Useful for pharmacy students

1. STUDY OF CELL WALL COMPOSITION AND
CELL INCLUSIONS
Dr.U.Srinivasa, M. Pharm., M.Phil., Ph.D.
Professor and Head,
Dept. of Pharmacognosy
Srinivas college of pharmacy, Mangalore.
Email. usreenivas1966@rediffmail.com

2. • Cell wall constituents:
• The cell wall of plant cell composed of cellulose, lignin, cutin,
suberin, mucilage etc.
• Cellulose:
• It is the main constituent of plant cell wall, chemically a
polysaccharide consisting of long straight unbranching chains
of -D-Glucose residue formed by 1-4 linkage.β
• Test: Place a T.L.S of petiole of datura on glass slide. Add a
few drops of iodine solution. After 3 minutes drain off excess
iodine and add 2 drops of conc. sulphuric acid. Remove excess
of acid. Add 2 drops of glycerine. Place cover slip and observe
under the microscope.
• Observation: Observe the slide under the low power
objective. The cellular wall of rectangular parenchyma cell
takes up blue colour.

3. • Lignin:
• It is present in the middle lamella of the woody
tissue and other thickened cells. Chemically, it is
complex phenylpropanoid polymer varying
according to its source.
• Test: Place a pinch of cassia powder on a slide. Add
few drops of phloroglucinol and equal volumes of
conc. HCl. After 3-5 minutes transfer a portion of
staining powder into another slide and add few
drops of chloral hydrate.
• Observation: The spindle shaped fibres and
rectangular sclereids take pink colour due to the
presence of lignin.

4. • Cutin:
• It is the characteristic constituent of the cuticle. It is
condensed or oxygenated form of fatty acids known
as cutinogenic acids which are relatively
impermeable to water and gases.
• Test: Take a small piece of epidermal scrapping of
ephedra stem. Place it on a glass slide and add few
drops of caustic potash. Transfer scrapping to
another slide and mount in chloral hydrate as
above.
• Observation:
• The epidermal cell which are covered by thick
cuticle take up bright yellow colour.

5. • Suberin:
• It is present in the walls of cork cells rendering them
impervious to water. It is a complex mixture of
oxidation and condensation of fatty acids
(suberogenic acid).
• Test: Scrap a small piece of outer cork layer of fresh
rhizome of ginger. Place it on a slide, add caustic
potash solution and finally transfer the material to
another slide. Mount with chloral hydrate solution
and observe under microscope.
• Observation: The cork cells take up yellowish
brown colour due to the presence of suberin.

6. • Mucilage:
• Mucilage is a polysaccharide complex of sugar and
uronic acids usually formed from the cell wall. They
are insoluble in alcohol but swells or dissolve in
water.
• Test: Take a pinch of isapgol powder in a slide; add
a few drops of rhuthenium red. Observe under the
microscope.
• Observation:
• The epidermal cells swell up and take pink colour
due to mucilage.

7. • Cell Inclusions:
• They are living and non living cell inclusions (ergastic
substances). Non living cell inclusions are further
classified into reserve foods, excretory and secretary
products
• Starch grains:
• Starch is present in different parts of the plant in the
form of granules of varying size. Chemically starches
are polysaccharides containing amylopectin and β
amylase. Starch of pharmaceutical interest obtained
from maize, rice, wheat and potato.
• Test: Potato powder is taken and is add iodine
solution , starch stains blue colour. It is then observe
under the microscope (objective 45x)

8. • Volatile Oil:
• Occur as droplets in plant cells. It is soluble in alcohol
and sparingly soluble in water.
• Test: Take a section of clove add Sudan red oil
gland takes a red colour.
• Calcium oxalate:
• These are considered excretory products of plant
metabolism
• Test: The liquorice powder or senna powder is
taken and chloral hydrate is added, it is heated and
observed under microscope.

9. • Cluster crystals
• Test: To peeled datura leaf or rhubarb powder,
water is added and observed under microscope.
Acicular raphides
• Test: To Squill powder water is added and
observed under microscope
• Calcium Carbonate:
• Test: A longitudinal section of vasaka petiole is
taken, and observed under the microscope. Sandy
balls
• Test: Water is added to belladona powder and is
observed under microscope, Sandy balls

10. • Cluster crystals
• Test: To peeled datura leaf or rhubarb powder,
water is added and observed under microscope.
Acicular raphides
• Test: To Squill powder water is added and
observed under microscope
• Calcium Carbonate:
• Test: A longitudinal section of vasaka petiole is
taken, and observed under the microscope. Sandy
balls
• Test: Water is added to belladona powder and is
observed under microscope, Sandy balls