1. Ch. 7
Plant Transport Part 1

2. Need for Transport Systems
Take in substances from environment
Get rid of waste
(cell respiration)

3. Transport Systems in Different Organisms
Single-celled organism
Large, multicellular organism
Transport occurs quickly
No point in the cell is very far from the surface; diffusion from anywhere in the cell can occur quickly with cell membrane
Gasses diffuse easily from any point within cell
Large surface area to volume ratio
Diffusion NOT sufficient b/c:
Centre of organism may be a long way to the surface
It would take too long for substances to diffuse all the way
Surface area to volume ration of cell is large

4. Large, multicellular organism
Solutions to transport problems:
Transport Systems
Increase surface area of parts of body involved in exchange with the environment
Ex. Thin, flat leaves
Ex. Highly folded gas exchange surface
Ex. Cristae in mitochondria
Ex. Grana (granum)
Ex. Alveoli
Diffusion NOT sufficient b/c:
Centre of organism may be a long way to the surface
It would take too long for substances to diffuse all the way
Surface area to volume ratio of cell is large

5. Transport in Plants
Large organisms with branching shape (helps keep surface area to volume ratio large)
Small energy needs compared to animals
Respiration does not take place as quickly
Rely on diffusion to supply cells with O2 and remove CO2
Role and structure of Leaves
Thin
large surface area inside in contact with air spaces
Diffusion is sufficient to supply mesophyll cells with CO2 for photosynthesis and remove O2
Plant transport systems Do NOT transport gas
2 transport systems

6. Two Transport Systems in Plants
Xylem
Transports water and inorganic ions from roots to other parts of plant
Phloem
Transports substances made in plant (sucrose and amino acids) to all parts of the plant
Important:!
Do NOT transfer GAS
SLOW transfer (not rapid)
NO pump involved (like heart)

7. Transport in Phloem
Translocation movement of ORGANIC substances in phloem tissue
Main substances moved (in solution):
ASSIMILATES (substances that have been made by plants)
Amino acids
Sucrose

8. Xylem: Water movement Driving force moving water: TRANSPIRATION
Loss of water vapour from a plant
Occurs mostly in leaves
Contain many cells in contact with air spaces in the mesophyll layers
Liquid water in cells changes to water vapour
Water vapour then DIFFUSES into the air spaces
Water vapour then diffuses out of the leaf through the STOMATA (down water potential gradient) into the air surrounding the leaf
Guard cells control opening and closing of stomata (change shape depending on conditions)
Photosynthesis requires OPEN stomata
CO2 comes in and water vapour leaves
Water loss is inevitable

10. Factors Affecting Transpiration
High Temp
High Humidity
High Wind Speed
High Light intensity

11. Points to Note about Plant Cells
Plant cells very similar to animal cells PLUS extra structures
Usually large than plant cells
Plant cell size varies
Cell wall of plants very different than cell membrane
Cell walls: thick, strong, freely permeable
Cell membrane: thin, partially permeable
Vacuoles are NOT confined to only plant cells
Plant cells have LARGE, PERMENENT CENTRAL vacuole
Animal cells have SMALL, TEMPORARY PHAGOCYTIC vacuoles

12. Plasmodesmata (singular: Plasmodesma)
Fine strands of cytoplasm that connect neighboring plant cells
Pass through pore-like structures in cell walls
Movement through pores is thought to be controlled by the structure of the pores

14. Division of Labor Cells Tissues Organs System
Basic unit of life; specific function
Tissues
Specialized groups of similar cells with common function
Organs
Specialized groups of tissues working together to perform a specific task
System
Group of specialized organs that work together to perform a common task

16. Plant Cell Types
Xylem Cells
Phloem Cells

19. Tissues Histology: study of tissue
Collection of cells and any intercellular secretion produced by these cells that are specialized to perform particular functions
Maybe same type of cell
Ex: parenchyma in plants
Ex. Squamous epithelium in animals
Maybe mixed type
Xylem and phloem in plants\cartilage, bone, blood, and connective tissue in animals

20. Three Main Types of Plant Tissue
Dermal Tissue
Protective outer covering of plant
Young plantssingle layer of cells
Older plantscan be many layers thick
In roots, dermal tissue includes root hairs
Vascular Tissue
Supports plant body
Transports water and nutrients throughout plant
Two types: xylem and phloem
Ground Tissue
Neither dermal nor vascular
Produces and stores sugars
Contributes to physical support of plant
Edible parts of potato, asparagus, squash are made of ground tissue
Can Consist of three types of cells:
PARENCHYMA cells (thin cell wall and large central vacuole)
In leaves, parenchyma cells contain many chloroplasts
COLLENCHYMA cells have strong flexible cell wall; help support plant organs
Strings in celery is made of long chains of collenchyma cells
SCLERENCHYMA cells have EXTREMELY thick cell wall
Makes strong ground tissue such as seed coats
Sclerenchyma fibers are used to make rope; shell of walnut

21. Organs
Part of body of organism which forms a structural and functional unit
Composed of more than 1 tissue
Examples of plant organs:
Leaves
Stems
Roots
Examples of animal organs:
Brain
Heart liver
Eye
kidney

23. Systems Collection of organs with particular function
Examples in plants:
Vascular System (xylem and phloem)
Examples in animals:
Excretory system
Reproductive system
Cardiovascular system
Digestive system

24. Angisperm (Flowering)Plant Classification
Monocots
Dicots

27. TISSUE IN DIFFERENT
PLANT ORGANS

28. Root Tissues Dermal Tissue Epidermis Vascular Tissue Pericycle Xylem
Phloem
Ground Tissue
Cortex
Endodermis

29. Stem Tissues
Epidermis: surface of the stem made of a number of layers often with a waxy cuticle to reduce waterloss.
Cortex Tissue: Forming a cylinder of tissue around the outer edge of the stem. Often contains cells with secondary thickening in the cell walls which provides additional support.
Vascular bundle: contains xylem, phloem and cambium tissue.
Xylem: a longitudinal set of tubes that conduct water from the roots upward through the stem to the leaves.
Phloem (sieve elements) transports sap through the plant tissue in a number of possible directions.
Vascular cambium is a type of lateral meristem that forms a vertical cylinder in the stem. The cambium produces the secondary xylem and phloem through cell division in the vertical plane.
In the centre of the stem can be found the pith tissue composed of thin walled cells called parenchyma. In some plants this section can degenerate to leave a hollow stem.

31. (c) Epidermis produces a waxy cuticle for the conservation of water.
LEAF Tissues:
(a) Phloem transports the products of photosynthesis (sugars, amino acids).
(b) Xylem transports water and minerals into the leaf tissue from the stem and roots.
(c) Epidermis produces a waxy cuticle for the conservation of water.
(d) Palisade layer which is the main photosynthetic region.
(e) Spongy layer creates the spaces and surfaces for the movement of water and gases.
(f) Lower epidermis contains the stomatal pores which allow gas exchange with the leaf.
The xylem and phloem tissues combine in the vascular tissue to provide support to the leaf.

33. Plan Diagram
You will usually have to do a plan diagram of an organ (ex. A leaf)
Organ contains many different types of cells arranged in a particular pattern characteristic of the organ, with cells of a similar type
This is a distinctive “tissue”
Drawing that shows where different TISSUES are located
Shows OUTLINE of the various TISSUES in an organs
Does NOT show individual cells