1. Plant Unit Notes 4 of 5
Name: Hour:
Chapter 29: Plant Structure & Function (of roots, stems, & leaves) Pages Targets: 18-24

2. Review of Main Plant Cell Parts:
Large fluid-filled vacuole - provide turgor pressure for support & store water for dry spells
Plastid: pigment containing organelles
Thick cell wall - made of cellulose for support, that surrounds the cell membrane

3. Plants are made up of 3 types of cells
Parenchyma Cells
Thin flexible cell walls, cube-shaped
Large central vacuole
Function: photosynthesis, storage, & healing
Ex: flexible green stems, & fleshy fruit (Apples)
Collenchyma Cells
Thicker cells walls; irregular shape
Function: support for growing plant parts
Ex: areas still lengthening (Celery stalks)
Sclerenchyma Cells
Thickest/rigid cell wall
Function: strength & support for non growing plant parts; usually dies at maturity
Ex: a frame to support the plant (shell on nut)

4. 3 Types of Plant Tissue Systems
Location
Function in Roots
Function in Stems
Function in Leaves
Dermal Tissue (epidermis)
outer most layer -cuticle -stomata
absorption; protection
gas exchange; protection
Ground Tissue
b/w dermal & vascular
support; storage
Photosynthesis
Vascular Tissue
Tubes throughout plant
transport; support

5. Vascular Plant Tissue:
Xylem:
- Dead at maturity
- Transports water
- 2 Cell Types
- Tracheid: tapered ends;
pits to allow water to pass through
- Vessel Elements: larger holes at top & bottom
Phloem:
- living at maturity
-Transports organic material
- 2 Cell Types
- Sieve Tube: filters
- Companion Cell: assists in transport along sieve tube

6. Plant Growth:
Meristems: where plant growth originates (cells continually divide)
Apical Meristems: increase tips
Location: Tips of stem & root
Intercalary Meristems: increase length b/w nodes
Location: b/w tip and base of stem & leaves *why grass can regrow after being mowed
Lateral Meristems: increase diameter
Location: outsides of stems & roots
2 Types:
Vascular cambium (b/w xylem & phloem)
Cork cambium (outside phloem = makes cork)
Primary Growth: growth in length (apical & intercalary)
Secondary Growth: growth in width (lateral)

7. Concept Check What is the function of a plant vacuole?
- provide turgor pressure for support & store water for dry spells
Name the 3 types of plant tissues
- dermal, vascular, ground (a 4th could be meristematic)
Name the 3 types of cells found in plants
- Parenchyma Collenchyma Sclerenchyma

8. Plant Organs: Roots (typically grow underground)
Function: anchor in place, transport water & mineral nutrients, and storage of water & organic compounds
Types of roots:
Taproot: 1st root is the largest; generally not deep rooted
Ex: Carrot, radish
Fibrous Root System: numerous roots develop & branch
Ex: Grass
Adventitious: grow roots from above ground parts (stems & leaves); prop roots of corn & aerial roots of vines

9. Root Structures Root cap : protects apical meristem, produces “oil”
Root hairs: increase surface area for water absorption (mycorrhizal fungi)
Cortex: ground tissue just inside of epidermis
Endodermis: ground tissue found inside the cortex; has a waterproof substance to control water & mineral movement
Vascular Tissue: innermost core of roots.
Dicot: “X” shaped xylem with pockets of phloem
Monocot: pith in the middle with alternating xylem & phloem in a ring
Pericycle: outer layer of vascular tissue; produces lateral roots

10. Plant Organs: Stems (typically above ground, upright & woody or non-woody)
Function: support leaves, transport material, provide storage
Special Types of stems: (due to adaptations to the environment)
Stolons: grow along soil to produce new plants
Tubers: underground; modified for storing energy as starch
Fleshy stems: store water and carry out photosynthesis

11. Stem Structures Node: where a leaf is attached to a stem
Internodes: space between the nodes
Bud: where a new shoot can grow (stem or leaf)
Bud scales: cover buds; leave scars after opening
Primary Growth
Pith: forms in center of stem in dicots; separates from cortex
Vascular Tissue:
Monocots: xylem/phloem in scattered bundles
Dicots: xylem in/phloem out; form a ring in the cortex
Look at extra picture handouts!

12. Stem Structures - Continued
Secondary Growth: stems increase in thickness due to division of vascular cambium cells (b/w xylem & phloem)
Wood: secondary xylem
Heartwood: darker wood; older, does not transport water
Sapwood: lighter wood; still transports water
Bark: phloem near outside of stem; for protection (made of cork, cork cambium, and phloem)
Springwood: wood cells wide & thin walled; more water present
Summerwood: wood cells small & thick walled; lack of water
Annual Ring: created by difference in appearance (not seen in tropical plants, why?)

13. Stem Function: transport, storage, support leaves
Transport of sugar through phloem (translocation)
From source to sink by Pressure Flow Hypothesis
Source: where sugar is made or stored
Sink: where sugar will be stored or used
*sugar mainly made in leaves - moved to rest of plant
Transport water & dissolved minerals through xylem (transpiration)
Water pulled up by Cohesion-Tension Theory
Water molecules stick together; cohesion
Water molecules stick to xylem; adhesion
Water evaporates through stomata & pulls others along
Storing water and nutrients
Large amount of parenchyma cells to store:
Water; cactus / Sucrose; sugar cane / Starch; potatoes

14. Plant Organs: Leaves (typically thin & flat)
Function: Capture sunlight for photosynthesis
Types of leaves:
Tendrils: used to support & climb
Spines: protection; non-photosynthetic
Food traps: plants with poor soil nutrients
Structure:
Blade: broad flat portion of leaf
Petiole: stalk-like attachment to stem
Simple leaf: single blade
Compound leaf: blade is divided into leaflets
Can be doubly compound; leaflets divided

15. Leaf Structures Epidermis: Outside layer of cells
Cuticle: waxy covering; prevent water loss
Hairs: protect against insects & sun
Stomata: tiny air pores, areas for gas exchange;
number & location vary on plants
Guard cells: regulate the size of the stomata
Mesophyll: Ground tissue; chloroplast-rich
Palisade: under upper-epidermis; tightly packed
Spongy: under palisade layer; loosely packed, air spaces
Veins: bundles of vascular tissue (parallel vs. branched)

16. Concept Check What is the function of the root cap?
- protects apical meristem, produces “oil”
What are the main differences b/w xylem & phloem?
- xylem: dead at maturity; transports water; specialized cells: tracheid/vessel elements
- phloem: alive at maturity; transports food; specialized cells: companion/sieve tube
What difference b/w the stomata & the guard cells?
stomata = space; gas (O2/CO2) passes through
guard cells = cells; swell/shrink to control size of space