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Plants

Plants. Chapters 22, 23, and 24 . Introduction to Plants . Characteristics Plants are multicellular eukaryotes that have cell walls made of cellulose . Carry out photosynthesis using the green pigments chlorophyll a and b found in chloroplasts

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Plants

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  1. Plants Chapters 22, 23, and 24

  2. Introduction to Plants • Characteristics • Plants are multicellular eukaryotesthat have cell walls made of cellulose. • Carry out photosynthesis using the green pigments chlorophyll a and b found in chloroplasts • Most are autotrophs, few are parasites or saprobes • Non-motile (fixed to one spot) • Responds to the environment and grows through the use of hormones

  3. Transport in Plants The “circulatory system” of the plant world

  4. Plant Tissue Systems • Vascular Tissue • Xylem – water-conducting tissue • Phloem– food-conducting tissue • Xylem and phloem work together to move fluids throughout the plant body, even against gravity • Arranged in vascular bundles

  5. Functions of Plant Organs • Flowers- Brightly colored to attract pollinators; seed bearing structures; helps reproduction • Roots- Movement into vascular cylinder; absorbs water and nutrients; anchors plants • Stems- Transport substances between roots and leaves; holds leaves up to sun • Leaves- Photosynthesis; gas exchange

  6. Gas Exchange – CO2 in and O2 out Stomata- small pores on the underside of the leaf that regulates gas exchange with help from guard cells - stomata open to let enough gas in, but not enough to lose too much water -stomata open – during the day to complete photosynthesis (except during warm/dry weather) - stomata close – night to conserve water and during warm/dry weather

  7. Transport in Plants • Transpiration – evaporation from the leaves forces water to be drawn up from the roots, stems and out through the leaves • Nutrient Transport – pushes through phloem • movement from plant source (where sugars are made) to sink (where sugars are stored) • Nutrients moving causes a change in the concentration, thus moving nutrients

  8. Transport in Plants Water – root pressure, capillary action, and transpiration move water through the xylem Capillary action – -cohesion – water attracted to other water molecules -adhesion – water molecules form H+ bonds with other substances -capillary action – water is transported up a thin tube. The thinner the tube, the higher water will rise

  9. Response in Plants What do plants do since they cannot move?

  10. Tropisms • Tropism- The response of plants to external stimuli. • Geotropism- Growth in plants in response to gravity. • Phototropism- Movement of plants towards or away from light. • Hydrotropism- Movement of plants towards or away from water. • Thigmotropism- Directional response of a plant organ to touch or contact with a solid object.

  11. http://www.youtube.com/watch?v=1ZuZ_1cQnv4 • http://www.youtube.com/watch?v=zctM_TWg5Ik • http://www.youtube.com/watch?v=Ze8NV7cvW8k

  12. Plant Reproduction The goal of all living organisms!

  13. Pollen cone (male cone) male gametophyte (pollen grains) smaller Seed cone (female cone) female gametophyte larger Gymnosperms – Cones

  14. Structure of Flowers: Sepals Petals Stamen- Male Filament Anther Carpel/Pistil Female Stigma Style Ovary Ovule Angiosperms - Flowers

  15. Seeds Pollination – transfer of pollen from male structures to female structures Pollen Dispersal- Gymnosperms- wind Angiosperms- wind/animals • Seed and Fruit Development • As seeds mature the ovary wall begins to thicken, forming a ________ • Seed Dispersal • Animals • Wind and water

  16. Development Seed Dormancy – embryo alive but not growing - Influenced by environmental factors - Plants want to come out of dormancy when ideal conditions are available Seed Germination – early growth stage of a plant embryo

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