*2.1. Seed and Pretreatment*

Freshly matured fruits of *S. aralocaspica* were collected from Fukang, Xinjiang in October 2020. All fruits were manually rubbed to remove the fruit coat. Brown seeds and black seeds were hand-sorted before sterilization to ensure uniformity in type. The seeds were rinsed using running water for 30 s to remove the impurities and then dried naturally in the laboratory. Every group of 50 seeds was packed in a 2 mL Eppendorf tube for further use.

#### *2.2. Preparation of Reagents*

Precisely measured 36 mL 10% NaClO solution and 64 mL sterilized double distilled H2O (ddH2O) were poured into a 150 mL sterile conical flask. Then the mixture was the required solution (100 mL 3.6% NaClO) for this experiment. Accurately weighed 0.1 g HgCl2 reagent powders (Analysis pure) using a calibrated and zeroed electronic balance were poured into a 100 mL sterile beaker. We slowly poured a small amount of sterile ddH2O and stirred with a glass stick until the powder dissolved completely, and then poured the solution into a 100 mL volumetric flask. Next, took a small amount of the new sterile water rinse beaker and glass stirring bar, and combined the rinse solution into the volumetric flask. Repeated the rinsing step 3–4 times (the total volume of the liquid should be less than 100 mL). Finally, added an appropriate amount (depending on the situation) of sterile water to a constant volume of 100 mL. At this point, the 100 mL solution in the 100 mL volumetric flask was the 0.1% HgCl2 solution required for the experiment. MS medium was poured into a disposable sterile bacterial petri dish of 90 mm (d) × 15 mm (h) after autoclave sterilization and solidified into a flat plate at room temperature. The preparation of all the above reagents was completed in an ultra-clean workbench. It is worth noting that mercuric chloride is toxic, so we should be careful when configuring and using it. Besides, adjusting the pH values of MS medium to 5.0, 6.0, 7.0, 8.0, 9.0 respectively was necessary before autoclave sterilization.
