The purpose of the roots in a plant is to anchor the plant in the ground, absorb water and nutrients, and provide support and stability. If a disease harms the roots of a flowering plant, it can hinder the plant's ability to absorb water and nutrients, leading to reduced growth, wilting, and eventually death if the root damage is severe.

Additionally, roots also play a critical role in storing energy reserves for the plant and maintaining its overall health and vitality. They help in the transportation of water and nutrients from the soil to the other parts of the plant. Roots also interact with symbiotic fungi called mycorrhizae, which improve nutrient uptake and enhance the plant's resistance to diseases and environmental stresses. Therefore, if the roots are affected by a disease, it can disrupt these functions and negatively impact the plant's overall growth and survival.