STEM modification and Root modification are two types of plant modifications that are used to achieve different purposes. STEM modification is the process of modifying the stem of a plant to achieve a desired shape or function, such as training a vine to grow up a trellis or creating a graft between two different plants. Root modification, on the other hand, involves modifying the roots of a plant to improve its ability to absorb water and nutrients from the soil, such as by using root cuttings to propagate a plant or applying fertilizers to the roots.