What are the differences between anhydrous and hydrate forms of inorganic salts (AlCl3 , MgSO4 ...) in term of their use for biological applications (ex: in vitro culture) ??
Are you asking how much do you dissolve anhydrates or hydrates in making medium? Just calculate the amount of weight of the contained water molecules in the hydrates in 1 gram molecular weight of a specific hydrate.
Thus, you have to weigh more amount of the hydrates than that of the conyerpart anhydrates in water to make medium.
In some condition, the hydrate salts will lose crystal water and become anhydrous substance, so I think the crystal water may be the key to identify the differences for some biological applications.
yes, we found that anhydrous AlCl3 precipitated in culture medium (for plant embryogenesis) whereas the hexahydrated AlCl3 is completely dissolved as we want.
So we can say that anhydrous salts (like MgSO4) cannot be used as nutrients for in vitro culture but the hydrated salts are suitable for such requirement.
In AlCl3.6H2O, aluminum already reacted with water, so when you add this salt to water, it just dissolves without the liberation of the heat that accompanies the dissolution of AlCl3 itself.
Seemingly you are concerned with the salts aq. solubility ― You may possibly find useful to check my post at the following RG discussion: https://www.researchgate.net/post/How_to_calculate_solubility_of_hydrated_inorganic_salts