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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 the fresh weight (A) and root/shoot ratio (B) of cucumber seedlings. 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 1: Effects of silicon (0.83 mM) and salt stress (65 mM) on the fresh weight (A) and root/shoot ratio (B) of cucumber seedlings. 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 1A, no effect of silicon on biomass was observed under control conditions. Salt stress significantly decreased plant growth after 3.5 and 7.5 days of treatment. Silicon application clearly alleviated the salt-induced inhibition of growth. After 7.5 days salt treatment, the FW of silicon-treated plants was 37% higher than that of untreated plants. In addition, the root/shoot ratio was decreased by salt stress after 7.5 days of treatment, and silicon application moderated this decrease (Figure 1B). Chlorophyll concentration was not affected by salt or silicon after 1.5 and 3.5 days of salt treatment. After 7.5 days of salt treatment, however, chlorophyll concentration was significantly decreased; silicon application alleviated this salt-induced decrease in chlorophyll concentration. Similarly, the net photosynthetic rate was decreased after 7.5 days of salt treatment, and silicon application significantly alleviated this decrease (Figure 2). These results show that silicon application enhanced cucumber salt tolerance.


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 the fresh weight (A) and root/shoot ratio (B) of cucumber seedlings. 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 1: Effects of silicon (0.83 mM) and salt stress (65 mM) on the fresh weight (A) and root/shoot ratio (B) of cucumber seedlings. 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 1A, no effect of silicon on biomass was observed under control conditions. Salt stress significantly decreased plant growth after 3.5 and 7.5 days of treatment. Silicon application clearly alleviated the salt-induced inhibition of growth. After 7.5 days salt treatment, the FW of silicon-treated plants was 37% higher than that of untreated plants. In addition, the root/shoot ratio was decreased by salt stress after 7.5 days of treatment, and silicon application moderated this decrease (Figure 1B). Chlorophyll concentration was not affected by salt or silicon after 1.5 and 3.5 days of salt treatment. After 7.5 days of salt treatment, however, chlorophyll concentration was significantly decreased; silicon application alleviated this salt-induced decrease in chlorophyll concentration. Similarly, the net photosynthetic rate was decreased after 7.5 days of salt treatment, and silicon application significantly alleviated this decrease (Figure 2). These results show that silicon application enhanced cucumber salt tolerance.

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