plant tissues 12 march 2014 lesson description summary
TRANSCRIPT
PLANT TISSUES 12 MARCH 2014
Lesson Description
In this lesson we:
Identify the different types of plant tissue
Be able to relate the different structures with the different functions
Summary
Plant Tissue
TISSUE LOCATION STRUCTURE FUNCTION
Meristematic Apical – tips of roots and shoots
Lateral – sides of roots and stems
Vascular cambium – between xylem and phloem of dicots
Cork cambium – inside cork cells
Thin willed
Large nucleus
No intercellular spaces
Regular shape
Actively dividing – Mitosis
Produce new cells for
Growth in length and width
Replace worn-out or damaged tissue
Differentiate into different types of tissue
Epidermis Outer covering of roots, stems and leaves
Stems and leaves
Guard cells surrounding a stoma
Regular shape
Thin walled
No chloroplasts
No air spaces
Covered with a cuticle
Roots
Regular shape
No cuticle
Outgrows – root hairs
Protect deeper-lying tissue
Cuticle reduced loss of water vapour by transpiration
Guard cells control opening and closing of stoma, control loss of water vapour and gas exchange.
In roots help to absorb water from soil.
Parenchyma Forms bulk of roots, stems, leaves and flowers.
Irregularly shaped round, oval
Thin-walled, large vacuole
Large intercellular spaces
Lack chloroplasts
Packing tissue
Stores food as starch or sugars
Intercellular air-spaces allow water and gases to pass through.
Chlorenchyma In upper layers of leaves and stems
Palisade and spongy mesophyll of leaves
Parenchyma tissue with chloroplasts
Thin-walled, irregularly shaped with intercellular spaces.
Elongated upper layer – palisade layer
Manufactures food y photosynthesis.
Collenchyma In epidermis of young stems
Regular shape
No intercellular spaces
Corners of cells are thickened
Give support and strength to above-ground parts
Sclerenchyma Fibres
In epidermis or stems
Cap around vascular bundles of dicot stems
Sheath completely around vascular bundle of monocots
Stone cells in shells of nuts and hard parts of fruits
Fibres
Long with tapered ends
Thick- walled
Very small inner cavities
Stone cells
Small, oval, irregular cells
Extremely thick walls with lumens almost completely blocked.
Give mechanical support to plant.
Xylem Within veins of leaves, vascular bundles of stems and stele of roots
Vessels
Cylindrical cells
Cross walls perforated or absent
No cell contents – dead cells
Form continuous tubes from roots to leaves
Thick walls (lignin)
Lignin laid down to form patterns
Tracheids
Ends tapered
Have perforated cross walls
Fibres and parenchyma as described above.
Vessels and tracheids transport water and mineral salts from roots to stems and leaves
Give strength and support
Phloem Within veins of leaves, vascular bundles of stems and stele of roots
Sieve tubes
Cylindrical cells
Cross walls perforated to form sieve plates
Thin-walled cells
Contain strands of cytoplasm continuous with that of next cell
Living cells
Companion cells
Lie next to sieve tubes
Thin walled with well defined nucleus
Cross wall present
Fibres and parenchyma as described above.
Sieve tubes transport manufactures food from leaves to all parts of body
Companion cells probably control the activities of sieve tubes.
Diagrams
Parenchyma
Epidermal
Epidermal Tissue – Root Hair
Epidermal Tissue – Stomata
Collenchyma
Sclerenchyma
Xylem
Phloem
Test Yourself
Question 1
The chief food making tissue of a plant is called
A Chlorenchyma
B Cortex
C Phloem
D Epidermis
E Xylem
Question 2
In a stem, collenchyma cells are mainly found near the
A xylem tissue
B epidermal tissue
C phloem tissue
D chlorenchyma tissue
E pith
Question 3
Tracheids differ from vessels because they are
A in the phloem
B much smaller
C thickened with lignin
D only found in softwood trees
E also found in sclerenchyma
Question 4
An example of a cell thickened with extra cellulose is
A collenchyma
B parenchyma
C tracheids
D vessels
E sclerenchyma
Question 5
Root hair cells are …..
A not living because the wall is lignified
B concerned with the entry of gases into the plant
C able to open and close due to uneven thickening
D waterproof to stop water diffusing into the soil
E concerned with absorbing water and mineral salts for the plant.
Question 6
Most of the photosynthesis in a plant occurs in the
A spongy mesophyll
B guard cells of the stoma
C green cortex cells
D phloem of the leaf vein
E palisade mesophyll
Question 7
Which of the following is NOT found in phloem tissue?
A parenchyma
B collenchyma
C sieve tubes
D companion cells
E fibres
Question 8
Which of the following is not a feature of sclerenchyma?
A contains fibres
B may contain stone cells
C lignified walls
D living tissue
E used for support
Question 9
Phloem tissue is...
A found in vascular bundles.
B made up entirely of non-living cells.
C a tissue which only conducts nutrients by diffusion.
D found in leaves only.
Question 10
The cells shown in the diagram on the right can be found in
A Bananas and pears
B pears and apples
C Apples and guavas
D Guavas and pears.
Improve your Skills
Question 1
Study the diagram below and answer the questions which follow on Plant Tissues.
1.1. Name the plant tissues represented by letters A, B, C and D. (4) 1.2. Explain how plant tissue labeled B is structurally suited for its function. (5) 1.3. Draw a simple diagram to show what the upper epidermis of a leaf would look
like. No labels required. (3)
Question 2
The photographs/diagrams below show various conducting cells / tissues of a plant.
2.1 Which photograph/diagram (A to D) represents a xylem tracheid?
Give a reason for your answer. (2)
2.2 Two cells are shown in diagram B.
Which labeled cell in diagram A is a cross section of one of these cells? (1)
2.3 Give the main function of cell type 4 in diagram D, and state how you were able to identify the cell. (2)
2.4 Of what substance is the cell wall of: a.) cell 1, and that of b.) cell 3 made.? (2)
Links
Bozeman summary - https://www.youtube.com/watch?v=zHp_voyo7MY