Experiment 1: 

Study Of Pollen Germination on a slide  

Our Objective
Our aim is to study pollen germination on a slide.
Lab Procedure
 Prepare the pollen germination medium by dissolving 10 grams sucrose, 10
milligrams boric acid, 30 milligrams magnesium sulphate and 20 milligrams
potassium nitrate in 100ml of distilled water.
 Using a glass rod, stir the solution to mix it well.
 Using a dropper, take some nutrient solution and put two drops on a clean
glass slide.
 Take a mature flower and dust a few pollen grains from its stamen on to
the drop on the slide.
 After 5 minutes, place the glass slide on the stage of the compound
microscope.
 Observe the slide through the microscope regularly for about half an hour.
 
Observations
The pollen grain is uninucleate (has one nucleus) in the beginning. At the time of liberation,
it becomes 2 celled, with a small generative cell and a vegetative cell. In the nutrient
medium, the pollen grain germinates. The tube cell enlarges and comes out of the pollen
grain through one of the germ pores to form a pollen tube. The tube nucleus descends to
the tip of the pollen tube. The generative cell also passes into it. It soon divides into two
male gametes.
Study of Physical Properties of Soil:

Experiment 2: Study Of Study of Physical Properties of Soil (Texture, pH, Moisture

Content, Water Holding Capacity Of The Salt)  

Our Objective
Our aim is to Study of Physical Properties of Soil

Theory
Soil is the upper humus, containing a layer of the earth, consisting of rock and mineral
particles mixed with decayed organic matter.  Soil sustains plant life and contains numerous
living organisms. Soil, along with air and water, is one of the three most important natural
resources, which we cannot live without.  A productive soil contains approximately 46%
mineral matter, 4% organic matter, 25 % water and 25% air. An approximate composition of
soil shown below 

Physical characteristics of soil.

The physical characteristics of a soil are due to the size of its soil particles.  Soils are
classified according to their particle size as follows: 

Texture of Soil
Soil texture is an important physical characteristic of soil which is used in both the field and
laboratory to determine classes for soils based on their physical texture. The soil texture
depends upon the proportion of the constituent solid particles of different sizes. The terms
sand, silt, and clay refer to particle size; sand is the largest and clay is the smallest. The size
of sand particles is 0.05–2 mm, silt particles are 0.002–0.05 mm, and clay is smaller than
0.002 mm. The term loam refers to a soil with a combination of sand, silt, and clay sized
particles.  Each texture corresponds to specific percentages of sand, silt, or clay. The soil
texture triangle is a tool used to visualise and understand the meaning of soil texture
names. 
If we know the sand, silt, and clay percentages of a soil, then the textural class can be
identified from the textural triangle. Say for an example soil consists of 12% clay, 55% sand
and 31% silt, we will see how to determine the textural class of the soil. Here, the sample
soil has 12% clay, so draw a line corresponding to percent clay. Similarly draw the lines for
percent sand (55%) and percent silt (31%). The lines which intersect indicate the soil type
we have. From the above sample, soil consists of 12% clay, 55% sand, and 31% silt; hence

the soil type is sandy loam. 

pH of Soil
The chemical property of the soil depends upon the presence of different types of nutrients
and pH of the soil. The soil pH is an indication of acidity or alkalinity of soils. The soil pH is
important in determining the availability of soil minerals.  Different plants have differing
optimum soil pH requirements. The majority of plants prefer a pH of around 6 to 7, which is
very slightly acidic.

Water Holding Capacity of Soil

One of the main functions of soil is to retain water and make it available for the plant to
access.  All of the water in the soil is not available to plants. The amount of water available
to plants is therefore determined by the number and size of the soil’s pore spaces. Water
holding capacity of the soil is the amount of water held by the capillary spaces of the soil
after the percolation of gravitational water into the deeper layers.  Fine sandy loam, silt
loam and silty clay loam soil store the largest amount of water, whereas sand, loamy sand
and sandy loam have limited water storage capacity.

1. To Study pH of Different Types of Soil

Procedure:

 Take roadside soil from the watch glass and dissolve it into the beaker containing
water to make soil solution.
 Similarly, repeat the same procedure for other soil samples.
 Take a funnel, place a filter paper in it and keep it on a test tube.
 Take roadside soil solution and filter the solution through the filter paper and collect
the filtrates in a test tube.
 Repeat the same procedure for other samples with fresh filter papers.
 The soil solution is now ready for testing ph.
Using pH Paper
 Take a pH paper booklet.
 Tear pH paper strips from the booklet and place 4 strips on the tile.
 Using a dropper, take some roadside soil solution from the test tube.
 Put 1 to 2 drops of solution on the first pH strip on the tile.
 Using fresh droppers, do the same procedure for garden soil, humus rich and
riverside soil.
 Wait for some time for the pH paper strip to dry.
 Note the colour and compare with the colour chart given on the broad range
indicator paper and get a rough estimate of pH of the sample solutions.
Observations:
We can observe that the roadside soil has pH 7, garden soil and humus rich soil have ph 6
and riverside soil has pH 8.

Study Moisture Content of Soil

Lab Procedure:
 Take watch glass containing garden soil and put it into a crucible/china dish.
 Weigh the crucible/ china dish with soil sample on a weighing balance.
 Take crucible/ china dish and place it over the Bunsen burner.
 Heat the soil for some time till the soil becomes dry.
 Weigh the crucible/ china dish again to record the weight of dry soil.
 Take watch glass containing roadside soil and put it into a crucible.
 Weigh the crucible/ china dish with soil sample on a weighing balance.
 Take crucible/ and place it over the Bunsen burner.
 Heat the soil for china dish some time till the soil becomes dry.
 Weigh the crucible/ china dish again to record the weight of dry soil.
Observation
Record the initial and final weights of each sample and the difference between initial and
final weights in the form of a table.
Conclusion
Garden soil shows higher difference between initial and final weight indicating higher
moisture content in the garden soil than the roadside soil.
Texture of Soil
Aim To collect and study soil from at least two different sites and study them for texture to correlate
with the kinds of plants found in them.

Texture of Soil

Materials required

(1) Hand lens,

(2) Sieves with meshes of different sizes,

(3) Soil samples collected from different sites,

(4) White sheets/ plain papers.

Procedure

There are two methods to study the texture of soil.

(a) Study by hand lens and in between fingers

1. Take little soil in hand and feel it, and also squeeze it in between the thumb and fingers. (Dry soil
as well as moist soil.)

2. Note your observations and compare/tally it with the information given in the table. And note it
in your practical record file.

3. Take little soil on the white paper. Observe it under the hand lens. (Dry soil as well as moist soil.)
Note your observations and compare it with the information given in the Table A.

Table A:

Texture of Soil (A physical property)

S.No. Texture Soil as felt between thumb and fingers

1 Sand (a) Individual dry soil grains may be seen or felt.
(b) They form a cast when moist soil is squeezed
2 Sandy Loam (a)Individual soil grains can be seen and felt.
Loam
(b) They form a cast but fall apart when dry soil
is squeezed.
(c) Moist soil forms a cast that does not break.
3 Loam (a) Gentle and gritty feeling.
(b) When dry soil is squeezed, forms a cast
bearing a careful handling.
(c) Moist soil cast is easily handled without
breaking.
4 Silt Loam (a) Soil appears cloddy or lumpy with soft feeling.
(b) Dry and moist soil forms cast that can be
easily handled without breaking it.
(c) If moist soil is squeezed it does not form
ribbons
 5 Clay Loam (a) Hard and dry soil breaks into lumps or clods.
loam
(b) Moist soil when pinched, it forms thin ribbon
which breaks readily.
(c) Moist soil forms cast that can bear much
handling

6 Clay (a) Dry soil forms very hard lumps or clods.

(b) Wet soil is sticky.
(c) Moist soil forms long flexible ribbon when it is
squeezed

Observation table

S. No Source/Name of soil Observation by Feeling of soil Inference

hand lens particles in-
between fingers
1
2

Conclusion

Study by sieving method (standard method)

1. Take soil samples and separately pass them/sieve them through sieves with meshes (nets) of
different sizes.

2. Start with big/maximum mesh size. Sieve the soils over a white sheet of paper.

3. Sieve out/separate out the soil particles of different sizes with the help of sieves on separate
papers. Note the name of soil (parent soil). Repeat this process for all samples of soil.

4. Find out the relative proportion of each fraction. Note it.

Study the texture/tally it from table:

S. No. Soil particle Size (diameter in mm) of particle

1 Gravel 2.00 mm and more
2 Coarse Sand 2 mm – 0.20 mm
3 Fine Sand 0.2 mm – 0.02 mm
4 Silt 0.2 mm – 0.002 mm
5 Clay Below 0.002 mm
S. No. Soil type Main particles Percentage
1. Sandy Soil Sand 85%–90% sand + 15%
clay or silt or both
2 Sandy Loam Sand, Loam 50%-90%
3 Loamy Soil All particles in equal All particles in equal
amounts amounts
4 Clay ,Loam Clay, Loam 50-55%
5 Silt Silt, Other particles 55%
6 Clay Clay 65%

Observations

S. No. Sample of soil Main particles Inference

1
2

Conclusions
Study of gamete development
Aim: To study and identify the stages of gamete development through permanent slide

Procedure

(i) Clean the slide and microscope’s eye and objective lenses with the help of lens cleaning paper
using any cleaning fluid.

(ii) Place the slide on the stage of the microscope and observe first under lower magnification and
then in higher magnification. Observe various stages of gamete development.

(iii) Record your observations in the notebook and draw labelled diagrams.

Observation

T.S. of testis

T.S. of mammalian testis Seminiferous tubule Spermatozoa Germinal Epithelium Spermatogonia

(i) Testis is enclosed within a thick fibrous tissue called tunica albuginea

(ii) large number of seminiferous tubules are observed under lower magnification. Observe a
complete tubule in higher magnification and view various stages of gamete development from
periphery towards lumen and identify the following types of cells namely, Germinal epithelium,
Spermatogonial cells, Primary spermatocytes, Secondary spermatocytes, Spermatids and
Spermatozoa.

Pyramid shaped Sertoli cells are found in between the germinal cells

(ii)In T.S. of testis the space between tubules are filled with blood vessels and a specific cell type
called Leydig's cell or Interstitial cells.
T.S. of Ovary

(i) In the section of ovary, there is a mass of tissue lined with germinal epithelium Inside which is
present the primary/secondary oocyte , which is a cell surrounded by one to several layers of
follicular cells. As the follicle matures, the number of surrounding follicular cell layer increases

(ii) In the later stage of follicular development a cavity called antrum appears.

(iii) The cavity gets further enlarged and the follicle grows bigger. This is the stage of Graafian follicle
ready to release the /secondary oocyte (ovulation).

(iv) In the next stage, Corpus luteum, and/or Corpus albicans is observed, which differ from each
other and also from Graafian follicle in their features.
Study of blastula

Aim To study blastula stage of embryonic development in mammals through permanent slide

Procedure

Observe the slide under lower magnification of the microscope. In case of

chart/models/photographs, note the feature of blastula in your practical record and draw labelled
diagram.

Observation

In transverse section, the blastula appears as a sphere with a cavity, called blastocoel within it
Notice an outer layer of blastomeres called trophoblasts. A cellular mass, adhered to the trophoblast
is present on one end of the blastula. It is called inner cell mass.

The cells of trophoblast give rise to the placenta while the inner cell mass gives rise to the embryo
Meiosis in Onion Bud Cell or Grasshopper Testis through Permanent Slides

Aim
To observe the stages of meiosis on onion bud cell or grasshopper testis through permanent
slides.

Materials Required

 Permanent slides of meiosis

 Compound Microscope

Procedure

1. Place the slide on the stage of the microscope.

2. Look for dividing cells with lower magnification.

Observations
The different stages of meiosis are observed along on the basis of the following features.

Stages of Meiosis I
Prophase I
In this stage, the chromosomes condense and move towards the centre of the cell. It consists
of five different sub-phases:

 Leptotene: The homologous chromosomes replicate.

 Zygotene: Synapsis between homologous chromosomes start.
 Pachytene: The sister chromatids separate but the homologous chromosomes remain
attached.
 Diplotene: The two homologous chromosomes migrate apart and disintegrate between
the chromosomal arms.
 Diakinesis: The condensation of chromosomes stops at this stage and the chiasmata is
clearly visible under an electron microscope. The nucleolus and the nuclear envelop
disappear at this stage and the centrosome moves to the equator.

Metaphase I
The homologous chromosomes that contain two different alleles for each gene, line up on the
metaphase plate to be separated.
Anaphase I
The separated chromosomes are pulled towards the centrioles on either side of the cell.
Telophase I
The chromosomes are completely pulled apart and new nuclear envelope forms.
Stages of Meiosis II
Prophase II
In this stage, the nuclear envelope disintegrates and centrioles develop.
Metaphase II
The chromosomes line up on the metaphase plate and the chromatids are on either side of the
metaphase plate.
Anaphase II
The sister chromatids separate and are known as sister chromosomes.
Telophase II
The cell divides into two and a new nuclear envelope surrounds the chromosomes.
Study Mitosis in Onion Root Tip
Aimt
To prepare a temporary mount of onion root tip to study mitosis.
Theory
All organisms are made of cells. For an organism to grow, mature and maintain tissue, new
cells must be made.  All cells are produced by division of pre-existing cells. Continuity of life
depends on cell division.  There are two main methods of cell division: mitosis and meiosis.

Mitosis is very important to life because it provides new cells for growth and replaces dead
cells. Mitosis is the process in which a eukaryotic cell nucleus splits in two, followed by
division of the parent cell into two daughter cells. Each cell division consists of two events:
cytokinesis and karyokinesis.  Karyokinesis is the process of division of the nucleus and
cytokinesis is the process of division of cytoplasm.

The meristamatic cells located in the root tips provide the most suitable material for the
study of mitosis. The chromosome of monocotyledonous plants is large and more visible,
therefore, onion root tips are used to study mitosis. Based on the kind of cells and species
of organism, the time taken for mitosis may vary. Mitosis is influenced by factors like
temperature and time

Materials required

 Onion , blade, watch glass,  forceps, aceto-alcohol (1:3: glacial acetic acid: ethanol), N/10
HCL, needle,cover slip, Acetocarmine stain.

Procedure:

 Take an onion and place it on the tile.

 Carefully remove the dry roots present using a sharp blade.
 Grow root tips by placing the bulbs in a beaker filled with water.
 New roots may take 3–6 days to grow.
 Cut off 2–3 cm of freshly grown roots and let them drop into a watch glass.
 Using a forceps, transfer them to the vial containing freshly prepared fixative of
aceto-alcohol (1:3: glacial acetic acid: ethanol).
 Keep the root tips in the fixative for 24 hours.
 Using a forceps, take one root and place it on a clean glass slide.
 Using a dropper, place one drop of N/10 HCl on the root tip followed by 2–3 drops
of acetocarmine stain.
 Warm it slightly on burner. Care should be taken that the stain is not dried up.
 Carefully blot the excess stain using filter paper.
 Using a blade, cut the comparatively more stained tip portion of the root, retain it
on the slide and discard the remaining portion.
 After that, put one drop of water on the root tip.
 Mount a cover slip on it using a needle.
  Now, slowly tap the cover slip using the blunt end of a needle so that the
meristematic tissue of the root tip below the cover slip is properly squashed and
spread as a thin layer of cells.
 This preparation of onion root tip cells is now ready for the study of mitosis.
 Place the slide under the compound microscope and observe the different stages of
mitosis.

Various stages of mitosis are prophase, metaphase, anaphase and telophase.

Events during Mitosis

1. Prophase:

0. Mitosis begins at prophase with the thickening and coiling of the

chromosomes.

1. The nuclear membrane and nucleolus shrinks and disappears.

2. The end of prophase is marked by the beginning of the organization of a

group of fibres to form a spindle.

2. Metaphase

0. The chromosome become thick and two chromatids of each chromosome

become clear. 

1. Each chromosome attaches to spindle fibres at its centromere.

2. The chromosomes are arranged at the midline of the cell.

3. Anaphase

0. In anaphase each chromatid pair separates from the centromere and move
towards the opposite ends of the cell by the spindle fibres.

1. The cell membrane begins to pinch at the centre.

4. Telophase

0. Chromatids arrive at opposite poles of cell.

1. The spindle disappears and the daughter chromosome uncoils to form

chromatin fibres.

2. The nuclear membranes and nucleolus re-form and two daughter nuclei
appear at opposite poles.

3. Cytokinesis or the partitioning of the cell may also begin during this stage.

The stage, or phase, after the completion of mitosis is called interphase.  It is the non
dividing phase of the cell cycle between two successive cell divisions.  Mitosis is only one
part of the cell cycle. Most of the life of a cell is spent in interphase.  Interphase consist of
three stages call G1, S and G2.
Study of plant population density by quadrat method

Theory
A population is a group of individuals of the same species which inhabit a particular space
at a particular time. The number of individuals in a population never remains constant. It
may increase or decrease due to many factors like birth rate, death rate and migration. The
number of individuals of the species in any unit area at a given time is its population
density. The unit area may be as small as 5 square centimeters to as large as 10 square
metres, depending on the size and nature of the plant community under study.

Counting all individuals in a population is the most accurate way to determine its size.
However, this approach is not usually feasible, especially for large populations or extensive
habitats. Scientists usually calculate plant populations with the quadrat method. A quadrat
is a square that encloses an area within a habitat.  For herbaceous vegetation, a metre
square quadrat is normally used.

Once analyzed, the sample data enables the scientist to calculate the population size and
population density for the entire population. Population density is calculated by counting
all the individuals present at a given time in a given space, divided by the number of units
of area or space.

Population density is calculated as follows:

Density   = (Total no. of individuals of the species in all the sampling unit (S))/(Total number
of sampling units studied (Q))

Procedure

 In the selected site of study, hammer the nails firmly without damaging the
vegetation.
 Fix four nails to make a square.
 Tie each end of the nails using a thread, to make a 1 m X 1 m quadrat.
 Similarly make five more quadrats randomly in the site of study.     
 Count the number of individuals of a species “A” present in the first quadrat.
 Record the data in the table.
 Similarly count the number of individuals of the species “A” in other quadrats
respectively and record the data in the table.
 Count the number of individuals of a species “B” present in the all quadrat.
 Record the data in the table.
 Repeat the same procedure for species C and record the data in the table.
 Calculate the density of plant population by this equation:
 Density =Total number of individuals of the species in all the sampling unit (S) /
Total number of sampling units studied (Q)

 Precautions:

The measurement of quadrat should be accurate.

      
 The string or cord used should not be very thick.
        

Observations

Plant Number of individuals in each quadrat Total Total Density

Species Number of Number D=(S/Q)
Individuals of
(S) Quadrats
Studied
(Q)

I II III IV V

The density value thus obtained is then expressed as number of individuals per unit area.
Study the plant population frequency by quadrat method.

Aim:

To study population density and percentage frequency of different plant

species of a given area by quadrat method.

Principle:

The number of individuals in a population never remains constant. It may

increase or decrease due to many factors like birth rate, death rate, migration,
etc. The number of individuals of a species presents per unit area or space of a
given time is called population density. The population density and percentage
frequency of different plant species can be determined by laying quadrats /
segments of suitable size and recording of the number of individuals of each
species occurring in the quadrat.

Procedure

 In the selected site of study, hammer the nails firmly without damaging
the vegetation.
 Fix four nails to make a square.
 Tie each end of the nails using a thread, to make a 1 m X 1 m quadrat.
 Similarly make five more quadrats randomly in the site of study.     
 Count the number of individuals of a species “A” present in the first
quadrat.
 Record the data in the table.
 Similarly count the number of individuals of the species “A” in other
quadrats respectively and record the data in the table.
 Count the number of individuals of a species “B” present in the all
quadrat.
 Record the data in the table.
 Repeat the same procedure for species C and record the data in the
table.
 Calculate the density of plant population by this equation:
 Percentage Frequency= (Number of sampling units in which the species
occurs)/ (Total number of sampling units employed for the study) *100
Observation and Inference:

Precautions:

·        The measurement of quadrat should be accurate.

·        The string or cord used should not be very thick.

Isolation of DNA from available plant material

Aim:

To isolate DNA from available plant materials such as spinach leaves, fresh
green pea seeds, green papaya, etc.

Requirements:

Plant materials, mortar and pestle, beakers, test tubes, ethanol, etc.

Procedure:

Take a small amount of plant material and grind it in a mortar with a little
amount of water and sodium chloride.

Make it into a solution and filter it.

To this filterate, add liquid soap solution or any detergent solution and mix it
with a glassrod.

Tilt the test tube and add chilled ethanol and leave it aside in the stand.

After half-an-hour we can observe the precipitated DNA as fine threads.

DNA that separates can be removed by spooling DNA that separates can be

removed by spooling
Observation:

DNA appears as white precipitate of very fine threads on the spool.

Inference:

Thus, DNA can be isolated from the plant cell nucleus by this technique.

Precautions:

·        All the glass wares must be thoroughly cleaned and dried.

·        The chemicals used for the experiments must be of standard quality.

·        If ordinary ethanol is used, the time duration for obtaining precipitated DNA
may extend further.
Prepared pedigree charts of any one of the genetic traits such as rolling of
tongue, blood groups, ear lobes, widow's peak and colour blindness.

Aim To prepare pedigree charts of any one of the genetic traits such as rolling
of tongue, blood groups are lobes, widow’s peak and colour blindness
To prepare and analyse the pedigree charts.

Materials required
Information about traits in a family for more than one generation.

Procedure
1. Select a family with anyone of the monogenic traits like rolling of tongue,
blood groups, ear lobes,
widow’s peak, and colour blindness.
2. Ask the person exhibiting the trait as to who in his/ her family has the trait in
question.
3. Prepare a pedigree chart on the basis of the information collected, using
appropriate symbols.
4. Examine the pedigree chart carefully to find out whether the disease is
autosomal recessive, autosomal dominant, X-linked dominant or recessive, and
Y-linked dominant or recessive.

Explanation
Autosome Linked Dominant Trait- Blood Groups, Free hanging earlobes, Widow’s
Peak, Rolling of tongue
Autosome Linked Dominant traits: These are the traits whose encoding gene is
present on any one of the autosomes, and the wildtype allele is recessive to its
mutant allele, i.e., the mutant allele is dominant.
The pedigree-chart can be of the undernoted pattern, where the female being
interviewed is exhibiting the trait, and is indicated by an arrow-mark in the
chart.

1. The traits get transmitted from the parents to either gender.

2. It affects males and females equally.
3. The trait is present in each of the generations, i.e., the pedigree is vertical.
4. Some common traits of this type include blood groups, polydactyly, brachydactyly, the
dimple in cheeks, etc.

Autosomal Recessive Trait

The mutant allele of such traits is recessive. Salient features of such type of traits include:
1. It is found equally in multiple male and female siblings whose parents are carriers.
2. Affected individuals are homozygous for defective alleles, but their parents, though some
may appear normal, are obviously heterozygous, i.e., are merely carriers of the trait.
3. Consanguinity (marriage between man and woman genetically related to each other, such as
cousins) occasionally results in the appearance of such traits..

(DO NOT WRITE)

Example Suppose the given trait is albinism. Denote its dominant allele as ‘A’ that produces
pigments, and the recessive allele as ‘a’ that fails to synthesise the pigment, melanin The female (our
subject in generation III) is therefore of genotype aa. She must have received each of her ‘a’ allele
from both the parents (generation-II), who are therefore themselves normal but are definitely of
genotype Aa, and are carriers of the trait.
X-Linked Dominant Traits

The encoding gene for such traits is located on the X chromosome. The mutant allele is
dominant in this trait.
The features of such type of traits are:
1. Inheritance is vertical and is found in all the generations.
2. If the female is affected, half of her sons are also affected.
3. If the male is affected, all the daughters will be affected but no sons will be affected, i.e.,
there is no male-to-male transmission.

Example is oral-facial-digital syndrome (Duchene Muscular Dystrophy), which results in absence of

teeth, cleft (bifid) tongue associated with mental retardation
X-Linked Recessive Traits- Colour Blindness

These are the traits whose encoding gene is present on the X-chromosome and its mutant allele is
recessive to its wild-type allele.
Red-green colour blindness and hemophilia, are some of its well-known examples.
The characteristic features of such inheritance are:
(a) Females express the trait only when they are homozygous for the mutant allele, whereas the
males do so even when they are hemizygous for it.
(b) About half of the sons of the carrier (heterozygous for the trait) females are affected. In case of
homozygous females showing the trait, fifty percent of her daughters and all of her sons are likely to
be affected. Therefore, the males are most affected in the population.
(c) Affected persons are related to one another through the maternal side of their family. (d) Any
evidence of male-to-male transmission of the trait rules out the X- linked inheritance.
The pedigree chart would appear as the following on
Y-chromosome linked traits:
Hypertrichosis of the ear (presence of hairs on pinna) is one most common example of such traits
These are the traits whose gene is present on the Y-chromosome. The females do not have
any Y-chromosome, whereas all the males must have a Y-chromosome to be a male, and
this Y-chromosome they get from their father. Therefore, any trait linked to the Y-
chromosome must be present only in males, and certainly not in any of the females. This is
why these traits are also called male-sex limited traits. All the sons of the affected male
would express the trait whereas none of his daughters would do so
Flowers adapted to pollination by different agencies (wind, insects, birds).
As the pollen is not capable of locomotion, pollination involves some agents for transfer of pollen
grains especially in case of cross pollination.

ABIOTIC AGENTS
Anemophily (Pollination by air/ wind)
Adaptation
• Flowers- inconspicuous, usually not brightly coloured or scented • Petals are either small and
green or absent
• Male flowers are more numerous than female
• Anther are versatile so that they swing freely by air currents
• Pollen grains are smooth walled, relatively light, small and dry so they can be easily blown away by
wind
. • In grasses, pollen grains are relatively heavy and hence are not suitable for transport by wind. To
overcome this problem, the male flowers are borne in the upper part of the inflorescence and the
female in the lower part.
• Examples; Most cereals and palms, Member of Salicaceae (Poplar, willow), Betulaceae (Alder,
hazel, birch), Fagaceae (Oak, beech), Ulmaceae (Elm), Urticaceae (Urtica) etc.

Hydrophily (Pollination by water)

Hydrophilous flower are small and inconspicuous like anemophilous
Hypo-hydrophily
• Pollination takes place completely under water.
• Its more common
• Pollination of flower below water level and is found in submerged plants like Najas, Ceratophyllum
and Zostera
• Aerenchyma present in anther
Epi-hydrophily
• Pollination of flower at the surface of water
• Example - Vallisneria
• Whole male flower break and float on the surface.
• Female flower are raised to the surface by a long spiral stalk.

Most important Biotic agents for pollination

• Entomophily: pollination by Insects
• Ornithophily: pollination by birds
• Chiropteriphily: pollination by bats
• Malacophily: pollination by slug and snail
Entomophily (Pollination by insects)
Pollens are sticky with a rough surface so they may easily stick to insect limbs.
• Special relationship between flowers and insects (Coevolved duringevolution)
• Insects visit flowers to secure food in the from of pollen sap and nectar, to deposit their eggs and
for shelter etc
Conspicuous Flowers: Large and brightly colored
In some species scent is more specific then colour.
Nectar glands are situated in different positions of flowers secreting as sugary fluid called nectar.
Lever mechanism in Salvia of Labiatae (Sage Flower)

Ornithophily (Pollination by birds)

• Not many in number. Pollen grains are attached on beaks/ mouth
• Small birds like humming birds and honey thrushes feed on the nectar of flowers like Bignonia
capreolata and pollinate them• Large flowers of Strelitzia (Musaceae) are pollinated by honey bird.
• Silk cotton, Erythrina and few other trees are visited by birds and these birds may play some role
in pollination.

Cheiroteriphily (Pollination by bats)

• Anthocephalus cadamba, Kigelia Africana, Bauhinia megalandra and some other trees are known
to be pollinated by bats.
• Malacophily: Pollination by snails
• Myremecophily: Pollination by ants
DO NOT WRITE
• Salvia has bilabiate corolla with two epipetalous stamens. The stamen and pistil remains hidden
under the upper lip.
• The short epipetalous filament of each stamen is connected to the distractile connective which is
long and lever like, its two unequal arms separating the two anther lobes.
• The upper lobe of the anther is fertile and lower is sterile.
• When bee enter in flower for nectar at the end of the corolla tube. They push against the united
lower anther lobes thereby bringing down the fertile anther lobes which dust the bee’s back with
pollens
. • When this pollen containing bee visited another flower where pistil is matured, the stigmas
protrude out of the upper lips so that bee pollinating them

Trap Mechanism in Aristolochia

• These possess special traps for Dipteran flies.
• Flower of Aristolochia clematitis is protogynous and having odour smell
• When flies enter in the young upright flower, the flies crawl down the corolla tube pushing the
downward pointed hairs but they cannot come out until these hairs wither away.
• When the anthers mature, pollens bursting out and smeared the flies.
• After anthesis flower bending down and the flies come out with pollens.
• They can enter into another flower and pollinate its stigma
Common disease-causing organisms

Aim: Common disease-causing organisms like Ascaris, Entamoeba, Plasmodium

Ring worm through permanent slides or specimens. Comment on symptoms of
diseases that they cause.

Material required
Preserved slides or specimens of disease-causing organisms like Ascaris, Entamoeba,
Plasmodium and Ringworm.

Procedure
Observe the preserved specimens/slides/photographs and note down the features in the
practical record book. Take care to observe all the minute details and draw labelled
diagrams of the pathogens.

A. Entamoeba
Observe the following features of the parasite in the slide or photograph:
Systematic position
Phylum – Protozoa
Class – Rhizopoda
Type – Entamoeba histolytica

(i) It is unicellular.
(ii) Shape of the cell is irregular due to pseudopodia.
(iii) A single nucleus is present eccentrically in the cell.
(iv) In the nucleus a peripheral ring of granule of nucleoprotein and central karyosome are
observed. Rest of the space in the nucleus looks empty
(v) A few food vacuoles may be seen in the cytoplasm. Contractile vacuoles are absent.
(vi) Mature quadrinucleated cysts may be present.
Entamoeba is an intestinal parasite in humans and causes amoebic dysentery.
The symptoms of the disease are frequent loose, mucus filled watery stools, abdominal pain
and spasms.
Plasmodium vivax
Systematic position
Phylum – Protozoa
Class – Sporozoa
Type – Plasmodium vivax

(i) It is an intracellular endoparasite seen easily within the RBC of the infected person.
(ii) It is unicellular.
(iii) The most diagnostic stage of the parasite is "signet ring" stage in the erythrocytes, within which
it appears as a rounded body
(iv) It has a big vacuole inside, and the cytoplasm is accumulated at one place containing the nucleus.
Because of the above mentioned features, the parasite appears as a ring.

It is a protozoan parasite causing malaria in humans. When an infected female anopheles mosquito
bites a healthy person, it injects the infective stage, sporozoite, into the peripheral blood vessels.
The infective stage undergoes several rounds of multiplication in liver and erythrocytes.

Symptoms: Intermittent high fever with chills followed by profuse sweating at an interval of
alternate days.

Ascaris
Systematic position
Phylum – Aschelminthes
Class – Nematoda
Type – Ascaris lumbricoides

The external features of round worm are as follows:

(i) Body long (20 to 40 cm), cylindrical (5 to 6 mm diameter) with no segmentation
(ii) Sexes are separate; the females are longer than the males.
 (iii) Both the ends are pointed; posterior end of male is ventrally curved.
(iv) Mouth is situated at the anterior end, and is surrounded by three lips, one present middorsally
and rest two lips are situated ventrolaterally (for viewing these lips a magnifying lens is needed).
(v) Single longitudinal lines are present on the dorsal, ventral and on the two lateral sides, all along
the length of the body. Out of these the lateral lines are comparatively more distinct than the others
lines.
(vi) Excretory pore is present on the ventral surface slightly behind the anterior end.
(vii) In addition to the ventrally curved posterior tip, the male worm has a pair of penial spicules
very close to the cloacal opening.
(viii) In case of female specimen a female genital aperture is present mid-ventrally about one third
distance from the anterior end.

Round worm or Ascaris is one of the common parasite found in the intestine of human beings.
Symptoms:
Irregular bowel, Occasional vomiting, Anaemia

Trichophyton (Ringworm fungus)

Systematic position
Kingdom – Fungi
Class – Deuteromycetes
Type – Trichophyton rubrum

It is a fungus that feeds on keratin of the skin of human beings. The features as observed under the
microscope are:
1. Texture of hyphae is waxy, glabrous to cotton like
2. Unstained hyphae are white, yellowish brown to reddish brown in colour.

Symptoms
Ringworm is a contagious fungal infection of the skin. Infected area of skin is itchy, red, raised, scaly
patches (with sharply defined edges). It is more red on the periphery than in the center creating a
ring like appearance.
Exercise on controlled pollination

Conventional plant breeding programmes involve bringing under human control

reproductive processes that lead to seed and fruit formation. For this controlled pollination
is desirable using male and female parents using desired traits. One of the processes that
can be easily brought under human control is emasculation. For this the knowledge of
flower structure, mechanism of pollination, fertilisation and physiology of flowering is
essential for this. In emasculation technique the stamens are removed before anthesis to
obtain female parent and pollen from desired male parent is transferred on to the stigma.

Materials required
Ornamental or wild plants bearing large bisexual flowers, magnifying lens, tweezers, scissors , brush,
alcohol, rubber bands, paper bags ,paper clips and tags.

Procedure

(i) Select a flower in bud condition where antheses has not occurred. Open the bud carefully and
remove the stamens. Mark this as female parent plant.

(ii) Cover the emasculated flower with a plastic bag to protect it from undesired pollen (Bagging)).
The bag should be held securely in place with a paper clip/ string/thread. Select the size of bag in
accordance with the flower size. Bags must be transparent with minute pores.

(iii) Bring into physical contact anthers of a desired male plant containing mature pollen grains with
the stigmatic surface of emasculated female flower .Use tweezers/brush if necessary to dust the
stigmatic surface with pollen.

(iv) Cover the pollinated flower again with the bag immediately. For identification, label the female
parent (Tagging). Each pollinated flower should bear a label containing the name of the seed parent,
the letter X (to signify a cross), the name of the pollen parent, and the date on which the cross was
effected.
 Mendelian Inheritance Using Seeds Of Different Colours/ Sizes Of Any Plant

Aim
To study the Mendelian inheritance using seeds of different colours/sizes of any plant.

Necessary Materials & Apparatus

 Petri Dish
 Enamel Tray
 Pea Seed Samples

Procedure

 Place 100 pea seeds in an enamel tray

 Separate the seeds into round and wrinkled and place them in two separate Petri
dishes
 Note down the number of round and wrinkled seeds. Also, calculate their ratio.
 Repeat the procedure mentioned above for other contrasting traits such as the colour
of the seeds.

Observation

 Create a table showing the characteristics of the seed along with the total number
observed, number of seeds with contrasting characters and the ratio.

Serial Number Characteristics Total number Seeds showing Ratio

of seeds contrasting
characters
Shape of the round seeds;
seed wrinkled seeds
Colour of the Green seeds:
seed yellow seeds
Procedure
Students are to work in pair. The following steps are to be followed sequentially:
(i) Place 64 beads of each colour in four separate beakers.
(ii) Put the beakers containing the yellow and red beads on your left side, and those containing the
green and white beads on your right side. The beakers on your left side represent plants bearing
yellow seed and red flower (dominant character YY, RR). Beakers on the right side represent plants
bearing green seeds and white flowers (recessive character yy, rr). These are the two parental types
having contrasting forms of two different characters. (iii) Stir the beads in each beaker with a
pencil/pen. Each bead now represents alleles in the male and female gametes. (iv) Pick up one
yellow, one green, one red and one white bead, and put them together on the napkin spread on the
table. (v) Continue picking up and putting together of the beads of all colours as mentioned in the
previous step, till all the beads are utilised. (vi) Note that in all, 64 such 4-bead clusters are obtained
representing the F1 individuals. Ascertain their genotype and phenotype. (vii) Next step is to cross
these F1 individuals to raise the F2 generation. Let us suppose half of the 4-bead clusters (32
clusters) represent the male parents and the remaining half (32 clusters) the female parents. Now
put the 32 red and 32 white beads together in one beaker (numberedI), and similarly put 32 yellow
and 32 green beads together in other
beaker (numbered-II). These two beakers represent F1 female. Similarly put remaining 32 red + 32
white beads in beaker numbered-III, and 32 yellow and 32 green one in beaker numbered-IV to
represent the F1 male. The arrangement can be presented as below