Plant Parts and Functions Plant parts What do they do? roots hold the plant into the soil. They take in water and minerals to help the plant stay alive. the stem as the elevator that carries water and nutrients from the roots to the other parts of the plant. the flower helps the plant reproduce, making seeds that grow into new plants. leaves take in the air and light to make food that a plant needs to live. Seeds are in the fruit of plants, some fruits are peppers, tomato, apple Leaves are the food making factories of green plants. Veins carry water and nutrients within the leaf. Leaves are the site of the food making process called photosynthesis. In this process, carbon dioxide, water and light energy from the sun, are changed into food (and oxygen for other forms of life). This energy rich sugar is the source of food used by most plants.