Plant Biology Fall 2006
BISC 367 - Plant Physiology Lab
Spring 2009
1.0
Plant Physiology Lab
Spring 2009
Professor:
Dr. Aine Plant, office B8228
e-mail: aplant@sfu.ca (preferred)
Tel: 778-782-4461
Lab Instructor: Doug Wilson, office B9239
e-mail: dwilson@sfu.ca
TA:
Lectures:
Owen Wally
e-mail: owenw@sfu.ca
Tuesday at 11:30 - 12:20
AQ 4120
Lab & tutorial: Thursday
1:30 - 5:20 in B8241
Thursday 11:30 to 12:20 in B8241 (not in AQ5049)
1.1
Mark distribution:
2 quizzes
2 lab reports
10 % each
17.5 %
each
Lab report based on project 25 %
Lab worksheets
20%
Quiz 1:
Quiz 2:
Tuesday Feb. 10
Project report due:
First week of exams
Textbook:
Taiz and Zeiger “Plant Physiology” 4th edition
On reserve in the library
Tuesday Mar. 24
1.1
Online material: http://www.sfu.ca/bisc/bisc367/
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Course outline
Lab handouts
Posted lecture presentations
Lab project data and info.
1.1
Plant Physiology Lab
Spring 2009
Notices:
General reading:
• Chapter one focus on:
• Tissues
• Chloroplasts
• Plasmodesmata
• Chapter 15 covers cell walls. Cover the basics only!
Overview - plant morphology
Shoot system
• Stem
• Supports and places leaves
• Transports H2O and nutrients
• Leaves
• Photosynthesizers
• Reproductive structures
Root system
• Anchors plant
• Absorbs water and minerals
• Storage (CHO) & synthesis of some hormones
Overview - plant morphology
3 major tissue systems make up
the plant body
• Ground tissue
• cortex
• mesophyll
• pith
• Vascular tissue
• Dermal tissue
• Tissue systems are continuous
throughout the plant
3 Tissue Systems
• Ground tissue includes:
• Parenchyma tissue
• Collenchyma tissue
• Sclerenchyma tissue
• Vascular tissue includes
• Xylem tissue
• Phloem tissue
• Dermal tissue
• Epidermis
Tissue Systems
• Parenchyma tissue:
• SIMPLE
– Made up of a single cell type
• Cells are ALIVE at maturity
• Capable of dividing
– TOTIPOTENT
• Involved in wound regeneration and range of metabolic fxns
Tissue Systems
• Chollenchyma tissue:
•
•
•
•
SIMPLE
Cells are ALIVE at maturity
Contain unevenly thickened walls
Support young growing stems and organs
Tissue Systems
• Sclerenchyma tissue:
•
•
•
•
SIMPLE
Cells are dead at maturity
Typically lack protoplasts
Possess secondary walls with lignin
– Strong polymer
• Support stems and organs that have stopped growing
fibres
sclereid
Economically important tissue!
e.g. Hemp fibres
Tissue Systems
• Xylem tissue:
• COMPLEX
– Made up from more than one cell type
• Functions
– Conduction of H2O
– Structural support
• Cells are elongated & dead at maturity
• Lack protoplasts
• Possess elaborately thickened secondary
walls with lignin (very strong)
• 2 main cell types
–
–
Vessel members
Tracheids
Tissue Systems
– Tracheids (primitive):
• Tracheids “stack” longitudinally in the stem overlapping at
tapered ends
Tracheid 1
Pits
Tracheid 2
How does H2O pass from one tracheid to the next?
• Passes through aligned pits of neighbouring
tracheids
• Pit membrane consists of 1o wall only
Tissue Systems
– Vessel members (advanced):
• Stack end to end to form a vessel (long)
• Perforation plate at ea. end of a member permits easy water flow
3 vessel
members
stacked end to
end to form
part of a
vessel
Slotted perforation plate forms
end wall of a vessel member
Water passes from vessel to vessel via pits
Tissue Systems
• Xylem is a complex tissue:
– Also present
• Parenchyma tissue (nutrient storage)
• Fibres/sclereids
Tissue Systems
• Phloem tissue
– Complex
– Functions
• Conduction of nutrients
– Cells are alive at maturity but highly modified
• Lack:
– Nucleus
– Definition between cytoplasm and vacuole
– 2 main cell types
• Sieve cells
• Sieve tube members
Tissue Systems
– Sieve tube members (advanced)
• Elongated cells
• Sieve tube members stack end to end to form a sieve tube
• End walls form sieve plates and contain pores that connect the the
cytoplasm of two sieve cells for solute transfer
Sieve tube member 1
Sieve plate
Sieve tube member 2
Tissue Systems
– Sieve tube members and sieve cells are connected to
specialized cells
A sieve tube member is always
associated with a companion cell
• Connected via plasmodesmata
• companion cell provides:
• metabolic functions
• Loads sugars for
transport
Tissue Systems
• Dermal tissue
– Functions
• Mechanical protection
– Made up of epidermal (parenchymal) cells
• Cells overlaid with a waxy cuticle to minimize H2O loss
Waxy cuticle
Tissue Systems
Dermal tissue
– Also present
• Guard cells
– Regulate size of the stomatal pore and
• Movement CO2 into leaf
• Movement H2O vapour out
Stomatal pore
Tissue Systems
Dermal tissue
– Also present
• Trichomes aka “hairs”
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–
–
–
Increase reflectance of solar radiation
Absorb H2O and minerals (epiphytes)
Contain chemical defenses
Can impale larvae of some insects
Branched &
glandular trichomes
Root anatomy
• Root structure
– Simple
– Epidermis (outer layer of cells)
• Protects root
• Plays important role in water uptake
– Facilitated by root hairs
– Tubular extension from epidermal cell
• Increases surface area for water uptake
– Produced in zone of maturation
• Short lived
Root epidermal cell with root hair
Root anatomy
– Cortex
• Ground tissue that occupies
most volume of root
• Cells often adapted for
storage
– Starch
• Numerous air spaces exist
– Roots need to respire!
• Innermost boundary of cortex
is the endodermis
Root anatomy
– Vasculature in a eudicot root
• Protostele
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–
–
–
Vascular tissue occupies the centre of root
Xylem arranged as a “star”
Phloem tissue is located between the arms of the xylem “star”
Pericycle tissue surrounds vascular tissue
Root anatomy
– Vasculature in some monocot roots develops with a central pith
Central pith
Maize root
Stem anatomy
• Primary structure of a eudicot stem
– 1o vascular tissue are present as a
cylinder of strands separated by
ground tissue
• Interfascicular rays or pith rays
– 1o phloem is present at the outside of
the bundle
– 1o xylem is present on the inside of
the bundle
– Ground tissue in centre of stem is the
pith
– Ground tissue that lies outside the
vascular bundle is the cortex
– Outermost layer is the epidermis
• Contains stomata and trichomes
Stem anatomy
• Primary structure of a eudicot
stem
– Single layer of cells between 1o
phloem & 1o xylem remain
meristematic
• Become vascular cambium
– Cylindrical meristem that is
responsible for 2o growth
• Remainder of cambium arises from
interfascicular parenchyma
– Note, not all eudicots undergo 2o
growth
• No cambium arises
Anatomy of a woody stem
– Woody stem during first year of growth
Leaves
• Evolved to photosynthesize
– Divided into
• Blade or lamina
• Petiole or stalk
– Leaf anatomy is influenced by the amount of available water:
• Plants can be grouped according to their water requirements:
• mesophyte
– Plant with plentiful water supply
• hydrophyte
– Grows partially or completely submerged
• xerophyte
– Adapated to dry environment
Leaf anatomy
•
General features of mesophytic leaves (eudicot)
– Stomata more numerous on lower surface
• sheltered
– Photosynthetic tissue (mesophyll) is
differentiated into:
• Upper palisade parenchyma
– Upright cells with many cps
• Lower spongy mesophyll
– Permeated by air spaces
– Vasculature is netted venation
• Xylem towards upper surface
• Phloem towards lower surface
• Small veins collect P/S products
– Surrounded by a bundle sheath
– Controls entry/exit of material
• Large veins transport P/S products from
leaf
Leaf anatomy
– Anatomical modifications in
hydrophytes
• Problem = obtaining enough CO2 & O2
– Stomates not present or in upper
epidermis (floating leaf)
– Thin cuticle
– Large amounts of air in spongy
mesophyll
• Gas exchange
• buoyancy
– Reduced vascular tissue
• Partic. xylem
– Reduced amount of support tissue
Leaf anatomy
Modifications present in xerophytes
• Problem = getting enough water
– Many of these plants have reduced leaf
size or no leaves
– Large number of stomates
• Optimize gas exchange when
water is plentiful?
• Remember stomates usually shut
– Stomates generally sunk in depression
in leaf surface
• Assoc. with trichomes
• Both increase depth of boundary
layer & slow rate of water loss
– Thick cuticle
– Multiple epidermis
• Modified to store water
– More supporting tissue to compensate
for reduced turgor
Stomate
Leaf anatomy
– General features of monocot leaves
• Parallel venation system
• Lack a defined palisade/spongy mesophyll layers
–
Leaves tend to be vertically oriented
• Anatomy modified according to mode of P/S
– C4 photosynthesis
• Carbon fixed to form a C4 acid in mesophyll cell
• C4 acid is transported to bundle sheath cell & decarboxylated
• Released CO2 is refixed by C3 P/S
P/S
CO2 + C3 acid
CO2 + C3 acid
C4 acid
C4 acid
Mesophyll cell
Bundle sheath cell
Leaf anatomy
– Leaves of C4 plants display
Kranz anatomy
• Mesophyll and BSC form 2
concentric layers around a
vascular bundle
• Bundle sheaths are close
together
C4 leaf
– Leaves of C3 plants have well
separated bundle sheaths and
do not have Kranz anatomy
C3 leaf