Slide 1 Structure of Plants

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

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

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

A. Functions of Stems Support system for plant body 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.

A. Functions of Leaves Main photosynthetic organ 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

B. Leaf Structures Leaf Cross-Section Slide # 7 Leaf Cross-Section 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. Cuticle Veins Mesophyll Stoma (Opening) 2 Guard Cells Surround each Stoma Stoma- singular Stomata-plural

cells that open and close the stoma 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

Function of Stomata Slide # 9 What process involves using CO2 and H2O 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 What goes out? O2 H2O CO2 What goes in? Stoma Open Stoma Closed Stoma

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 Open Stoma Closed Guard cells open by inflating with extra water. They do this by pumping K+ ions into the cell, which causes water to rush in via osmosis to diffuse the high ion concentration.

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. 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.

Structure of a Flower 1.Pistil:female reproductive structure Slide # 12 Filament Anther Stigma Style Ovary Pistil Petal Sepal Ovule Stamen 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

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

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

Cross Pollination How does pollination happen? 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.

Plant Responses and Adaptations Slide # 16 Chapter 25 Plant Responses and Adaptations

Hormone Action on Plants Hormone-producing cells Hormone Action on Plants 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.

C. Plant cells will send signals to one another to tell them: Slide # 18 C. Plant cells will send signals to one another to tell them: 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 Tree Budding Fruit Ripening Cactus Blooming Sprouting Corn Seeds

D. Ethylene causes Fruit to Ripen Slide # 19 D. Ethylene causes Fruit to Ripen 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.

Slide # 20 Plant Tropisms 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 closes when leaves are touched

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

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