1. KEY CONCEPT Plants have specialized cells and tissue systems.

2. Plant tissues are made of three basic cell types.
Parenchyma cells are the most common plant cell type.
store starch, oils and water
help heal wounds to the plant
have thin flexible walls

3. Collenchyma cells provide support to a growing plant.
they are strong and flexible.
celery strings are strands of collenchyma.
they have unevenly thick cell walls.

4. Sclerenchyma cells are the strongest plant cell type.
second cell wall hardened by lignin
die when they reach maturity
used by humans to make linen and rope

5. Plant organs are made of three tissue systems.
Dermal tissue covers the outside of a plant.
protects the plant
secretes cuticle of leaves
forms outer bark of trees

6. Ground tissue is found inside a plant.
provides support
stores materials in roots and stems
most commonly made of parenchyma

7. Vascular tissue transports water, minerals and organic compounds.
stem
leaf
root
two networks of hollow tubes
xylem transports water and minerals
phloem transports photosynthetic products

8. The cohesion-tension theory explains water movement.
Plants passively transport water through the xylem.
Cohesion is the tendency of water molecules to bond with each other.
Adhesion is the tendency of water molecules to bond with other substances.

9. Water travels from roots to the top of trees.
absorption occurs at roots
cohesion and adhesion in xylem
transpiration at leaves

10. Transpiration is the loss of water vapor through leaves.
water vapor exits leaf stomata
helps pull water to the top branches

11. Roots anchor plants and absorb mineral nutrients from soil.
Roots provide many functions.
support the plant
absorb, transport, and store nutrients
root hairs help absorption

12. There are several parts of a root.
root cap covers the tip
apical meristem is an area of growth
vascular cylinder contains xylem and phloem
vascular cylinder
apical meristem
root cap

13. Stems support plants, transport materials, and provide storage.
Stems have many functions.
support leaves and flowers
house most of the vascular system
store water
grow underground for storage
form new plants
Strawberry stolons

14. Primary growth increases a plant’s length.
Secondary growth increases a plant’s width.

15. Most leaves share some similar structures.
The blade is usually broad and flat.
collects sunlight for photosynthesis
connects to the stem by a petiole
blade
petiole

16. Mesophyll is between the leaf’s dermal tissue layers.
cuticle
upper
epidermis
palisade mesophyll
spongy mesophyll
lower epidermis

17. Guard cells surround each stoma.
Stomata open and close when guard cells change shape.
When stomata are open, water evaporates and gas exchanges.
Stomata close at night and when plant loses too much water.
guard cells
stoma

18. Leaves may be simple, compound, or double compound.
Simple leaf
Compound leaf
Double compound leaf

19. Leaf veins may be parallel or pinnate.
Pinnate veins
Parallel veins

20. Leaf margins may be toothed, entire, or lobed.
Toothed margin
Entire margin
Lobed margin

21. Leaves have many adaptations.
for extreme temperatures, ex: pine needles

22. Leaves have many adaptations.
for extreme temperatures, ex: pine needles
for water loss, ex: cactus spines

23. Leaves have many adaptations.
for extreme temperatures, ex: pine needles
for water loss, ex: cactus spines
for aquatic environments, ex: water lily
for getting food, ex: Venus’ flytrap

24. Plants can respond to light, touch, gravity, and seasonal changes.
Phototropism is the tendency of a plant to grow toward light.
auxins build up on shaded side of stem
cells on shaded side lengthen
causes stem to bend toward light

25. Thigmotropism is a plant’s response to touchlike stimuli.
climbing plants and vines
plants that grow in direction of constant wind
Thigmotropism A plant turns and bends in response to contact with an object.

26. Gravitropism is a plant’s response to Earth’s gravitational pull.
positive gravitropism is downward growth (roots)
negative gravitropism is upward growth (shoots)
Gravitropism Plant stems grow upward, against gravity.

27. Photoperiodism is a response to the changing lengths of day and night.
triggers some plants to flower (see below)
triggers fall colors/winter dormancy of deciduous trees
Photoperiodism A plant moves its leaves during the day.