Plant Structures and Functions

1. Plant Structures and Functions Mr. Rodriguez Mena

2. Structure of Seed Plants • The three principal organs of seed plants are roots, stem, and leaves. • Roots: For absorption of water and nutrients (also anchoring the plant to the floor) • Stems: Supports the plant body and transport the nutrients. • Leaves: Main organ use in photosynthesis

3. Tissue System • Plants consist of four tissues: • Meristematic tissue: is the only plant tissue that produces new cells by mitosis. • Dermal tissue: outer most covering layer of the plant (contains epidermal cells, a waxy layer named cuticle and trichomes) • Vascular tissue: contains several different cell types (the Xylem and the Phloem) • Ground tissue: contains different cell depending on the plant: parenchyma, collenchyma and sclerenchyma.

4. Body Plan of Plants

5. Plant Structure

6. Roots • The two main types of roots are taproots, which are found mainly in dicots, and fibrous roots, which are found mainly in monocots.

7. Root Structure and Growth • A mature root has an outside layer, the epidermis, and central cylinder of vascular tissue. Between these two tissues lies a large area of ground tissue.

8. Root functions • Roots anchor a plant in the ground and absorb water and dissolved nutrients from the soil.

9. Stems • In general, stems have three important functions: They produce leaves, branches and flowers; they hold leaves up in the sunlight: and they transport substances between roots and leaves.

10. Monocot and Dicot Stem • In monocots, vascular bundles are scattered throughout the stem. In dicots and most gymnosperms, vascular bundles are arranged in a cylinder.

11. Primary and Secondary growth • Primary growth of stems is produced by cell divisions in the apical meristem. It takes place in all seed plants. • In conifers and dicots, secondary growth takes place in lateral Meristematic tissues called the vascular cambium (increases thickness) and cork cambium (produces the outer covering).

12. Leaf Structure • The structure of a leaf is optimized for absorbing light and carrying out photosynthesis.

13. Leaf Functions • Plants keep their stomata open just enough to allow photosynthesis to take place, but not so much that they lose an excessive amount of water

14. Water Transport • The combination of root pressure, capillary action, and transpiration provides enough force to move water through the xylem tissue of even the largest plants.

15. Nutrient Transport • When nutrients are pumped into or removed from the phloem system, the change in concentration causes a movement of fluid in that same direction. As a result, phloem is able to move nutrients in either direction to meet the nutritional needs of the plant.

16. Questions???

18. Quiz!!! • Date, Name and Period • Meristematic tissue is the only plant tissue that produces new cells by mitosis. • Dermal tissue contains several different cell types (the Xylem and the Phloem) • The Xylem is use for nutrient absorption and the Phloem for fluids. • Stems supports the plant body and transport the nutrients. • What is capillary action?