This document summarizes the process of fertilization in plants. It describes the stages of fertilization from the pollen landing on the stigma through the entry of the pollen tube into the embryo sac. It then explains that angiosperms undergo double fertilization, where one male gamete fuses with the egg cell to form a zygote, and the second male gamete fuses with the two polar nuclei to form the endosperm. This double fertilization process, involving the fusion of three nuclei, is significant as it allows for embryo and endosperm formation, leading to viable seed production.
Fertilization is the process of fusion of the female gamete, the ovum or egg and the male gamete produced in the pollen tube by the pollen grain. Fertilization in flowering plants was discovered by Strassburger in 1884.
Flowers are the reproductive structures of angiosperms. They vary greatly physically and are of great diversity in methods of reproduction. The process of fertilization in plants occurs when gametes in haploid conditions meet to create a zygote which is diploid.
The male gametes of the flower are transferred on to the female reproductive organs through pollinators. The final product of this process is the formation of embryo in a seed.
In this lesson you will learn about :
1) What is Fertilization?
2) The Pollen Grain (Male Gamete)
3) The Ovule (Containing Female Gamete)
4) Microsporogenesis and Megasporogenesis
5) Germination of Pollen Grain
6) Double Fertilization
7) Post Fertilization Events
I hope this document is helpful to you. Please share the document with your friends if you think this will benefit them. Get ready for the next lesson. Thanks.
Pollen pistil interaction
Types of Incompatibility in plants
Methods to overcome Incompatibility
Prepared by
Dr. T. Annie Sheron
Assistant Professor of Botany
DEPARTMENT OF BOTANY
KAKATIYA GOVERNMENT COLLEGE, HANAMKONDA
Wall layers of anther have different functions most importantly they help in providing nutrition to developing pollens and also help in anther dehiscence.
Plant fertilization is the union of male and female gametes (reproductive cells) to produce a zygote (fertilized egg)
Double Fertilization
Both the male gametes/sperms participate in sexual reproduction.
Two male gametes fuse with one female gamete wherein one male gamete fertilizes the egg to form a zygote, whereas the other fuses with two polar nuclei to form an endosperm
Triple fusion is the fusion of the male gamete with two polar nuclei inside the embryo sac of the angiosperm.
Porogamy - entry through the micropyle.
Chalazogamy - entry through the Chalaza
Mesogamy - entry through the middle part or the integuments
Steps leading to fertilization
Germination of the pollen grain:
Stigma function is to provide place of lodging and germination of the pollen grain after pollination.
Types of stigmas-
Wet stigmas
Secrete exudates like water and other nutrients
In the form of droplets on the stigma.
Exudates made up of a mix of water, lipids, sugars, amino acids, phenolic compounds.
Highly viscous and adhesive. Ex: Petunia, Zea etc.
Dry stigma
Do not secrete exudates Ex: Gossypium
Double Fertilization & Triple Fusion:
Both the male gametes are involved in the fertilization.
Fertilize two different components of the embryo sac - Double Fertilization
One fuses with the egg nucleus (syngamy) -> Zygote(2n)
second fuses with polar nuclei -> primary endosperm nucleus (PEN).
Involves fusion of three nuclei - Triple fusion -> Endosperm(3n)
Pollen tube in the synergids:
Entry only through micropyle. Guided by oburator
Presence of chemotropic substances
Collapse of one the synergids prior to entry of the pollen tube.
Pollen tube in the synergids:
Entry only through micropyle. Guided by oburator
Presence of chemotropic substances
Collapse of one the synergids prior to entry of the pollen tube.
Discharge of pollen tube contents (two male gametes, vegetative nucleus and cytoplasm) into the synergids.
Disorganization of tube nucleus
Polyspermy &Heterofertilization
Heterofertilization - Type of double fertilization in plants in which endosperm and embryo are genetically different.
This happens when two different sperm nuclei from two different pollen tubes happen to enter the same embryo sac.
Dr. T. Annie Sheron
Annie Sheron
Kakatiya Government College
Fertilization is the process of fusion of the female gamete, the ovum or egg and the male gamete produced in the pollen tube by the pollen grain. Fertilization in flowering plants was discovered by Strassburger in 1884.
Flowers are the reproductive structures of angiosperms. They vary greatly physically and are of great diversity in methods of reproduction. The process of fertilization in plants occurs when gametes in haploid conditions meet to create a zygote which is diploid.
The male gametes of the flower are transferred on to the female reproductive organs through pollinators. The final product of this process is the formation of embryo in a seed.
In this lesson you will learn about :
1) What is Fertilization?
2) The Pollen Grain (Male Gamete)
3) The Ovule (Containing Female Gamete)
4) Microsporogenesis and Megasporogenesis
5) Germination of Pollen Grain
6) Double Fertilization
7) Post Fertilization Events
I hope this document is helpful to you. Please share the document with your friends if you think this will benefit them. Get ready for the next lesson. Thanks.
Pollen pistil interaction
Types of Incompatibility in plants
Methods to overcome Incompatibility
Prepared by
Dr. T. Annie Sheron
Assistant Professor of Botany
DEPARTMENT OF BOTANY
KAKATIYA GOVERNMENT COLLEGE, HANAMKONDA
Wall layers of anther have different functions most importantly they help in providing nutrition to developing pollens and also help in anther dehiscence.
Plant fertilization is the union of male and female gametes (reproductive cells) to produce a zygote (fertilized egg)
Double Fertilization
Both the male gametes/sperms participate in sexual reproduction.
Two male gametes fuse with one female gamete wherein one male gamete fertilizes the egg to form a zygote, whereas the other fuses with two polar nuclei to form an endosperm
Triple fusion is the fusion of the male gamete with two polar nuclei inside the embryo sac of the angiosperm.
Porogamy - entry through the micropyle.
Chalazogamy - entry through the Chalaza
Mesogamy - entry through the middle part or the integuments
Steps leading to fertilization
Germination of the pollen grain:
Stigma function is to provide place of lodging and germination of the pollen grain after pollination.
Types of stigmas-
Wet stigmas
Secrete exudates like water and other nutrients
In the form of droplets on the stigma.
Exudates made up of a mix of water, lipids, sugars, amino acids, phenolic compounds.
Highly viscous and adhesive. Ex: Petunia, Zea etc.
Dry stigma
Do not secrete exudates Ex: Gossypium
Double Fertilization & Triple Fusion:
Both the male gametes are involved in the fertilization.
Fertilize two different components of the embryo sac - Double Fertilization
One fuses with the egg nucleus (syngamy) -> Zygote(2n)
second fuses with polar nuclei -> primary endosperm nucleus (PEN).
Involves fusion of three nuclei - Triple fusion -> Endosperm(3n)
Pollen tube in the synergids:
Entry only through micropyle. Guided by oburator
Presence of chemotropic substances
Collapse of one the synergids prior to entry of the pollen tube.
Pollen tube in the synergids:
Entry only through micropyle. Guided by oburator
Presence of chemotropic substances
Collapse of one the synergids prior to entry of the pollen tube.
Discharge of pollen tube contents (two male gametes, vegetative nucleus and cytoplasm) into the synergids.
Disorganization of tube nucleus
Polyspermy &Heterofertilization
Heterofertilization - Type of double fertilization in plants in which endosperm and embryo are genetically different.
This happens when two different sperm nuclei from two different pollen tubes happen to enter the same embryo sac.
Dr. T. Annie Sheron
Annie Sheron
Kakatiya Government College
Presentation on the relevance of self-incompatibility, methods to overcome self-incompatibility, advantages and disadvantages, utilization in crop improvement
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Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
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IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
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A brief information about the SCOP protein database used in bioinformatics.
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1. Presented By
Dr. V. RAMSEH,
Assistant Professor & Head i/c
Department of Botany
Vivekananda College
Tiruvedakam West – 625 234
ramesh.vnr09@gmail.com
+91 9842629245
FERTILIZATION IN PLANTS
2. What is Fertilization?
Fusion of male and female gamete is called
fertilization. Fertilization in angiosperms is
double fertilization type.
3. Stages of fertilization
Pollen on the stigma
Pollens fall on the receptive stigma
Receives stigmatic fluid in wet stigma and pellicle in dry stigma
Recognition-rejection protein reaction
Pollen wall proteins are released
Pollen tube germination
• Pollen tube in the style
Pollen tube enters into the style
4. Entry of pollen tube into the ovule
pollen tube entry into the ovule
Porogamy: pollen tube enters through the micropyle.
Chalazogamy: pollen tube enters through the chalaza.
Mesogamy: pollen tube enters through the integument.
5. Entry of pollen tube into embryo sac
Pollen tube enter through obturator
After reaching the embryo the content of the pollen tube (two male
gametes, vegetative nucleus and cytoplasm) are discharged into the
synergids
6. DOUBLE FERTILIZATION AND TRIPLE FUSION
Fertilization in Angiosperm
Double Fertilization
S.G. Nawaschin and L.Guignard in 1898
and 1899, observed in Lilium and
Fritillaria that both the male gametes
released from a male gametophyte are
involved in the fertilization.
One male gametes fuses with the egg
nucleus (syngamy) to form Zygote. Second
gamete fuses polar nuclei forms the
primary endosperm nucleus (2N).
This involves the fusion of three nuclei
triple fusion.
7. SIGNIFICANCE
Embryo formation takes place
Endosperm formation
Production of viable seeds also the significance of double fertilization
POST FERTILIZATION CHANGES
