Teach your students about the parts of a plant by leading them through a project of putting one together, part by part. Each child gets a paper plate, some yarn, a cupcake liner, a few leaves, a handful of sunflower seeds and a straw. Have them glue the straw to the plate as a flower stem, the cupcake liner as the petals and the yarn as roots. Use real leaves and sunflower seeds to round the flower plant out.
As students learn about the parts that make up a plant, they also learn that each part has a purpose. Use a handout with the parts of a plant identified to illustrate the plant stem, leaves, flowers, seeds and roots. As your students learn to identify each part, discuss with them how each part works with the others to help the plant grow strong and healthy. Discuss how the roots and stem bring water from the ground up through the parts of the plant, how the sun works with the leaves to make food for the plant and that the flowers attract pollinators.
Beans are seeds that grow quickly into large bean plants. Have your kindergarten students fill paper cups with soil and poke a hole with their finger to put a bean into. Set the cups on a sunny window sill and make school time for watering and otherwise caring for the seeds. After a while, they'll have tall bean plants to take home and plant in their yards. As the plants grow, discuss how each part of the plant contributes to the plants health.
Parts of plants often grow into other plants. Bring carrot and pineapple tops, potatoes that have eyes and avocado seeds to class to show students how the process works. Carrot and pineapple tops are the leaves and stems of the plants. When you set them in a saucer filled with pebbles and water, new roots will grow and the plants will continue to grow. Potato eyes are roots. When you plant them in soil, potato plants will grow. Try this with sweet potatoes as well. Suspend an avocado seed, pointed end up, over a glass of water with toothpicks so that your students can see the roots grow down and the stem grow up.