Final answer:
In horticulture and grafting, the primary difference between a rootstock and a scion lies in their functions and characteristics.
Step-by-step explanation:
In horticulture and grafting, the primary difference between a rootstock and a scion lies in their functions and characteristics. A rootstock refers to the plant that provides the root system onto which the scion is grafted. It usually has desirable root characteristics such as disease resistance or environmental adaptation. On the other hand, a scion is the part of the plant that is grafted onto the rootstock. It is selected for its desirable shoot characteristics such as fruit quality or flower color.
For example, in viticulture, the grape variety chosen for its wine production qualities is grafted onto a North American rootstock that provides disease resistance.