BI 103 Lecture Notes:
Ch 24 Plant Anatomy and Nutrient Transport
I. Angiosperm (Flowering Plant) Anatomy
A) Basics
1)
Root system (Functions: anchor, absorption, storage, transport, hormones, symbiotic connections.)
2)
Shoot system (Functions: photosynthesis, transport, reproduction, hormones)
B) Groups of
Angiosperms: (see fig. 24-2 in text)
1)
Monocots
2)
Dicots
II. Plant Growth
A) Plant growth
is indeterminate
B) Plants have
Meristem cells and Differentiated cells
C) Forms of Plant
Growth
1)
Primary Growth from Apical Meristems ( at tips; growth in length)
2)
Secondary Growth from Lateral Meristems (lining stem and roots; diameter)
III. Tissue Systems
A) Dermal Tissue
System
1)
Epidermal Tissue
a)
includes cuticle, root hairs
2)
Peridermal Tissue
b)
found only in woody plants (“with bark”)
B) Ground Tissue
System (see fig 24-5)
1)
Parenchyma
2)
Collenchyma
3)
Sclerenchyma
C) Vascular
Tissue System
1)
Xylem- Water, nutrients
a)
tracheids
b)
vessel elements
2) Phloem- photosynthate, hormones
a)
Sieve tubes
b)
Companion cells
IV. Plant Structures
A) Roots
1)
root cap
2)
epidermis
3)
Cortex
a)
innermost layer of the cortex is Endodermis: regulation function
4)
Vascular cylinder
a)
xylem, phloem
b)
pericycle (what does the pericycle do?)
B) Stem Anatomy
1)
Epidermis
2)
Cortex
3)
Pith
4)
Vascular tissue
C) Stem growth
1)
Primary growth (Growth in length of stems and branches: All plants)
a)
terminal buds and lateral buds
2)
Secondary Growth in stems (Growth in width/diameter: Only in some plants)
a)
Vascular Cambium
b)
Cork Cambium
D) Leaves (Solar
collectors)
1)
petiole
2)
blade
V. Plant Nutrient Acquisition
A) Plants need:
1)
Carbon 2) Oxygen 3) Hydrogen 4)Phosphorus 5)
Nitrogen 6) Mg, Ca, K
B) Processes for
acquiring minerals (from soil)
1)
Minerals actively transported into root hairs
2)
Minerals diffuse through cytoplasm and plasmadesmata to pericycle cells
3)
Minerals actively transported in to extracellular space of vascular tissue
4)
Minerals diffuse down concentration gradient into xylem via perforations.
C) Nutrient
acquisition via symbiotic relationships
1)
Fungal mycorrhizae: Increases mineral absorption
2)
Bacteria: Increase N absorption
VI. Water Acquisition
A) Secrets of
water transport
1)
Cohesion-Tension theory
B) Stomatal
Control of Transpiration
Determined
by
1)
Light reception
2)
Carbon Dioxide Concentration
3)
Water Concentration
C) Guard cells:
Control size of Stomata
1)
Regulated by [K+] in guard cell
VII. Sugar Transport (Hydrostatic pressure gradient drives
flow)
1) Pressure Flow
theory (higher pressure at source (e.g. leaves) to low pressure at sink (e.g.
fruit))
1) Sucrose
synthesized (photosynthesis)
2)
Loaded into Phloem sieve tube (by companion cells)
3)
Water follows (osmosis), increases pressure in phloem by source
4)
Sucrose unloaded at sink (active, by companion cells)
5) Water
exits also (osmosis), decreases pressure