Activity 2 Plant Cells and Tissues

 

Department of Education Region IX, Zamboanga Peninsula REGIONAL SCIENCE HIGH SCHOOL-IX Malasiga, San Roque, Zamboanga City

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 ACTIVITY 2 Observing Plant Cells and Tissues

I. Introduction: Cell is defined as the structural unit of all life forms such as plants. Plant cells are bounded by a plasma membrane that is composed of a phospholipid bilayer with embedded proteins. Everything inside the plasma membrane is called the protoplasm.  A tissue is a group of cells having a common function or structure. Plant tissues of the vascular plants are often categorized into three broad classes: ground, vascular and dermal. A concept map below summarizes these 3 types:

Plant Tissues

Ground Tissues

Vascular Tissues

Dermal Tissues

Parenchyma

Xylem

Epidermis

Collenchyma

Phloem

Periderm

Sclerenchyma

II. Objectives:  At the end of the session, the students should be able to: 1.  Identify anatomical and physiological features of a plant cell and its organelles. 2.  Differentiate the types of plant tissues according to anatomical and physiological features. III. Materials: Hydrilla Rheo discolor Okra Carabao grass

Coleus blumei  stem  stem  Allium cepa bulb Bougainvillea stem Microscope Razor blade

 

 

Cover slip Glass slide Toluidine blue

Dropper Iodine solution

IV. Methods:  Methods:   A. Plant Cell 1.  Mount a fresh leaf of Hydrilla  in  in a glass slide. Look for the dark structure that is usually located at the center. This is one of the cellular organelles that are visible under a compound microscope. A structure that gives rigidity to the cell is called the cell wall, a layer of the plant cell that is secreted outside the plasma membrane. Everything inside the plasma membrane but not including the nucleus is called the cytoplasm. Draw and label these visible parts in Fig. 1. 2.  Differentiate other cell organelles that are not visible under the compound microscope in terms of their anatomical and physiological features. Complete Table 1. 3.  Prepare epidermal peels of the lower leaf of the Rheo discolor  by   by scraping it very thinly with the use of a razor blade. Cover it with a cover slip. Examine the slide under the microscope.  Answer related questions below. Write your answers on the space provided in the answer sheet. a.  What do you call these number of specialized epidermal cells consisting of 2 guard cells? b.  Where can you find the greatest number of specialized epidermal cells  –  on the upper epidermis or lower epidermis? Describe its adaptive significance. 4.  Draw and label the specialized epidermal cells in Fig. 2. 5.  Observe the trichomes of various plant organs ( Rheo discolor leaf and okra fruit). Peel the epidermal tissue bearing the trichomes. Trichomes are cellular appendages that grow from the epidermal cells. 6.  Place in a separate glass slides and add a drop of water. The material may be stained with Toluidine blue. Carefully draw the various trichome types on the space provided in Fig. 3 and 4. B. Plant Tissues B.1. Ground Tissues Ground tissue is that occurring inside the epidermis but not part of the vascular tissue. The 3 cell types include parenchyma, collenchyma, and sclerenchyma. 1.  Examine a prepared slide of Hibiscus rosa-sinensis   stem, x.s. under HPO. Locate these ground tissues and draw and label in Fig. 5. 2.  Differentiate these types of ground tissues in terms of its anatomical and physiological feature. Complete Table 2. B.2. Vascular Tissues  Vascular tissues are consist of cells specialized for conduction, namely, xylem and phloem. Xylem is the water-conducting tissue usually found towards the pith. It is composed of tracheids and vessels. The phloem is a food-conducting tissue, usually found outside the xylem region. The bundle cap, if present, forms the outermost part of the phloem region. It may be collenchymatous or sclerenchymatous.

 

1.  Examine again the prepared slide of Hibiscus rosa-sinensis   stem, x.s. under HPO. Locate these vascular tissues and draw and label in Fig. 6. 2.  Differentiate these types of vascular tissues in terms of its anatomical and physiological features. Complete Table 3. B.3. Dermal Tissues  Tissues  Dermal tissues make up the outermost region of the plant and functions in mechanical protection of inner tissues and inhibition of water loss. It is consist of epidermis or in woody plants, the periderm. 1.  Examine again the prepared slide of Hibiscus rosa-sinensis   stem, x.s. under HPO. Locate these dermal tissues and draw and label in Fig. 7. 2.  Differentiate these types of dermal tissues in terms of its anatomical and physiological features. Complete Table 4. B.4. Modified Stems 1.  Examine the various modified stems such as the following: carabao grass, bougainvillea, and onion bulb. Complete Table 5 for their modifications. 2.  Prepare a longitudinal section of mayana shoot apex and examine under LPO and identify the anatomical structures that can be seen. Draw and label in Fig. 8.

  3. Prepare a free-hand cut of thetheinternodes in structures mayana stem. Illustrate a detailed portion of thecross cross section section and label parts of the that can be seen in Fig. 9. 4.  Prepare a free-hand section cut of the carabao grass. Illustrate a detailed portion of the cross section and label the parts of the structures that can be seen in Fig. 10. 5.  Prepare a free-hand section cut of the onion bulb. Illustrate a detailed portion of the cross section and label the parts of the structures that can be seen in Fig. 11. C. Prepared Slides 1.  Observe 4-5 prepared slides of plants under LPO and HPO. Draw and label the parts that can be seen in Fig. 12, 13, 14 and 15, respectively.

 

 V. Results and Discussion: Discussion:  A.  Plant Cell

Fig. 1. Visible Parts of a Plant Cell Table 1. Anatomical and Physiological Features of some Cell Organelles

1. 2. 3. 4. 5.

Cell Organelle mitochondria nucleus chloroplast large central vacuole rough endoplasmic reticulum

Anatomical Feature

Physiological Feature

6. golgimembrane bodies 7. cell 8. cytoplasm 9. centriole 10. smooth endoplasmic reticulum a.  What do you call these specialized epidermal cells consisting of 2 guard cells?  ______________________________________________  ______________________ ___________________________________________________ ____________________________  _   ______________________________________________  ______________________ ___________________________________________________ ____________________________  _   ______________________________________________  ______________________ ___________________________________________________ ___________________________ b.  Where can you find the greatest number of specialized epidermal cells  –  on the upper epidermis or lower epidermis? Describe its adaptive significance.  ______________________________________________  ______________________ ___________________________________________________ ____________________________  _   ______________________________________________  ______________________ _________________________________________ ____________________________  ___________   ______________________________________________  ______________________ ___________________________________________________ ____________________________ _

Fig. 2. Specialized Epidermal Cell

 

 

Fig. 3.Rheo discolor

Fig. 4. Okra

Different Types of Trichomes Related Questions: 1. Discuss the significance of examining anatomical features.  ______________________ ___________________________________________________  ______________________________________________ ____________________________________  _________   ______________________________________________  ______________________ ___________________________________________________ ____________________________________  _________   ______________________________________  ______________________ __________________________________________ __________________________________________ ________________ 2. Enumerate the functions of trichomes.  ______________________ ___________________________________________________  ______________________________________________ ____________________________________  _________   ______________________________________________  ______________________ ___________________________________________________ ____________________________________  _________   ______________________________________________  ______________________ ___________________________________________________ __________________________________ _______ 3. Is the trichome anatomy the same from organ to organ or does it vary? What might be the adaptive significance of trichomes?  ______________________ _____________________________________  ______________________________________________ ____________________________________  _______________________   ______________________________________________  ______________________ ___________________________________________________ ____________________________________  _________   ______________________________________________  ______________________ ___________________________________________________ __________________________________ _______

B. Plant Tissues  Tissues 

Fig. 5. Ground Tissue

 

Table 2. Anatomical and Physiological Features of Ground Tissues Ground Tissues 1. parenchyma 2. collenchyma 3. sclerenchyma

Anatomical Features

Physiological Features

Fig. 6. Vascular Tissue Table 3. Anatomical and Physiological Features of Vascular Tissues  Vascular Tissues

Anatomical Features

Physiological Features

1. xylem 2. phloem

Fig. 7. Dermal Tissues Table 4. Anatomical and Physiological Features of Dermal Tissues Dermal Tissues 1. epidermis 2. periderm

Anatomical Features

Physiological Features

Modified Parts

Function

Table 5. Modified Stems Specimen 1. grass 2. Carabao Bougainvillea 3. Onion bulb

 

 

Fig. 8. Mayana shoot apex, l.s.

Fig. 9. Internode of Mayana Stem

Fig. 10. Carabao grass

Fig. 11. Onion bulb

 

 

Fig. 12. Prepared Slide 1

Fig. 13. Prepared Slide 2

Fig. 14. Prepared Slide 3

Fig. 15. Prepared Slide 4

 

Related Questions: 1. What are the similarities of parenchyma and collenchyma? How do they differ from sclerenchyma? sclerenchym a?  ______________________ ___________________________________________________  ______________________________________________ ____________________________________  _________   ______________________________________________  ______________________ ___________________________________________________ ____________________________________  _________   _____________________________________________  ____________________ _________________________________________________ ___________________________________ ___________ 2. Differentiate specialized types of epidermal cells.  ______________________________________________  ______________________ ___________________________________________________ ____________________________________  _________   ______________________ _____________________________________  ______________________________________________ ____________________________________  _______________________   ______________________________________________  ______________________ ___________________________________________________ __________________________________ _______  VI. Conclusion: Conclusion: