*2.3. Sterilization and Germination Procedure*

Both types of seeds were first sterilized with 75% ethanol, with a treatment time duration of 30 s, 1 min, 3 min, 5 min, and 8 min. Then seeds were rinsed with sterile distilled water 3 times. Following this, 3.6% NaClO or 0.1% HgCl2 was selected as the secondary sterilizing agent. The soaking time duration of 3.6% NaClO was set to five gradients, including 3, 5, 8, 11, and 15 min and that of 0.1% HgCl2 was also set to five gradients, including 1, 3, 5, 8, and 11 min. Then seeds were cultured on MS mediums with different pH values (Table 1). According to Orthogonal Table L25 (56), 3 columns were used in the test. The sterilization experiment for dimorphic seeds of *S. aralocaspica* was designed. To differentiate the treatments of 3.6% NaClO and 0.1% HgCl2 for different types of seeds, 25 treatments of 3.6% NaClO for brown seeds were named N1–N25 (Table S1), and 25 treatments of 3.6% NaClO for black seeds were named n1–n25 (Table S2). Further, 25 treatments of 0.1% HgCl2 brown seeds were named H1–H25 (Table S3), and the 25 treatments of black seeds treated with 0.1% HgCl2 were named h1–h25 (Table S4). Each experimental group in this study was repeated three times and contained 20 seeds. The above operations were completed in an ultraclean workbench.


**Table 1.** Sterilization programs and parameters of *Suaeda aralocaspica* seeds.

All Petri dishes were incubated in a growth chamber at 25/10 ◦C under a 14 h light/10 h dark photoperiod for 20 days. A seed was considered to be germinated when the radicle length reached 5 mm. Germinated seeds were recorded every day. The final germination percentage (Equation (1)), contamination percentage (Equation (2)) and seedling survival percentage (Equation (3)) were calculated after 20 days of cultivation.


Seedling survival percentage (%) = number of seedlings without contamination and browning/number of tested seeds <sup>×</sup> 100% (3)

#### *2.4. Statistical Analysis*

All data were expressed as mean ± s.e. Arcsine transformation was performed before statistical analysis to meet assumptions. Linear mixed models were used to test the significance of main effects (time duration of ethanol, pH, secondary disinfectant type, time duration of secondary disinfectant, and seeds type) on final germination percentage, contamination percentage, and seedling survival percentage. The statistical analysis was performed using SPSS version 16 (SPSS for Windows, Released 2007, Chicago, IL, USA, SPSS Inc.). One-way ANOVA was used to compare treatments. For comparison, least significance difference test (LSD) (*p* < 0.05) was employed. Independent samples T Test was used to analyze differences between brown and black seeds under different secondary disinfectant treatments.
