Sometimes called "stock," this is the root system (plant) propagated from seed (seedling) or vegetatively as common in clonal rootstocks on which various cultivars are budded or grafted Many rootstocks are used and possess traits that relate to anchorage, size control, tolerance of light and heavy soils, "wet feet", specific nematodes and other plants and diseases
Plants, in the form of scions, are grafted onto the root system of different, but compatible species for a number of reasons Commonly, the graft is done to furnish a desirable plant with resistance to soilborne disease (that it would normally fall victim to --common with grapes) It may also be done to control the scion's eventual size (see dwarfing rootstock --common with fruit trees)
A root-bearing plant or plant part, generally a stem or root, onto which another plant part (the scion) is grafted Also, the collective roots in a stand, capable of sprouting