Figure 1.
Comparison of seed germination rates among Col, Ler and Sha under salt stress treatment.
(A) Plants were grown on MS plate supplied with the indicated concentrations of NaCl (mM). Photos were taken after 5 DAG (Days-After-Germination). Bar = 1 cm. (B) & (C) Germination rates were compared with various concentrations of NaCl. Germination rates were analyzed by counting the number of emergenced radicles after 3 DAG on the indicated concentrations of NaCl in (B) or by counting the number of green cotyledons after 5 DAG in (C). The values indicated means + SEs of four independent experimental repeats (n = 30). (D) & (E) The kinetics of germination time among Col, Ler and Sha were analyzed with the same concentration of NaCl (100 mM). Germination rates were determined by counting the number of emergenced radicles (D) and green cotyledons (E) at the indicated time points. The values indicated means + SEs of four independent experimental repeats (n = 30).
Figure 2.
Adult phenotypes analysis among Col, Ler and Sha after salt stress treatment.
Salt treatments were initiated at 14 DAS (Day-After-Sowing). (A) 2-week-old seedlings of Col, Ler and Sha were treated with indicated concentrations of NaCl for 14 days. Plants were photographed after 2 weeks treatments. (B) Survival rates were calculated from the results of above three independent experiments (n = 20). The values indicated means + SEs. * indicated significant difference with P<0.05 (t-test) in relative to Ler. (C) Relative dry weight comparison after salt treatment. The values indicated means + SEs of four independent experimental repeats (n = 30). * indicated significant difference with P<0.05 (t-test) in relative to Ler. (D) Plants were grown for 2 weeks under normal condition and exposed to different concentrations of NaCl treatments. At 10 days after treatment, aerial plants were harvested for measurement of relative electrolyte leakage. The values indicated means + SEs of four independent experimental repeats (n = 15). * indicated significant difference with P<0.05 (t-test) in relative to Ler.
Figure 3.
Quantitative comparison of superoxide contents and antioxidant enzyme activities (SOD and CAT) among Col, Ler and Sha after salt stress treatment.
Two-week-old plants were started to be treated with the indicated concentrations of NaCl for 10 days before measurement in (B), (C) & (D). The values indicated means + SEs of two independent experimental repeats in (B), (C) & (D) (n = 15). * indicated significant difference with P<0.05 (t-test) in relative to Ler. (A) Visualization of superoxide radical and hydrogen peroxide detected by NBT and DAB staining. Detections have been done on 2-week-old MS-grown plants subjected to subsequent treatment with 200 mM NaCl for the indicated time. Bar = 1 cm. (B) Changes in H2O2 content were analyzed with different salt treatment. (C) Changes in SOD activity were analyzed with different salt treatment. (D) Changes in CAT activity were analyzed with different salt treatment.
Figure 4.
Numbers of gene changed by Sha ecotype effect and salt effect.
Figure 5.
Numbers of overlapping transcripts changed between ecotypes and after salt treatment.
Differentially expressed transcripts were those with P<0.05 and fold change >2. Genes commonly regulated between ecotypes or by salt treatment were highlighted in dotted rectangles and the detailed information of these genes was listed as in Table S1.
Figure 6.
Cluster analyses of transcripts involved in specific pathway.
Red, increase in transcript abundance (up-regulation); green, decrease in transcript abundance (down-regulation); yellow, no change. The color scales were also indicated. Hierarchical cluster analysis was applied for differentially expressed transcripts (P < 0.05 and log 2 fold change > 1 or < −1) with Cluster 3.0 software. The resulting tree figures were displayed using the software package, Java TreeView.
Table 1.
Pathway enrichment analysis showed several pathways were enriched by salinity and ecotype effects.
Table 2.
Stress-related GO term enrichment analysis.
Table 3.
List of genes commonly regulated by salt treatment and in Sha ecotype.
Figure 7.
Model of salt effect and ecotype effects.