1. Plant Structure, Growth, & Development

2. The Diversity of Angiosperms • Angiosperms (flowering plants) can be divided into 2 major categories: • Monocots – • have one seed leaf (cotyledon) • Dicots – • have 2 seed leaves (cotyledons)

3. Monocots • Monocots have only 1 cotyledon (seed leaf) • Examples of monocots: • Corn, wheat, lilies, orchids, palms

4. Dicots • Dicots have 2 cotyledons (seed leaves) • Examples of dicots: • Roses, clover, tomatoes, oaks, daisies

5. Woody vs. Herbaceous Plants • Angiosperms can also be subdivided into the groups of woody and herbaceous plants • Woody plants are made of cells with thick cell walls that support the cell body • Examples: trees, shrubs, vines • Herbaceous plants do not produce wood as they grow, and instead have smooth stems • Examples: dandelions, sunflowers

6. Plant Life Spans • Most plants experience indeterminate growth • They continue to grow as long as they live • The lifespan of plants, however, is genetically determined • Annuals – complete their life cycle in 1 year • Examples: marigolds, cucumbers (lots of garden plants) • Biennials - complete their life cycle in 2 years • Year 1: germinate & grow roots • Year 2: grow stems & leaves, produce flowers & seeds • Examples: evening primrose, celery • Perennials – live for more than 2 years • Examples: Maple trees, grasses, palm trees

7. Plant Structure • Plants are made up of a root system and a shoot system

8. The Root System • What do roots do? • Anchor the plant in the soil • Absorb minerals and water • Store food • Types of root systems • Fibrous root system • Found mostly in monocots • Taproot system • Found mostly in dicots

9. How do roots grow? • There are 3 distinct zones in a plant root where different things are taking place • Zone of cell division • Includes the apical meristem • Produces new cells by mitosis • Zone of elongation • Cells get longer • Zone of maturation • The cells differentiate and become specialized • The root is protected by a root cap, which protects the apical meristem as the plant grows down into the soil

10. The Shoot System • The shoot system consists of: • vegetative shoots (which bear leaves) • floral shoots (which bear flowers) • Stems have 3 important functions: • Producing leaves, flowers, branches • Holding leaves up to the sunlight • Transporting substances between roots and leaves

11. How do stems grow? • Primary growth • Increase in length • Occurs by cell divisions in apical meristem (at top of shoot) • Secondary growth • Increase in width • Occurs by cell divisions in the lateral meristems (also known as vascular cambium)

12. Apical Meristems

13. The Shoot System: Leaves • Leaves are attached to stems at nodes • The area between 2 nodes is called an internode

14. The Shoot System: Leaves • Leaves are the primary photosynthetic organs of most vascular plants • Most leaves have a flattened blade and a petiole, which is the stalk that attaches the leaf to the stem

15. Tissue Systems in Plants • All 3 plant organs (root/stem/leaf) have dermal, vascular, and ground tissue systems • Dermal Tissue System • Outer protective covering, similar to our skin  • Protects the plant from water loss and disease • The cuticle is a waxy coating that helps to prevent water loss

16. Tissue Systems in Plants • Vascular Tissue System • Carries out long-distance transport of materials within the plant • Xylem and phloem are examples of vascular tissues • Ground Tissue System • Pith (inside vascular tissue) and cortex (outside vascular tissue) are examples of ground tissue • Includes cells specialized for storage, photosynthesis, and support

17. Flower Structure • Flowers are the reproductive structure of angiosperms • Sepals: • Enclose the bud before it opens • Protect flower while it’s developing • Petals: • Usually brightly colored to attract pollinators

18. Flower Structure • Stamens: • The male portion of a flower • Made up of an anther and a filament • The anther produces haploid pollen grains by meiosis • Most flowers have multiple stamens

19. Flower Structure • Carpels/Pistils: • The female portion of a flower • Stigma: • Sticky – to trap pollen • Style: • Hollow tube which connects stigma and ovary • Ovary: • Produces female gametes (ovules)

20. Monoecious and Dioecious Species of Plants • Monoecious • “one house” • Has both male and female flowers on a single plant • Dioecious • “two houses” • Male and female parts are found on separate plants