Outline: Angiosperm Structure and Growth, Chpt 35, Bio 102 (Vogt)

A. Plant Cell
B. Gross Organization:

1. Root, Shoot and Leaf
2. Vasular System
3. Site of Photosynthesis

C. Two Angiosperm Divisions: Monocots and Dicots

II. Cell and Tissue Types

A. Three basic tissue types (structural): dermal, vascular and ground
B. Anatomy of shoot, root and leaf

A. Meristem Tissue - Cambium
B. Apical Meristem -- Root tip
C. Apical Meristem -- Shoot tip
D. Lateral Meristem -- bark

Lecture Notes: Plant Structure and Growth, Chpt 35

I. Plant Structure

A. Plant Cell: differences from animal cell... (Figs. 7.7-7.8, p.108-109)

1. cell wall: Fig. 35.9; cellulose (Figs. 5.7, 38.18, 38.19)lignin in some for strength
2. cell vacuole: hydrostatic (36.4, p.699)
3. chloroplasts: in location-specific cells (10.2, p.170)

B. Gross Organization:

1. Root, Shoot and Leaf (35.4, p.673)
2. Vasular System -- xylem and phloem

a. xylem
b. phloem

3. Sites of Photosynthesis - in chloroplasts within cells near surfaces of leaves and stems (31.19, p. 685)
4. Environmental Adaptations - (> 250,000 different species)

shapes to fit the situation

leaf shape, branch pattern, size, vine vs. free standing, etc.

plants can have dramatically different forms
habitat dependent

C. Two Angiosperm Divisions: Monocots, Dicots Figs. 35.3, 35.16, 35.19,

1. Monocots:
• One cotyledon
  
• Veins usually parallel
  
• vascular bundles complexly arranged
  
• fibrous root system
  
• floral parts usually in multiples of 3
  
• grasses, palms, bamboos, lilys, orchids, yuccas
  
• growth can be at base of leaf (cutting grass does not remove growth region)

2. Dicots:
• Two cotyledons
  
• Leaf veins usually netlike
  
• Vascular bundles usually arranged in ring
  
• Taproot usually present
  
• Floral parts usually in multiples of 4-5
  
• Most angiosperms
  

II. Plant Tissues and Cell Types: the players...

A. Three basic tissue types (structural): Dermal, Ground, Vascular

(fig. 35.12, 35.10)

1. Dermal: epidermis and endodermis / cuticle / periderm / cork

2. Ground tissue:


Parenchyma: thin walled, diverse functions (PS, storage, etc.)
Collenchyma: support, herbaceous plants / celery
Sclerenchyma: support, lignin; fibrous hemp/jute

3. Vascular Tissue: tubes

Xylem:

i. dead cells : tracheids, vessel elements (35.11)
ii. water and minerals from roots to leaves
iii. evaporation (transpiration) and H₂O cohesion

Phloem:

i. live cells : sieve tube member, companion cells (36.14)
ii. sugar, nutrient, hormone transport witnin plant
iii. metabolically driven osmosis (PS driven)

B. Anatomy of shoot, root and leaf

1. Anatomy of Shoot (Fig. 35.19)

• Upright structure, Distributing leaves for light access, fluid transport upwards.
  a. Epidermis - waxy cuticle
  b. Cortex - Collenchyma, Parenchyma, Sclerenchyma
  c. Vascular Tissue - Ring (in Monocots - distributed throughout)
  
  i. Xylem
  ii. Phloem
  iii. Vascular Cambium
  - undifferentiated
  
  - xylem, phloem, branch apical meristem
  
  d. Pith
  e. Annual growth
  
  i. secondary phloem and xylem
  ii. cork cambium
  
  - cork
  - bark - vascular cambium outward

2. Anatomy of a Root (Figs. 35.15, 35.16, 36.6)

• Anchorage, Fluid & Nutrient Uptake, Nutrient Storage
  a. Epidermis - root hairs
  b. Cortex
  c. Endodermis - pericycle - Casparian strip
  d. Vascular Column - central core
  
  i. Xylem
  ii. Phloem
  iii.Vascular Cambium - undifferentiated
  
  xylem, phloem, secondary root apical meristem

3. Anatomy of a Leaf (Fig. 35.20)

• optimized for gas exchange, PS (CO₂ limiting - need for transpiration)
  a. epidermis -
  
  i. waxy cuticle
  ii. stoma / guard cells
  
  - open daylight, closed dark, closed under water stress
  
  b. mesophyll - very airy
  
  i. palisade layer - chloroplasts
  ii. spongy layer - chloroplasts
  
  c. vascular bundles
  
  i. xylem & phloem
  ii. bundle sheath cells
  

III. Plant Growth

Dicots (Fig. 35.15):
• Shoot Apical Meristems (incl. Axillary Buds)
  
• Root Apical Meristems (incl. lateral roots)
  
• Lateral Meristems (incl. "secondary Growth" Fig. 35.24)

A. Meristem Tissue - a.k.a. Cambium


1. Growth from specialized centers undifferentiated cells (cambium)
2. localized cell division (meristem).
2. Sites of cell division restricted to:

a. shoot and root tip (primary growth): apical
b. stem (secondary growth): lateral

B. Shoot Tip Apical Meristem (Fig. 35.18, 35.21)

1. Growth Tips

a. Terminal Buds
b. Apical meristem (35.21)

2. Axillary Bud (35.21)

C. Root Tip Apical Meristem (Fig. 35.15)

1. Growth tips, root cap, apical meristem
2. zone of elongation
3. zone of maturation
4. Lateral roots (Fig. 35.17)

D. Lateral Meristem -- stem diameter (Fig. 35.23, 35.24, 35.25)

1. cambium cells divide, differentiate to xylem or phloem
2. assymetric differentiation
3. bark: sloughing phloem
4. Secondary Growth: Vascular Cambium + Cork Cambium (Fig. 35.24)

E. Monocots vs. Dicots: one vs. two cotyledons (embryonic leaves)

1. Monocots: grasses, irises, lilies

a. parallel leaf veins
b. growth from base of leaf, tip of root

2. Dicots: all others,

a. networked veins in leaves
b. growth from stem and root tips

Vocabulary