Anatomy of a dicot leaf

Procedure on how to cut a dicot leaf

1. Anatomy of a Dicot Leaf External and Internal Structure

2. Objectives: 1. Name the external features of a dicot leaf and give its function. 2. Label the internal structure of the dicot leaf. 3. Examine and draw the components of the internal structure of a Ficus benghalensis

3. Criteria for : Activity 3 Neatness-3 Content-7 Accuracy-10 total-20 pts

4. Apparatuses: Specimens: Microscope Glass slides Razor blades Short Bond paper Ficus benghalensi s leaf Materials:

5. The External Anatomy of a Dicot Leaf Parts and functions

6. A typical leaf of a  dicotyledonous  plant consists of  two main parts : the blade the petiole Parts and Functions Leaves the powerhouse of plants the major site of food production for the plant structures within a leaf convert the energy in sunlight into chemical energy that the plant can use as food. Chlorophyll is the molecule in leaves that uses the energy in sunlight to turn water (H 2 O) and carbon dioxide gas (CO 2 ) into sugar and oxygen gas (O 2 ). This process is called photosynthesis.

7. Leaf Blade Expanded part of a leaf thin and supported by a network of veins Inside the blade: Veins -like wrinkles or pipes running along the blade Midrib -the central vein

8. Margin the rim or final limit of the blade - comes in many sizes and shapes (see image at the right) Apex - the outer end of a leaf; the end that is opposite the petiole. Parts and Functions

9. The Petiole vary considerably and can be long, short, rounded or flat Some leaves have no petioles in which case they are said to be sessile At the base of the petiole in many leaves are small leaf-like structures called  stipules Between the petiole and the stem is an axial bud

10. The Internal Anatomy of a Dicot Leaf

11. Epidermis Upper epidermis -wraps around the leaf and is continuous with the Lower Epidermis -layer of closely packed cell Lower epidermis -similar to upper epidermis but it has many pores or stomates Parts and Functions

12. Parts and Functions Mesophyll -composed of two layers: palisade parenchyma and spongy parenchyma -between the upper and lower epidermis -composed of collenchyma , veins, a certain amount of fibrous tissue

13. Parts and Functions Palisade parenchyma -layer of evenly-space cylindrical cells whose long axes are at the right angles to the upper epidermis -site of photosynthesis where there are abundant of chloroplasts Spongy parenchyma -lower portion of the mesophyll -more loose zone of irregularly shaped cells and large spaces

14. Veins -cylindrical strands of vascular tissue and occur in mesophyll Xylem cells -thick, angular, red stained walls and absence of cell contents Phloem cells -thinned walled, usually of smaller diameter Bundle sheath cells -large, thin walled parenchyma cells that encircle and radiate out form the vein Parts and Functions

15.   Stoma – opening between the guard cells; allows for gas exchange and some water  Guard cells – surround the stoma; control the opening and closing of the stoma Parts and Functions

16. Activities Learning Checkpoints

17. Activity 1:Name Me Directions: Label the parts of the leaf and identify its function.

18. Activity 2: Fill the Gaps Click this website http://nhscience.lonestar.edu/biol/biolab/leaf.htm and answer correctly the given exercise.

19. Activity 3: “ Examine My Parts “ Procedure Cut thinly a cross section of a Ficus benghalensis leaf using a razor blade. Place in clean glass slide. Examine under the microscope. Draw and label the parts in a short bondpaper .

20. References : http://nhscience.lonestar.edu/biol/biolab/leaf.htm http://www.botany.uwc.ac.za/ecotree/leaves/leaftypea.htm http://images.tutorvista.com/content/feed/tvcs/Internal20Structure20of20le af.jpg http://www.botanical-online.com/lahojaangles.htm#CONTORN