Slide 1 Structure of Plants Slide 2 1

Slide 1 Structure of Plants

Slide 2 1. 2. 3. A. Functions of Roots Anchor & support plant in the ground Absorb water & minerals Hold soil in place Root Hairs Fibrous Roots

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

Slide 4 C. The Structure of a Root Hairs Phloem Xylem Meristem Root Cap 1. Root Hairs: increase surface area for water & mineral absorption 2. Meristem: region where new cells are produced 3. Root Cap: protects tip of growing root

Slide 5 A. Functions of Stems 1. Support system for plant body 2. Transport system carries water & nutrients 3. Holds leaves & branches upright Looking at the Each light and dark picture to the left: tree ring equals one year of annual growth. What years had Light rings for fast the most rain? spring growth, dark for slow summer growth. What years Smaller rings tell of experienced the past droughts that have occurred. worst drought?

Slide # 6 A. Functions of Leaves 1. Main photosynthetic organ 2. Broad, flat surface increases surface area for light absorption 3. Have systems to prevent water loss • Stomata open in day but close at night or when hot to conserve water • waxy cuticle on surface 4. System of gas exchange • Allow CO 2 in and O 2 out of leaf Elephant Ear Plant

Slide # 7 B. Leaf Structures Leaf Cross-Section 1. Cuticle: waxy layer; covers upper surface Cuticle Mesophyll • Protects leaf against water loss 2. Veins: transports water, nutrients and food • Made of xylem and phloem 3. Mesophyll: contains cells that perform photosynthesis b/c they contain Chloroplasts. Veins Stoma (Opening) 2 Guard Cells Surround each Stoma- singular Stomata-plural

Slide # 8 More Plant Parts… 4. Guard cells: • cells that open and close the stoma 5. Stomata: openings in leaf’s surface; when open: • • GAS EXCHANGE: Allows CO 2 in & O 2 out of leaf TRANSPIRATION: Allows excess H 2 O out of leaf Guard Cells Stoma

Slide # 9 What goes O 2 out? Function of Stomata • What process involves Guard Cells using CO 2 and H 2 O releasing H 2 O O 2 as a waste product? • Photosynthesis What goes in? Stoma CO 2 Stoma Open • What is the plant using this process to make? Stoma Closed • Carbohydrates-glucose • If the plant needs water for photosynthesis, why is water coming out of the stoma?

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

Slide # 11 C. Plants find a use for Transpiration 1. Transpiration: loss 2. of excess water from plant leaves 2. Significance: a. Transpiration causes enough pressure to help pull water (& required nutrients) up stem from roots. b. As part of the water cycle, trees transpire water back into the atmosphere. c. Transpiration provides much of the daily rain in rainforest. A B 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.

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

Slide # 13 Structure of a Flower 2. Stamen: male reproductive structure a. Filament: thin stalk; supports anther b. Anther: knob-like structure; produces pollen c. Pollen: contains microscopic cells that become sperm cells Stamen Anther Filament Ovule Stigma Pistil Style Ovary Petal Sepal

Slide # 14 Structure of a Flower 3. Sepals: encloses & protects flower before it blooms Stamen Anther Filament Stigma Pistil Style Ovary 4. Petals: usually colorful & scented; attracts pollinators Ovule Petal Sepal

Slide # 15 Cross Pollination • 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.

Slide # 16 Chapter 25 Plant Responses and Adaptations

Slide #17 Hormone Action on Plants 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: Movement of hormone Hormoneproducing cells Target cells 1. Plant growth & development 2. Plant responses to environment Cells in one blooming flower signals other blooms using hormones to open.

Slide # 18 C. Plant cells will send signals to one another to tell them: 1. When trees to drop their leaves. 2. When to start new growth. 3. When to cause fruit to ripen. 4. When to cause flowers to bloom. 5. When to cause seeds to sprout. Tree Budding Fruit Ripening Cactus Blooming Leaf Drop Sprouting Corn Seeds

Slide # 19 D. Ethylene causes Fruit to Ripen 1. Fruit tissues release a small amount of ethlyene 2. Causes fruits to ripen. 3. 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.

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

Slide # 21 What type of tropism is shown in these pictures? m s i p m s i o e G P ho p o r t to p o tr m s i m g i Th o r t oto o h p o r t Ph m s i h p o m s i p o tr o e G m s i m g i h T r t o

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