Mar 12, 2014 - Regular shape. ⢠Actively dividing â. Mitosis. ⢠Produce .... The photographs/diagrams below show v
PLANT TISSUES 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
12 MARCH 2014
TISSUE Meristematic
Epidermis
LOCATION 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 Outer covering of roots, stems and leaves
Forms bulk of roots, stems, leaves and flowers.
Chlorenchyma
In upper layers of leaves and stems Palisade and spongy mesophyll of leaves
Collenchyma
In epidermis of young stems
Parenchyma
STRUCTURE Thin willed Large nucleus No intercellular spaces Regular shape
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 Irregularly shaped round, oval Thin-walled, large vacuole Large intercellular spaces Lack chloroplasts Parenchyma tissue with chloroplasts Thin-walled, irregularly shaped with intercellular spaces. Elongated upper layer – palisade layer Regular shape No intercellular spaces Corners of cells are thickened
FUNCTION Actively dividing – Mitosis Produce new cells for Growth in length and width Replace worn-out or damaged tissue Differentiate into different types of tissue 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.
Packing tissue Stores food as starch or sugars Intercellular airspaces allow water and gases to pass through. Manufactures food y photosynthesis.
Give support and strength to aboveground parts
Sclerenchyma
Xylem
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 Within veins of leaves, vascular bundles of stems and stele of roots
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.
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
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. 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. 1.2. 1.3.
Name the plant tissues represented by letters A, B, C and D. Explain how plant tissue labeled B is structurally suited for its function. Draw a simple diagram to show what the upper epidermis of a leaf would look like. No labels required.
(4) (5) (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. Of what substance is the cell wall of: a.) cell 1, and that of b.) cell 3 made.?
