BALUNI PUBLIC SCHOOL
AGRA
BIOLOGY INVESTIGATORY FILE
Session:2024-25
Submitted by: Submitted to:
VAIDANSH CHAURASIA
Class 12th science
Roll no. –
INDEX
➢ Certificate
➢ Acknowledgment
➢ Theory
➢ Requirements
➢ Procedure
➢ Observations
➢ Identifying points
➢ Precautions
CERTIFICATE
This is to certify that VAIDANSH CHAURASIA student
of class 12th science has successfully completed the
report on the project given “ Pollen germination in
stigma through a permanent slide ” under the
guidance of
It is further certifying that this project is the individual
and bona-fide work of the candidate.
Signature of Signature of
Biology teacher External invigilator
ACKNOWLEDGMENT
I would like to express my sincere gratitude to my
biology teacher Mr. for the
vital support, guidance and encouragement without
which this project would not have come forth by my
side.
I wish to extend my heartiest thanks to my parents and
my friends for their individual support and interest
which inspired me and encouraged me to go ahead.
THEORY
Another event during the life cycle of gymnosperms
and flowering plants is the germination of a pollen
grain after pollination. Pollen grain are haploid, first
cell of male gametophyte which are produced in
anthers by meiosis.
Once the pollen grain lands on the stigma of a
receptive flower, it takes up water and germinates.
Pollen can also be induced to germinate in vitro.
During germination ,the tube cell elongates into a
pollen tune. In the flower ,the pollen tube then grows
towards the ovule where it discharges the germ cells
produced in the pollen grain for fertilization. The
germinated pollen grain with its two germ cells is the
mature male micro gametophyte of these plants.
The pollen grains can be germinated in laboratory by
‘hanging drop’ method in sucrose solution with a
pinch of boric acid and Ca , Mg and K salts.
REQUIREMENTS
• Mature flower
• Needles
• Slide and cover slip
• Dissecting microscope
• Compound microscope
• Safranine and glycerin
PROCEDURE
1. Take a fresh mature flower.
2. Separate the pistil or stigma from the flower by
removing their sepal, petals and stamens.
3. Pistil is opened and mature.
4. Now stain the pistil stigma with safranine stain on
the slide.
5. Now mount the stained stigma with glycerin and
cover it with cover slip.
6. Observe under dissecting microscope.
7. Now take a germinating pollen from the slide and
mount it with glycerin on another slide and cover
it with cover slip.
8. Now observe it under compound microscope.
OBSERVATION
1) On the stigma, number of pollen grains are
present.
2)These pollen grains germinate on the stigma.
3)Pollen absorb water and take food for its growth
from the stigma.
4)Pollen germinates and forms the pollen tube. In
the stigma, substance like sugar or organic acid is
taken which further stops the growth of pollen
tube.
5)Pollen tube enlarge in size, passes from the
stigma to style and then enter into ovule of ovary.
6)Pollen has two male gametes which get fertilized
with female gametes present in the ovule.
IDENTIFYING POINTS
▪ Pollen grain are found on the stigma of flowers
▪ Pollen germinates and swell up due to
absorption of water and other substances from
stigma.
▪ Pollen has two layers, intine and exine. Intine
protrudes outside and forms the pollen tube.
▪ Pollen tube has a nucleus and two male
gametes.
▪ This tube now enter into the ovule.
PRECAUTIONS
1. Flower must be fresh and mature.
2. Pistil or stigma is separated carefully
without damaging the ovary.
3. Air bubble should not be present during
mounting of slides.
4. Do not over stain the slide.
