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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 polyamines (PAs) concentrations (putrescine, Put; spermidine, Spd; and spermine, Spm; (A) Free Put; (B) Free Spd; (C) Free Spm; (D) Total free polyamines; (E) Conjugated Put; (F) Conjugated Spd; (G) Conjugated Spm; (H) Total conjugated polyamines). Root tips (1 cm) were used for measurement. 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 results of the treatments. Sharing the same letter indicates no significant difference.
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Figure 7: Effects of silicon (0.83 mM) and salt stress (65 mM) on polyamines (PAs) concentrations (putrescine, Put; spermidine, Spd; and spermine, Spm; (A) Free Put; (B) Free Spd; (C) Free Spm; (D) Total free polyamines; (E) Conjugated Put; (F) Conjugated Spd; (G) Conjugated Spm; (H) Total conjugated polyamines). Root tips (1 cm) were used for measurement. 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 results of the treatments. Sharing the same letter indicates no significant difference.

Mentions: In roots, the total free polyamines were not affected by silicon application under normal conditions. Salt stress decreased the total free polyamines after 3.5 and 7.5 days, but silicon application moderated this salt-induced decrease in polyamine levels. Three free polyamines were considered separately. Salt stress decreased the putrescine concentration, while silicon application reversed this decrease. Salt stress also decreased the spermidine concentration, while silicon application alleviated this decrease only after 7.5 days of treatment. Salt stress also decreased the free spermine concentration, but silicon did not affect this decrease under either normal or salt stress conditions. As for conjugated-type polyamines, silicon application enhanced the putrescine and spermine levels, but caused a decrease in spermidine concentration (Figure 7).


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 polyamines (PAs) concentrations (putrescine, Put; spermidine, Spd; and spermine, Spm; (A) Free Put; (B) Free Spd; (C) Free Spm; (D) Total free polyamines; (E) Conjugated Put; (F) Conjugated Spd; (G) Conjugated Spm; (H) Total conjugated polyamines). Root tips (1 cm) were used for measurement. 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 results of the treatments. Sharing the same letter indicates no significant difference.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 7: Effects of silicon (0.83 mM) and salt stress (65 mM) on polyamines (PAs) concentrations (putrescine, Put; spermidine, Spd; and spermine, Spm; (A) Free Put; (B) Free Spd; (C) Free Spm; (D) Total free polyamines; (E) Conjugated Put; (F) Conjugated Spd; (G) Conjugated Spm; (H) Total conjugated polyamines). Root tips (1 cm) were used for measurement. 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 results of the treatments. Sharing the same letter indicates no significant difference.
Mentions: In roots, the total free polyamines were not affected by silicon application under normal conditions. Salt stress decreased the total free polyamines after 3.5 and 7.5 days, but silicon application moderated this salt-induced decrease in polyamine levels. Three free polyamines were considered separately. Salt stress decreased the putrescine concentration, while silicon application reversed this decrease. Salt stress also decreased the spermidine concentration, while silicon application alleviated this decrease only after 7.5 days of treatment. Salt stress also decreased the free spermine concentration, but silicon did not affect this decrease under either normal or salt stress conditions. As for conjugated-type polyamines, silicon application enhanced the putrescine and spermine levels, but caused a decrease in spermidine concentration (Figure 7).

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