Chapter 10
Plant Anatomy & Physiology
Michael G. Simpson
Plant Anatomy
Study of tissue and cell structure of plants.
(In zoology, anatomy is study of internal
organs; histology is study of tissues/cells.)
Plant Physiology
Study of metabolic processes in plants.
Cell Theory
All of life is composed of 1 or more cells.
Cells arise only from pre-existing cells, via
cell division or cell fusion.
Cells are units of metabolic processes.
Each cell contains set of hereditary
information (DNA), transferred from cell to
cell, coding for structural & functional
features.
transport &
modification
storage high
energy carbs.
contains DNA
structural support
respiration
cell recognition,
transport
photosynthesis
protein synthesis
& transport of
materials
ribosomes: site of
protein
synthesis
storage: pigments,
acids, ergastic
substances
Ergastic Substances:
not actively metabolized (storage/waste)
aleurone grains: protein
chromoplasts
druses
oil bodies
amyloplasts (starch grains):
alpha-1,4-glucopyranoside
raphides
crystals (Ca-oxalate; silica)
styloids
prismatics
cell wall
mainly cellulose:
beta-1,4-glucopyranoside
lignin - secondary cell wall
Cell #1
Cell #2
middle lamella
plasma
membrane
primary cell wall
(cellulosic)
secondary cell wall
(lignified)
function?
pit
(pits of two adjacent
cells = pit-pair)
primary pit field
(collection of several
plasmodesmata)
plasmodesmata
Cell #1
Cell #2
shoot
apex
internode
node
shoot apical
meristem
axillary
bud
bud
primordium
lateral
branch
shoot tip
lateral branch
root tip
shoot
root hairs
root
lateral roots
root apical
meristem
root cap
meristem - region of actively dividing cells
1) apical (shoot & root);
2) lateral (vascular & cork cambia)
Cell differentiation:
1) Cell expansion (elongation)
2) Cell maturation / specialization
Plant Tissues & Cell Types
Tissue:
= group of cells with common function or structure.
Three broad tissue types:
1) Dermal - outside layer(s)
2) Vascular - conduction
3) Ground - between dermal and vascular
Simple vs. Complex Tissue:
1 versus 2 or more cell types
Ground Tissue
Parenchyma: Gen. metabol.
1) Isodiametric to elongate
2) Primary cell wall
3) Living
Collenchyma: support
1) Elongate
2) Primary cell wall thick,
uneven, rich in pectins
3) Living
Ground Tissue
Sclerenchyma
1) Secondary cell wall (+ primary)
2) Dead at maturity (usually)
Fibers
Elongate, sharply tapering
Ground Tissue
Sclerenchyma
1) Secondary cell wall (+ primary)
2) Dead at maturity (usually)
Sclereids
Isodiametric to irregular
Vascular Tissue
Xylem
Water & mineral conduction
Tracheary elements + parenchyma + sclerenchyma
Phloem
Sugar conduction
Sieve members + parenchyma + sclerenchyma
- Both complex tissues
Tracheary Elements
Tracheids - Imperforate
Vessels - Perforate
Angiosperms (most)
Gnetales
A few Monilophytes
Sieve Elements
Sieve cells - No sieve plates
Sieve tube members - Sieve plates
Apomorphy of Angiosperms
Dermal & Secretory tissues & cells
Epidermis
Glands
Stomates
Nectaries
Laticifers
Dermal tissues: Trichome anatomy
Epidermis
lateral branch
root tip
shoot
root hairs
root
lateral roots
root apical
meristem
root cap
root cap
ROOT (l.s.)
1) Protective root cap
2) Absorptive root hairs
root apical
meristem
ROOT (c.s.)
3) Give rise to new roots endogenously
(from within)
Casparian Strip
Function: forces fluids
from outside
through plasma
membrane =
selective absorption
shoot
apex
internode
node
shoot apical
meristem
axillary
bud
bud
primordium
lateral
branch
shoot tip
lateral branch
root tip
shoot
SPOROPHYTIC
SHOOT
Stems:
• Give rise to leaves exogenously
• Do not have a protective “cap” of cells
• Do not have root hairs (but may have trichomes)
Stelar types
eustele
atactostele
Protoxylem maturation
Vascular cambium - a lateral meristem
Conifers: non-porous
Ring porous
Diffuse porous
Wood Ray Anatomy
Leaf anatomy
Stomata
C3
Photosynthesis
Kranz anatomy
C4 Photosynthesis
CAM photosynthesis