Plant Structures & Functions

Plant Structures &

Functions

Describe the Structure & Function of Roots

1. Functions:

a. anchor plants

b. absorb water

c. store food: tubers(potatoes, carrots, beets)

d. may produce runners which grow into new plants

Magnified root tip

Grass rootstree roots

2. Structures:

a. root hairs- tiny hairs that absorb water and minerals

b. Cortex-bulk of root, transports water to vascular core

c. Parenchyma-makes up cortex, may act as storage

d. Vascular cylinder-xylem and phloem of the root

e. endodermis-single cell layer that controls flow of water into vascular bundle

f. Apical meristem-where growth occurs

g. Root cap- protective covering over end of root

Section 23-2

Epidermis

Ground tissue(cortex)

Vascular

Cylinder

Cross Section of Plant Root(magnification: 40x)

Ground tissue (cortex)

Epidermis

Endodermis

Vascular cylinder

Root hairs

Phloem

Xylem

Apical meristem

Root cap

Zone of maturation

Zone of elongation

Endodermis

Figure 23–7 The

Structure of a Root

Describe Stems1. Functions:

a. transport food and waterb. support growth above ground

2. Types:a. herbaceous-soft, fleshy stems

b. woody-hard stems, produce growth rings, have bark

d. dicot stems-vascular bundles concentrated in the cortex

c. monocot stems-vascular bundles are scattered

Describe Leaves

1. Function: site of photosynthesis

2. Types:a. simple-single blade

b. compound- leaf is made up of several parts

3. Veination

a. pinnate leaves-have central vein, all others rise from it

b. Palmate veins-veins arise from central spot, usually have 5 main veins

c. Parallel veins- veins all run in parallel lines down length of leaf

4. Arrangement

a. whirled- leaves whirl around stem

b. Alternate- leaves alternate on stem from one side to another

c. Opposite- leaves are directly opposite each other

5. Structures:

a. petiole- stalk joining leaf blade to the stem

b. Cuticle-waxy covering to protect from water loss

c. Palisade layer- column shaped cells containing chloroplasts, site of most photosynthesis

d. Spongy mesophyll- loosely packed with air spaces allowing gases to circulate

e. Stomata- openings in leaf for gas exchange

f. Guard cells- cells which control the size of the stomata

6. Leaf adaptationsa. spines- cactus

spines protect the plant from predators & water loss

B. Tendrils-leaflets that are modified for climbing

D. Pitcher type leaves-modified for catching insects

C. Thick leaves-modified for water storage

Photosynthesis in Plants1. Chlorophyll- green pigment in plants

a. converts light energy to chemical energy in the form of carbohydratesb. sugars can be broken down to release ATP

2. Photosynthesis- process where plants trap energy to build carbohydrates

a. CO2 + H2O + light C6 H12 O6 + O2

Quiz 3

Put your notes away and get

ready for your quiz,

Quiz 3

1. ____ is a function of roots.

a. eliminate water b. fertilization c. to anchor it

2. Which is a structure of a root.

a. cilia b. Cellulose c. Root Hairs

3. The ______ is a function of stems.

a. fertilization b. anchor c. support

4. ______ have vascular bundles centered in cortex.

a. dicot b. monocot c. both

5. The function of leaves is ______________.

a. photosynthesis b. fertilization c. support