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