First Flowering Plants

1. First Flowering Plants • Angiosperm: flowering plants • vascular • heterospory • male vs. female gametophytes • flower • specialized structure for sexual reproduction • seeds within fruit • pollen • life cycle dominated by sporophyte stage • trees & bushes you are familiar with are diploid • reduced (microscopic) gametophyte

2. Angiosperm: flowering plants

3. PLANTS! Basic Structure & Tissues (Ch. 29, Lecture 9)

4. General Plant Structure Apical Meristems Lateral meristem

5. Apical Meristems • Apical meristem – localized region of cell division at the plant shoot & root tip • Cells formed in the apical meristems differentiate into the plants various epidermal tissue cells.

6. Lateral Meristems • Lateral meristems – add girth and protection to the stem of an older plant • Vascular cambium – produces secondary vascular tissue • Cork cambium – produces protective covering (periderm) that replaces epidermis

7. Land Plant Tissues • Simple Tissues/Ground Tissue • Parenchyma – soft, primary growth tissue in stems & leaves • Primary component of ground tissue) • Collenchyma – support for soft tissues; ribs in leaf stalks • Sclerenchyma – fibrous protective tissue (fortified with lignin)

8. Simple Tissues Fibrous support structures Sclereid cell fortified with lignin

9. Land Plant Tissues • Complex Tissues/Vascular Tissues • Xylem – transport of water & ions; mechanical support • Phloem – transports sugars and solutes

10. Complex Tissues Live Phloem sieve tubes for sugar & solute transport Xylem “pipelines” (water transport)

11. Land Plant Tissues • Dermal Tissues • Epidermis – unspecialized plant surface cells • Stomata – gaps in epidermis to allow material passage • Cuticle – waxy surface coating to prevent water loss • Periderm – protective outer covering, replaces epidermis • Forms bark in trees

12. Dermal Tissues Epidermal cells secrete waxy cutin to make cuticle Photosynthesis is happening in the parenchyma cells!

13. Monocots & Dicots Palms, lilies, bamboo etc… Maple tree, peas, cacti etc…

14. Shoots & Leaves • Shoot – above ground plant parts • Bud – gives rise to leaves & flowers • Vascular bundles – organization of xylem & phloem • Cortex – outer stem layer, coats vascular bundles • Pith – center of stem

15. Shoots

16. Monocot Scattered vascular bundles throughout stem Dicot Rings of vascular bundles around ground tissue Monocot vs. Dicot Shoots Epidermis Epidermis Pith

17. Shoots & Leaves • Leaf – metabolic factory for photosynthesis • Epidermis – coats leaf; openings called stomata • Mesophyll – photosynthetic tissue made of parenchyma tissue • Veins – leaf vascular bundles

18. Leaves

19. Roots • Root Tissues • Stele~ the vascular bundle where both xylem and phloem develop • Pith~ central core of stele in monocot; parenchyma cells • Cortex~ region of the root between the stele and epidermis (innermost layer: endodermis) • Primary Root – first root to emerge from seed • Lateral Root – outer layer/branches; may become meristematic • Taproot System – primary “central” root & laterals • Dandelions, carrots, oak trees, etc… • Fibrous Root System – multiple lateral roots • Grasses

20. Primary Root Structure Lateral root

21. Lateral Root Formation

22. Taproot vs. Fibrous Root