• Assertion is true:

Plant families are indeed characterized using both vegetative characters (like leaf, stem, root features) and reproductive characters (like flower, fruit, seed traits).

• Reason is also true:

Genera like Solanum, Petunia, and Datura are correctly placed in the family Solanaceae.

• But the reason is not the correct explanation of the assertion:

It only gives an example of a family, but does not explain why families are characterized using vegetative and reproductive features.