1. Plant Cell Types and Tissues
Exercise 5
Plant Cell Types and Tissues

2. Tissue – group of cells that perform a specific function
2 kinds of tissues (state of development):
1. Meristematic tissues/ meristerms
- responsible for the production of new cells
2. Permanent tissues
- perform specific functions

3. Kinds of meristems based on their position or location:
1. Apical meristem – responsible for the increase in length of stems or roots
- at tips or apices of stems and roots
- with very small or no vacuole at all
- very thin-walled and isodiametric
Includes:
Protoderm
Ground meristem
Procambium

4. 2. Lateral meristem 3. Intercalary meristem – at bases of young leaves and internodes - for further lengthening of stems and leaves far away from the tips of stems

5. Kinds of Permanent Tissues:
1. Simple permanent tissues - consist only of one kind of cell a. Epidermis – outermost tissue of leaves, stems and roots of all monocots and herbaceous dicot - has a layer of cuticle made up of waxy substance called cutin to prevent excessive evaporation of water - uniseriate when young, multiseriate when old

6. b. Parenchyma – uniformly thin-walled
Function: for food storage
Examples: cassava pith, tomato fruit pulp, Spanish flag petiole

7. c. Collenchyma – with unevenly thickened walls
- function: for strengthening & support and sometimes for storage
- examples: lotus petiole, celery petiole, coleus petiole

8. d. Sclerenchyma – with heavily thickened walls because of the presence of lignin
function: for strengthening & support
Examples: mungbean seed coat, peanut pericarp, pineapple leaf

9. e. Cork – outermost tissue of leaves and roots of woody dicot plants
- function: for protection

10. 2. Complex Permanent Tissue
1. Phloem – conducts dissolved organic food materials
Sieve tubes
Companion cells
Arranged end to end
Shorter, narrower, vertically elongated
Denucleated when matured
Nucleated even when matured
2. Xylem – conducts water
Tracheids – without perforations
Vessel elements – with perforations

11. Accessory cells – participate in osmotic changes involved in movements of the guard cells

12. Closed Stomata
Open Stomata

13. Exercise 6 Absorption
Tap Root
Fibrous Root

14. Modification & function
Specialized Roots
Specimen
Modification & function
Camote
Enlarged fleshy root for food storage
Radish
Carrot
Rhizophora
Brace roots for support
Pandan
Prop roots for support
*brace roots – aerial roots arising from the main stem which penetrates the ground
*prop roots – aerial roots arising from the branches which penetrate the ground

15. Exercise 7 Transport & Nutrition
Origin of the stem: from the epicotyl and partly from the hypocotyl of the embryo
Shoot – a stem with leaves
Shoot system – all the stems and leaves of a plant

16. General Features of the Stem:
1. Node – where leaves, branches & buds arise 2. Internode – portion between 2 consecutive nodes 3. Leaf sheath - in some monocotyledons (Poaceae/ Gramineae/ grass family), a distinct petiole is lacking. Instead, the blade is supported by a flattened structure called the leaf sheath, which clasps the stem.

17. 4. Petiole – or leaf stalk - holds the blade upright 5
4. Petiole – or leaf stalk - holds the blade upright 5. Leaf scar – mark left on the stem by a fallen leaf 6. Bundle scar – cut end of vascular bundles seen within each leaf scar 7. Leaf axil – angle formed by the leaf stalk and the stem

18. 8. Axillary bud – located at the leaf axil 9
8. Axillary bud – located at the leaf axil 9. Terminal bud – located at the tip of the stem 10. Bud scale – protective scale that covers the bud 11. Lenticels – tiny raised pores on dicot stems for gaseous exchange

19. Modified Stems: Plant Specimen Modification Fern plant, Ginger
Rhizome for food storage
Gabi
Corm
Potato (Solanum tuberosum)
with “eyes” = buds
Tuber for reproduction
Bermuda Grass
Runner/Stolon
Bougainvillea
Thorn for protection
Dilang-baka
Cladophyll
Vine
Tendril
Cycas
Spines for protection

20. Exer 7 Leaf Important Terms:
1. Phyllotaxy – system of leaf arrangement on the stem:
a. Alternate or spiral – only 1 leaf develops at each node
b. Opposite – 2 leaves develop opposite each other at a node
c. Whorled – 3 or more leaves develop equidistantly around the node

21. 2. Blade or lamina – thin, flattened, green structure 3
2. Blade or lamina – thin, flattened, green structure 3. Leaf stalk or petiole – holds the blade upright; to provide maximum exposure *sessile – leaf without petiole 4. Stipules – a pair of outgrowths at base of some dicotyledonous leaves *exstipulate – without stipules

22. Petiolule – stalk of each leaflet
Stipels – outgrowths in pairs found at the base of petiolule
Rachis – continuation of the petiole

23. 5. Nature of leaf blade Simple leaf – blade consists of only 1 piece
Compound leaf – blade is divided into separate segments called leaflets or pinna

24. 6. Venation – arrangement of vein of a leaf blade
Netted or reticulate venation – veins branch profusely and form a network over the blade; commonly found in dicot leaves
Parallel venation – veins do not form a network; commonly found in monocot leaves