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LEAVES 23.4

LEAVES 23.4

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LEAVES 23.4

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  1. LEAVES23.4

  2. Function • Photosynthesis • Transpiration – pulling water up from the roots and out the leaves

  3. Structure • Epidermis • Upper – covered by cuticle • Lower – contains stoma with guard cells

  4. Cont. • Palisade layer – many chloroplasts • Mesophyll – many air spaces • Vascular bundle – “veins”

  5. Vein Epidermis with cuticle Pallisade Layer Mesophyll Stomata

  6. External Structures • Petiole – structure that attached leaf to stem • Blade – thin, flat area of leaf; different sizes, shapes & arrangement • Mid rib – main vein • Leaf margin – edge of leaf

  7. Venation in Monocots and Dicots • Monocots – parallel leaf venation • Dicots – netted venation

  8. Pop Quiz

  9. Flowers, Fruits & SeedsCh. 24

  10. Angiosperms reproduce using flowers.

  11. Flowering Plants have: Dicot Monocot 3 3 4 2 5 4 2 1 5 6 1 8 6 7 Multiples of 3 Multiples of 4 or 5 Flowers 6

  12. Flowers • Composed of modified leaves • Sepals – usually green; enclose bud • Petals– brightly colored; just inside sepals • Stamen – male reproductive organ • Filament - stalk • Anther – produces pollen (male gamete) • Carpel (pistil) – female reproductive organ • Stigma- sticky; pollen attaches here • Style – narrow stalk • Ovary – contains ovules

  13. Stamen Anther Filament male part of flower Parts of a Typical Flower

  14. Stigma Pistil Style Female part of flower (Sounds like “Pigtail”) Ovary Parts of a Typical Flower

  15. Plant Reproduction Plants can reproduce asexually by vegetative propagation. Stems Roots Plantlets Stems, plantlets and roots can become a new plant.

  16. Plant Reproduction Plants can reproduce asexually by plant propagation. Cuttings Grafting & Budding A “cut” from a plant can grow roots when put in soil. Two plants are attached to form one plant.

  17. Angiosperm Life Cycle • Pollination – transfer of pollen from anther to stigma of carpel • Often dependent on pollinators • Pollen grows a tube through which sperm nuclei travel • Fertilization – • sperm nuclei fuse with ovule inside • produce a seed • Ovary ripens into a fruit

  18. Fruits – ripened ovary; type determined by structure of ovary and ovules • Dry • Nuts • Fleshy • Drupes - apple • Pomes - peach • Berries • Hesperidium - orange • Pepo - cucumber • Aggregate - raspberry

  19. Seed Dispersal • Animal • Wind • Water

  20. Seed Germination • Timing controlled by climate (moisture, temperature, etc.) • Endosperm (food source) swells with moisture and cracks open seed coat • Root emerges first • Cotyledons emerge second • Monocot – one seed leaf • Dicot – two seed leaves

  21. Plant Growth • Controlled by hormones (auxins) • Cause “tropisms” • Gravitropism • Thigmotropism • phototropism