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# 16.2: Plant Organs: Roots, Stems, and Leaves

Difficulty Level: At Grade Created by: CK-12

## Lesson 16.2: True or False

Name___________________ Class______________ Date________

Write true if the statement is true or false if the statement is false.

_____ 1. Stems absorb water and minerals and transport them to the roots.

_____ 2. Roots contain dermal, ground, and vascular tissues.

_____ 3. Many plants with taproots use the root as a place to store food.

_____ 4. Fibrous roots anchor the plant less securely to the ground than taproots.

_____ 5. Root hairs detect gravity so the root grows downward.

_____ 6. Mycorrhizal relationships allow the plant to absorb more water.

_____ 7. Secondary stems grow from internodes on the primary stem.

_____ 8. Some plants have stems that can store water during dry seasons.

_____ 9. The only function of stems is to bear leaves and flowers.

_____ 10. The width of a tree ring represents a single year's growth in the width of the tree's stem.

_____ 11. The leaf petiole does the majority of photosynthesis for a leaf.

_____ 12. Microphylls are the leaves of flowering plants.

_____ 13. Plants with a basal rosette of leaves are taking advantage of higher temperatures close to the ground.

_____ 14. Compound leaves are made up of a number of leaflets.

_____ 15. Deciduous leaves change color in the fall when their chlorophyll breaks down.

Name___________________ Class______________ Date________

Read these passages from the text and answer the questions that follow.

Root Structures and Functions

The tip of a root is called the root cap. It consists of specialized cells that help regulate primary growth of the root at the tip. Above the root cap is primary meristem, where growth in length occurs.

Above the meristem, the rest of the root is covered with a single layer of epidermal cells. These cells may have root hairs that increase the surface area for the absorption of water and minerals from the soil. Beneath the epidermis is ground tissue, which may be filled with stored starch. Bundles of vascular tissues form the center of the root. Waxy layers waterproof the vascular tissues so they don’t leak, making them more efficient at carrying fluids. Secondary meristem is located within and around the vascular tissues. This is where growth in thickness occurs.

The structure of roots helps them perform their primary functions. What do roots do? They have three major jobs: absorbing water and minerals, anchoring and supporting the plant, and storing food.

• Absorbing water and minerals: Thin-walled epidermal cells and root hairs are well suited to absorb water and dissolved minerals from the soil. The roots of many plants also have a mycorrhizal relationship with fungi for greater absorption.
• Anchoring and supporting the plant: Root systems help anchor plants to the ground, allowing plants to grow tall without toppling over. A tough covering may replace the epidermis in older roots, making them rope-like and even stronger.
• Storing food: In many plants, ground tissues in roots store food produced by the leaves during photosynthesis.

Questions

1. Picture a plant's root cap. What additional function might it have that is not described in the above passage?

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2. How do root hairs increase the surface area for water and mineral absorption?

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3. What is a function of the ground tissue of a root?

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4. What are the three main functions of roots?

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5. What does the secondary root meristem do?

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## Lesson 16.2: Multiple Choice

Name___________________ Class______________ Date________

Circle the letter of the correct choice.

1. The main difference between a taproot system and a fibrous root system is that
1. taproots can store a lot of food, while fibrous roots do not.
2. taproots absorb water, while fibrous roots do not.
3. fibrous roots can access water sources deep under the ground, while taproots cannot.
4. fibrous roots have an epidermal cell layer, while taproots do not.
2. Roots grown downward because
1. they have vascular bundles.
2. they grow opposite to the force of gravity.
3. they grow away from water sources.
4. there are gravity-sensing cells in the root cap.
3. The xylem of the vascular tissue in the root
1. carries sugars from the leaves to the roots for storage.
2. carries water and minerals from the root up to the stem.
3. detects gravity and causes the root to grow downward.
4. none of the above
4. In stems, the ______ meristem is responsible for growth in length, and the _____ meristem is primarily responsible for growth in width.
1. secondary, primary
2. primary, secondary
3. node, epidermal
4. epidermal, node
5. A main function of the leaf petiole is
1. to extend the leaf blade away from the stem so the blade can collect sufficient sunlight.
2. to keep the leaf away from the secondary meristem of the stem.
3. to produce pollen.
4. none of the above.
6. Very thick stems are specialized for
1. clinging and climbing.
2. strength and support.
3. storing water or food.
4. photosynthesis.
7. Leaves arranged in whorls are optimized to
1. collect sunlight from all directions.
2. to increase resistance to wind.
3. to increase water loss.
4. to increase food storage capacity.
8. The air spaces in the leaf interior
1. block gas exchange between the mesophyll cells and the environment.
2. make the leaf weigh more than a leaf packed tightly with cells.
3. make the leaf weigh less than a leaf packed tightly with cells.
4. carry out most of the photosynthesis in the leaf.

## Lesson 16.2: Vocabulary I

Name___________________ Class______________ Date________

Match the vocabulary word with the proper definition.

Definitions

_____ 1. photosynthetic leaf cells

_____ 2. increases the surface area for absorbing water in the root

_____ 3. the type of roots a plant has

_____ 4. a plant that keeps its leaves for more than one year

_____ 5. a leaf pore flanked by two guard cells

_____ 6. a plant that loses its leaves yearly and grows new ones

_____ 7. a thick primary root often growing deep into the soil

_____ 8. the outermost woody covering of a stem

_____ 9. the tip of a root

_____ 10. the part of a stem from which secondary branches grow

_____ 11. the leaf part that supports and displays the leaf blade

_____ 12. has multiple, spreading roots without a main primary root

Terms

a. bark

b. deciduous plant

c. evergreen plant

d. fibrous root

e. mesophyll

f. node

g. petiole

h. root cap

i. root hair

j. root system

k. stomata

l. taproot

## Lesson 16.2: Vocabulary II

Name___________________ Class______________ Date________

Fill in the blank with the appropriate term.

1. The leaf ________, which is connected to the leaf petiole, is a very important photosynthetic part of a plant.

2. A ________ can grow deep into the ground to access water, and can also store food for the plant.

3. There are two main types of ________ in plants for absorbing water and minerals.

4. In the fall, ________ lose their leaves.

5. The ________ can close to reduce water loss from the leaf.

6. Even though part of it is nonliving, ________ functions to protect the living parts of the stem.

7. ________ consists of photosynthetic cells located in between the upper and lower epidermis of a leaf.

8. Plants with a _______ root system are less securely anchored to the ground.

9. A pine tree is an example of a(n) ________.

10. Leaves and secondary stems grow out of stem ________.

11. ________ are long, thin cells in the epidermal cell layer of roots.

12. The leaf is attached to the stem via a(n) ________.

## Lesson 16.2: Critical Writing

Name___________________ Class______________ Date________

Thoroughly answer the question below. Use appropriate academic vocabulary and clear and complete sentences.

Not all plant stems are the same. Name and describe three different stem types of plants and how they adapt a plant to its environment.

Feb 23, 2012

Oct 07, 2015