Plant structure adaptations and responses

1. Slide 1 Structure of Plants

2. A. Functions of Roots Slide 2 • Anchor & support plant in the ground • Absorb water & minerals • Hold soil in place Fibrous Roots Root Hairs

3. B. Root Types Slide 3 Tap Root 1. Fibrous Roots:branching roots hold soil in place to prevent soil erosion Ex. Grasses 2. Tap Roots –larger central root reaches deep water sources underground Ex. Trees, Carrots, & Dandelions

4. C. The Structure of a Root Slide 4 Root Hairs • Root Hairs: increase surface area for water & mineral absorption • Meristem: region where new cells are produced • Root Cap: protects tip of growing root Phloem Xylem Meristem Root Cap

5. A. Functions of Stems Slide 5 • Support system for plant body • Transport system carries water & nutrients • Holds leaves & branches upright Looking at the picture to the left: What years had the most rain? What years experienced the worst drought? Each light and dark tree ring equals one year of annual growth. Light rings for fast spring growth, dark for slow summer growth. Smaller rings tell of past droughts that have occurred.

6. A. Functions of Leaves Slide # 6 • Main photosynthetic organ • Broad, flat surface increases surface area for light absorption • Have systems to prevent water loss • Stomata open in day but close at night or when hot to conserve water • waxy cuticle on surface • System of gas exchange • Allow CO2 in and O2 out of leaf Elephant Ear Plant

7. B. Leaf Structures Slide # 7 Leaf Cross-Section Cuticle • Cuticle: waxy layer; covers upper surface • Protects leaf against water loss • Veins: transports water, nutrients and food • Made of xylem and phloem • Mesophyll: contains cells that perform photosynthesis b/c they contain Chloroplasts. Veins Mesophyll Stoma (Opening) 2GuardCells Surround each Stoma Stoma- singular Stomata-plural

8. More Plant Parts… Slide # 8 • Guard cells: • cells that open and close the stoma • Stomata: openings in leaf’s surface; when open: • GAS EXCHANGE: Allows CO2 in & O2 out of leaf • TRANSPIRATION: Allows excess H2O out of leaf Guard Cells Stoma

9. Function of Stomata What goes out? O2 H2O What goes in? CO2 Slide # 9 • What process involves using CO2 andH2O releasing O2 as a waste product? • Photosynthesis • What is the plant using this process to make? • Carbohydrates-glucose • If the plant needs water for photosynthesis, why is water coming out of the stoma? Guard Cells Guard Cells Stoma Closed Stoma Open Stoma

10. Function of Guard Cells Slide # 10 • These stomata (leaf openings) naturally allow water to evaporate out. • Why would the plant close stomata with guard cells? • Prevent excess water loss through transpiration. (conserve water) • So what is the point of having stomata? • Allow gas exchange for photosynthesis Guard Cells Guard Cells Stoma Closed Stoma Open

11. C. Plants find a use for Transpiration Slide # 11 • Transpiration: loss • of excess water from plant leaves • 2. Significance: • Transpiration causes enough pressure to help pull water (& required nutrients) up stem from roots. • As part of the water cycle, trees transpire water back into the atmosphere. • Transpiration provides much of the daily rain in rainforest. B A A average size maple tree can transpire 200 liters of water per hour during the summer. Transpiration is the #1 driving force for pulling water up stems from roots.

12. Stamen Pistil Stigma Anther Style Filament Ovary Petal Ovule Sepal Structure of a Flower Slide # 12 1.Pistil:female reproductive structure • Stigma: sticky tip; traps pollen • Style: slender tube; transports pollen from stigma to ovary • Ovary: contains ovules;ovary develops into fruit • Ovule: contains egg cell which develops into a seed when fertilized

13. Stamen Pistil Stigma Anther Style Filament Ovary Petal Ovule Sepal Structure of a Flower Slide # 13 • Stamen: male reproductive structure • Filament: thin stalk; supports anther • Anther: knob-like structure; produces pollen • Pollen: contains microscopic cells that become sperm cells

14. Stamen Pistil Stigma Anther Style Filament Ovary Petal Ovule Sepal Structure of a Flower Slide # 14 • Sepals: encloses & protects flower before it blooms • Petals: usually colorful & scented; attracts pollinators

15. Cross Pollination Slide # 15 • How does pollination happen? • Pollen from an anther is caught by the stigma, travels through style to the ovules in the ovary. • What is the result of pollination? • A Fruit: An ovary containing seeds.

16. Slide # 16 Chapter 25 Plant Responses and Adaptations

17. Hormone Action on Plants Hormone-producing cells Slide #17 • A. Plant cells can produce hormones: which are chemical messengers that travel throughout the plant causing other cells called target cells to respond. • B. In plants, hormones control: • Plant growth & development • Plant responses to environment Movement of hormone Target cells Cells in one blooming flower signals other blooms using hormones to open.

18. C. Plant cells will send signals to one another to tell them: Slide # 18 • When trees to drop their leaves. • When to start new growth. • When to cause fruit to ripen. • When to cause flowers to bloom. • When to cause seeds to sprout. Leaf Drop Cactus Blooming Fruit Ripening Tree Budding Sprouting Corn Seeds

19. D. Ethylene causes Fruit to Ripen Slide # 19 • Fruit tissues release a small amount of ethlyene • Causes fruits to ripen. • As fruit become ripe, they produce more and more ethlyene, accelerating the ripening process. Ethylene released by apples and tomatoes causes fruit to age quickly.

20. Plant Tropisms Slide # 20 1. Tropism: the way a plant grows in response to stimuli in the environment. • Phototropism: growth response to light -Plants bend towards light • Geotrophism: growth response to gravity -plant roots grow down with gravity, shoots (stems) grow up against gravity and out of the soil. • Thigmotropism: growth response to touch -vines grow up around trees, venus flytrap closeswhen leaves are touched

21. Slide # 21 What type of tropism is shown in these pictures? Phototropism Geotropism Thigmotrophism Thigmotrophism Geotropism Phototropism

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