase of proline and 11-fold increase of glutamine at 10‰, whilst the share of asparagine and glutamate decreased. Leaves showed a similar response to salinity with increasing amino acid contents, and shares of proline and glutamine whereas roots did not react significantly. The contents of sucrose, glucose and fructose were highest in leaves>rhizomes>roots. In rhizomes of all three clones, the sugar contents increased up to 3.5-fold from 1.5 to 10‰ salinity level, but were lower at 1.5‰ versus the control (0‰). Sugar contents were lowest (roots) and highest (leaves) at 1.5‰ salinity. The sugar composition did not vary significantly except for leaves where the fraction of sucrose decreased with increasing salinity level at all three clones from 89.1 to 61.7% of total dissolved sugar (pooled data). The importance of free amino acids and sugars as osmolytes was similar in rhizomes and leaves (13–15% of total osmolality at 10‰). In rhizomes, free amino acids were more important as osmolyte than sugars, while the opposite was true for leaves. Proline contributed up to 2.7% to total osmolality. It is hypothesised that a strong proline accumulation indicates the exceeding of a critical salinity level. |
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