Differences in physiological responses to NaCl between salt-tolerant Sesbania rostrata Brem. & Oberm. and non-tolerant Phaseolus vulgaris L. |
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| Authors: | JARUNEE JUNGKLANG KENJI USUI HIROSHI MATSUMOTO |
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| Institution: | Doctoral Program in Agricultural Sciences;and Institute of Applied Biochemistry, University of Tsukuba, Tsukuba, Ibaraki, Japan |
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| Abstract: | Sesbania rostrata ( S. rostrata) Brem. & Oberm., a member of the Fabaceae family, has been used as a promising halophytic plant to ameliorate soil salinity in north-east Thailand. To obtain information regarding the mechanism of salt tolerance, the physiological responses of S. rostrata to NaCl was compared with those of the salt-susceptible species, kidney bean ( Phaseolus vulgaris L. cv. Meal). Seedlings were grown hydroponically with 0, 50, 100 and 150 m m NaCl for 10 days and their effects on growth, chlorophyll content, fluorescence yield ( F v/ F m), inorganic elements and amino acid content were determined. The results showed that tolerance to NaCl was clearly different between the two plants. At the highest concentration (150 m m ), the dry weight of S. rostrata was more than 50% greater than the control, whereas the kidney bean could not survive. Chlorophyll a content drastically reduced only in the kidney bean. The F v/ F m of S. rostrata did not change with increasing concentrations of NaCl, but that of kidney bean decreased. Greater percentages (≥80%) of absorbed Na+ and Cl– were translocated and accumulated in the shoots of S. rostrata , but remained largely in the roots of kidney bean. The enhancement of contents of amino acids, including proline, with increasing NaCl was observed in both species. These results strongly suggest that the salt tolerance of S. rostrata is associated with the ability of the plant to translocate and sequester Na+ and Cl– in the shoot cells. |
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| Keywords: | amino acid kidney bean (Phaseolus vulgaris L cv Meal ) mechanism of salt tolerance NaCl proline Sesbania rostrata |
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