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Silicon enhanced salt tolerance by improving the root water uptake and decreasing the ion toxicity in cucumber.

Wang S, Liu P, Chen D, Yin L, Li H, Deng X - Front Plant Sci (2015)

Bottom Line: The dry weight and shoot/root ratio were reduced by salt stress, but silicon application significantly alleviated these decreases.Moreover, silicon application significantly decreased Na(+) concentration in the leaves while increasing K(+) concentration.Our results indicate that silicon enhances the salt tolerance of cucumber through improving plant water balance by increasing the Lp and reducing Na(+) content by increasing polyamine accumulation.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University Yangling, China ; Institute of Soil and Water Conservation, Chinese Academy of Sciences Yangling, China.

ABSTRACT
Although the effects of silicon application on enhancing plant salt tolerance have been widely investigated, the underlying mechanism has remained unclear. In this study, seedlings of cucumber, a medium silicon accumulator plant, grown in 0.83 mM silicon solution for 2 weeks were exposed to 65 mM NaCl solution for another 1 week. The dry weight and shoot/root ratio were reduced by salt stress, but silicon application significantly alleviated these decreases. The chlorophyll concentration, net photosynthetic rate, transpiration rate and leaf water content were higher in plants treated with silicon than in untreated plants under salt stress conditions. Further investigation showed that salt stress decreased root hydraulic conductance (Lp), but that silicon application moderated this salt-induced decrease in Lp. The higher Lp in silicon-treated plants may account for the superior plant water balance. Moreover, silicon application significantly decreased Na(+) concentration in the leaves while increasing K(+) concentration. Simultaneously, both free and conjugated types of polyamines were maintained at high levels in silicon-treated plants, suggesting that polyamines may be involved in the ion toxicity. Our results indicate that silicon enhances the salt tolerance of cucumber through improving plant water balance by increasing the Lp and reducing Na(+) content by increasing polyamine accumulation.

No MeSH data available.


Related in: MedlinePlus

Effects of silicon (0.83 mM) and salt stress (65 mM) on Na+ (A, leaf; D, stem; G, root), K+ (B, leaf; E, stem; H, root) concentration and K+/Na+ ratio (C, leaf; F, stem; I, root). All parameters were measured after 1.5, 3.5, and 7.5 days of salt treatment. Vertical bars represent the standard deviations (n = 3). Different letters at the same time point represent significant differences (p < 0.05) between the treatments.
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Figure 6: Effects of silicon (0.83 mM) and salt stress (65 mM) on Na+ (A, leaf; D, stem; G, root), K+ (B, leaf; E, stem; H, root) concentration and K+/Na+ ratio (C, leaf; F, stem; I, root). All parameters were measured after 1.5, 3.5, and 7.5 days of salt treatment. Vertical bars represent the standard deviations (n = 3). Different letters at the same time point represent significant differences (p < 0.05) between the treatments.

Mentions: As shown in Figure 6, the Na+ concentration was sharply increased under salt stress in leaves, stems and roots. In stems and roots, silicon application did not decrease the Na+ concentration after 1.5, 3.5, and 7.5 days of salt treatment. In leaves, however, the Na+ concentration was maintained at lower levels in silicon-treated plants than in untreated plants after 3.5 and 7.5 days of salt stress. Salt stress significantly decreased the K+ concentration both with and without silicon. The K+ concentration in stems and roots was not affected by silicon under either normal or salt stress conditions. In leaves, however, the K+ concentration was higher in plants treated with silicon than in untreated plants. Likewise, in stems and roots, the K/Na ratio was not affected by silicon, whereas in leaves the K/Na ratio was maintained at a higher level in silicon-treated plants than in untreated plants after 3.5 and 7.5 days of treatment (Figure 6C).


Silicon enhanced salt tolerance by improving the root water uptake and decreasing the ion toxicity in cucumber.

Wang S, Liu P, Chen D, Yin L, Li H, Deng X - Front Plant Sci (2015)

Effects of silicon (0.83 mM) and salt stress (65 mM) on Na+ (A, leaf; D, stem; G, root), K+ (B, leaf; E, stem; H, root) concentration and K+/Na+ ratio (C, leaf; F, stem; I, root). All parameters were measured after 1.5, 3.5, and 7.5 days of salt treatment. Vertical bars represent the standard deviations (n = 3). Different letters at the same time point represent significant differences (p < 0.05) between the treatments.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585001&req=5

Figure 6: Effects of silicon (0.83 mM) and salt stress (65 mM) on Na+ (A, leaf; D, stem; G, root), K+ (B, leaf; E, stem; H, root) concentration and K+/Na+ ratio (C, leaf; F, stem; I, root). All parameters were measured after 1.5, 3.5, and 7.5 days of salt treatment. Vertical bars represent the standard deviations (n = 3). Different letters at the same time point represent significant differences (p < 0.05) between the treatments.
Mentions: As shown in Figure 6, the Na+ concentration was sharply increased under salt stress in leaves, stems and roots. In stems and roots, silicon application did not decrease the Na+ concentration after 1.5, 3.5, and 7.5 days of salt treatment. In leaves, however, the Na+ concentration was maintained at lower levels in silicon-treated plants than in untreated plants after 3.5 and 7.5 days of salt stress. Salt stress significantly decreased the K+ concentration both with and without silicon. The K+ concentration in stems and roots was not affected by silicon under either normal or salt stress conditions. In leaves, however, the K+ concentration was higher in plants treated with silicon than in untreated plants. Likewise, in stems and roots, the K/Na ratio was not affected by silicon, whereas in leaves the K/Na ratio was maintained at a higher level in silicon-treated plants than in untreated plants after 3.5 and 7.5 days of treatment (Figure 6C).

Bottom Line: The dry weight and shoot/root ratio were reduced by salt stress, but silicon application significantly alleviated these decreases.Moreover, silicon application significantly decreased Na(+) concentration in the leaves while increasing K(+) concentration.Our results indicate that silicon enhances the salt tolerance of cucumber through improving plant water balance by increasing the Lp and reducing Na(+) content by increasing polyamine accumulation.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University Yangling, China ; Institute of Soil and Water Conservation, Chinese Academy of Sciences Yangling, China.

ABSTRACT
Although the effects of silicon application on enhancing plant salt tolerance have been widely investigated, the underlying mechanism has remained unclear. In this study, seedlings of cucumber, a medium silicon accumulator plant, grown in 0.83 mM silicon solution for 2 weeks were exposed to 65 mM NaCl solution for another 1 week. The dry weight and shoot/root ratio were reduced by salt stress, but silicon application significantly alleviated these decreases. The chlorophyll concentration, net photosynthetic rate, transpiration rate and leaf water content were higher in plants treated with silicon than in untreated plants under salt stress conditions. Further investigation showed that salt stress decreased root hydraulic conductance (Lp), but that silicon application moderated this salt-induced decrease in Lp. The higher Lp in silicon-treated plants may account for the superior plant water balance. Moreover, silicon application significantly decreased Na(+) concentration in the leaves while increasing K(+) concentration. Simultaneously, both free and conjugated types of polyamines were maintained at high levels in silicon-treated plants, suggesting that polyamines may be involved in the ion toxicity. Our results indicate that silicon enhances the salt tolerance of cucumber through improving plant water balance by increasing the Lp and reducing Na(+) content by increasing polyamine accumulation.

No MeSH data available.


Related in: MedlinePlus