Ex2

Aim To prepare a temporary stained mount of a transverse section of dicot and monocot stem
and root to study various plant tissues.

Material Required
• Preserved material of sunflower root and stem
• Preserved or fresh material of maize root and stem,
• Microscope
• Sharp blade
• Slides
• Watch glass
• Coverslips
• Safranin (1gm in 100ml of 50% ethanol)
• Brush
• Glycerine
• Blotting paper

Procedure

Taking Sections
• Hold the dissected plant material between your index finger and thumb, while keeping the
edge of the razor perpendicular to the longitudinal axis of the plant. Slice it into thin sections.

Process Of Staining
• Pick 2 to 4 thin and good transverse sections. Shift it to a different watch glass holding
safranin stain.Rinse with water so as to wash off the excess strain.

Mounting
• On a clean slide, place a stained section in the middle of the slide, mounting water or
glycerine.
Precautionary Measures
• While dissecting the section, both the blade and the material should be supplied with
adequate water.
• While working with sections, use a brush.
• Gently place the coverslip in order to avoid air bubbles.
• Excess glycerine can be removed with filter paper.

T.S. of Dicot Stem – Sunflower Stem

Identification
• The epidermis has multicellular hairs.
• The hypodermis is collenchymatous.
• The xylem is endarch with the protoxylem being at the centre and the metaxylem being at the
periphery.
• Vascular bundles are open, collateral and conjoint.
• They are arranged in a ring-like manner.
• Pith is found at the centre.

T.S. of Dicot Root – Sunflower Root

Identification
▪ The epidermis shows the presence of unicellular hair
▪ Absence of hypodermis
▪ Radially arranged vascular bundles
▪ The number of phloem/xylem bundles is not more than 6
▪ The xylem is an exarch
▪ Absence or rare occurrence of pith

▪ T.S of monocot stem – Maize stem

▪ Vascular bundles
 ▪ Several scattered vascular bundles found in the ground tissue and are
closed type, collateral and conjoint
▪ Large vascular bundles in the center compared to vascular bundles at
the periphery
▪ They resemble an oval shape that is girdled by sclerenchymatous
bundle sheath

T.S of monocot root – Maize root

Identification
▪ Epidermis sees the presence of unicellular hair
▪ Absence of hypodermis
▪ Radially arranged vascular bundles
▪ 8 or more than 8 phloem and xylem bundles

Ex 3

Aim
To study by demonstrating the osmosis process by potato osmometer.

Material Required
A fresh large-sized potato tuber
20% sucrose solution
Beaker
Water
Scalpel/blade
Petri dish
A Bell pin needle that is labelled with a waterproof ink
PROCEDURE
The outer skin of potato is to be peeled off
 • From the mid-region of the tuber, scoop from the soft parenchyma, so as to form a tiny
cavity of a square or a circular shape. At the base, the cavity prepared should have a
minimum thickness.
• Fill up half the cavity with the freshly prepared 20% sugar solution. Into the cavity, fix a
pin in a way that the mark is in the same line with the layer of the sucrose solution.
• Set up the osmometer in a Petri dish/beaker that is filled with water in a way such that
75% of the potato osmometer is immersed in water
• The set up should remain uninterrupted for close to 1 hour.
• Notice the sugar solution in the osmometer towards the end of the experiment

Observation
After a period of time, within the osmoscope, the sugar solution rises and is seen coloured.

Conclusion
• An increase in the level of sucrose solution is observed in the osmometer. It is because of
the entrance of water due to endosmosis from the beaker.

Ex4

Aim

To study the phenomena of plasmolysis in epidermal peels of Rhoeo plant leaves in hypotonic
and hypertonic solutions using salt solution.
Materials Required
Needle.
Forceps.
Glass slides.
Watch glass.
Rhoeo leaf.
Coverslips.
Compound microscope.
Sodium chloride 5% solution.

Sodium chloride 0.1% solution. Procedure

• Take two clean and dried glass slides and place them on a table.
 • Select the fresh and cleaned Rhoeo leaves and place them on the watch glass.
• Fold the leaves in such a way that it tears from the lower side of the leaf.
• Extract two small fragments of a fine and transparent layer .
• Now set up the epidermal peels on each of the glass slides. add 1 to 2 drops of sodium
chloride 0.1% solution to one of the prepared slides. And add 1-2 drops of sodium
chloride 5% solution to the other prepared slide.
• Leave the prepared glass slide undisturbed for a few minutes.
• Now carefully place the slides under a compound microscope and observe the changes.

Observation
After a period of 30 minutes, we can notice that cells placed in the sodium chloride 0.1% solution
seem to be turgid and the cells placed in the sodium chloride 5% solution seem to be shrunk with
the loss of water and it exhibits the process of plasmolysis.

Precautions

The part of the Rhoeo leaf that needs to be extracted for the experiment is the epidermal peel from
the lower surface

Care needs to be taken to ensure that the peel is moist and not dry.

Ex5

Aim
To study the pattern and distribution of stomata in both the upper and lower leaf surfaces.

Material Required
• Blade
• Forceps
• Dropper
• Glycerine
• Cover slip
• Watch glass
• Glass Slide
• Needle and brush
• Safranin solution
• Four O’clock plant
• Compound microscope
Procedure
• One fresh leaf from a four-o’clock plant is used in this experiment
• Slit the leaf in an oblique manner
• With the help of forceps, peel a section from the upper surface of the leaf and lower surface
seperately.
• With the help of a dropper, add few drops of safranin solution into both the watch glasses
• Now place cleared glass slides on each of the peels one at a time with the help of a brush
• Prepare slide for observation.
• Examine each of the glass slides under the microscope

Observation And Conclusion

The section of leaf plucked from the four-o’clock plant shows that the number of stomata is much
more in the lower epidermis while a few are found in the upper epidermis of the leaf.

Precautions
• Avoid leaf curling
• Gently place the cover slip on the slide to avoid air bubbles.

Ex6.

Aim
Compare the rates of transpiration in the upper and the lower surface of leaves.

Material Required

A potted plant

Forceps

Filter paper strips

Wire gauze

3% cobalt chloride solution

Petri Dish

Binder clips

Glass Slide
Procedure

Into the Petri dish, pour the cobalt chloride solution

Dip a few strips of filter paper into the solution

Allow the strips to stay in the solution for a few minutes, watch them turn pink in colour

With the help of forceps, separate the strips

Allow the strips to dry by placing them on the wire gauze

Upon drying, the strips turn blue in colour

Pluck a healthy leaf from the potted plant, clean it to remove excess droplets with the help of filter
paper

After drying on the wire gauze, set the dried strips one on the upper surface of the leaf and one on
the lower surface.

Now place 2 glass slides on each surface of the leaf, i.e., the upper surface and lower surface.

With the help of binder clips, secure the slides.

Observe and make note of the time that is consumed by the paper to switch its colour from blue to
pink.

Observation

Through the experiment carried out, it is observed that the amount of time taken for the colour
change of the cobalt chloride paper from blue to pink on the lower surface of the leaf is lesser than
the upper leaf surface.

Conclusion

The rapid switch of the colour of the cobalt chloride paper on the lower surfaces depicts that rate of
loss of water vapour is higher on the lower surface than the upper surface.
•