Below are ideas for extending this topic beyond the activity & exploration you just completed.
These online books are free for educators registered on Epic!:
Plants Are Alive by Molly Aloian explores how the parts of a plant, such as roots, stems, and flowers, help a plant survive.
Max Plants a Seed by Kerry Dinmont is a picture book that shows what happens when Max plants a sunflower seed.
This timelapse video of a seed germinating would make a great opportunity for discussion:
For more on how to lead great science discussions, see this list of talk moves from The Inquiry Project.