Question

Role of 20% chlorax solution in plant tissue culture

Answer 1

Tween is a mild non-ionic surfactant. Chemically it is a polyethoxylated sorbitan ester. It is highly hydrophilic. In addition to the emulsifying effect, it acts as a wetting agent, dispersant and solubiliser. Therefore it has multiple benefits when used with hypochlorite solution. For example, plant epidermis has trichomes which can trap not only microorganisms but also air, making treatment ineffective. In its role as a wetting agent, it will make the surface of plant wet and repel the air, thus making the treatment effective. This is why Tween 20 is very widely used in wipes, it is non-toxic and inert as it is an ester.

You are quite right, anionic surfactants can also effectively act in a similar way to non-ionic surfactant, but the problem is they denature protein. It also effectively removes oils. So we cannot consider SDS as a mild detergent although it is sometimes used in soaps, and this could be the reason people now use other washing products. It is more widely used in laundry (more harsher application).  I don;t see a big problem using SDS for seeds, but shouldn't be used in surface sterilisation of other tissues. 

So I think by experience biologists have moved away from anionic to nonionic surfactans for surface sterilisation of plant material.