SILVER THIOSULFATE (STS) is commonly used to block the action of ethylene in plant cell cultures. Ethylene is a hormone that is present in the gaseous state. Ethylene increases during senescence and ripening, and has been shown to increase in plant cell cultures due to wounding, or the presence of auxins. Silver nitrate may be used alone to block the action of ethylene but it is not transported as well as STS thus is seldom used alone.

Prepare a 0.1 M SODIUM THIOSULFATE (STS) stock solution by dissolving 1.58 g of Sodium Thiosulfate into 100 m distilled water.

Prepare a 0.1 M SILVER NITRATE stock solution by dissolving 1.7 g of Silver Nitrate into 100 ml of distilled water. Store the stock solution in the dark until needed to prepare the STS.

The STS solution is prepared with a molar ratio between silver and thiosulfate of 1:4, respectively. Nearly all of the silver present in the solution is in the form of [Ag(S2O3)2]3-, the active complex for ethylene effect inhibition.

Prepare a 0.02 M STS by slowly pouring 20 ml of 0.1 M silver nitrate stock solution into 80 ml of 0.1 M sodium thiosulfate stock solution. The STS can be stored in the refrigerator for up to a month. However, preparation of the STS just prior to use is recommended.
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Many people find it easier to obtain SODIUM THIOSULFATE PENTAHYDRATE than the most called for anhydrous when using the Pentahydrate multiple the weight by 1.56 so the amount would be 1.58 grams multiply x 1.56 its 2.46.48 grams call it 2.4-2.5 and your ok

Everything is exactly the same I have found ST Pentahydrate more gentle not nearly as much of reaction from the plant made me think it was not working worked great !