The document explains syngamy, a key process in angiosperm fertilization where a diploid zygote is formed by the fusion of sperm and egg cells. It describes two types of syngamy: self-fertilization and cross-fertilization, along with three forms—isogamy, heterogamy, and oogamy. Additionally, it differentiates syngamy from triple fusion, where syngamy leads to a diploid zygote and triple fusion results in triploid endosperm.

1. SYNGAMY IN PLANT
-Ganesh Sidar
College of Horticulture and Research Station,
Jagdalpur,{CG}

2. INDEX
• What is Syngamy?
• Types of syngamy
• Difference between Syngamy and Triple Fusion

3. What is Syngamy?
An important characteristic of angiosperms is double fertilization,
where two nuclei (of sperm) from each of the pollen tubes go on to
fertilise two other cells that belong to the ovary.
A diploid zygote is formed when one of the sperm cells fertilizes
one of the egg cells. An embryo now develops from this diploid
zygote.
The fusion of the cells in such a scenario is called syngamy. It can
be noted that syngamy is also referred to as true fusion and
generative fertilisation.

4. Types of syngamy
Syngamy is of two kinds on the basis of the source of fusion gametes, which
are
• Self-fertilization or Endogamy: The includes the fusion of two forms of
gametes originating from the same parent for example, Taenia. It is a
process is very uncommon.
• Cross-fertilization or Exogamy: When two fusing gametes for example
in human, frog, cockroach, etc. are derived from separate parents. It is
more general.

5. There are three types of syngamy and they are:
• Isogamy: This occurs when the gametes that fuse are similar. An advanced
system of recognition is used so as to avoid self-fertilization. Surface proteins
such as cells of immune system help in recognizing the different types of
genotypes.
• Heterogamy: This happens when the gametes are of two different sizes. Based
on the division of labor, the difference between the two gametes are done.
Usually the female is larger while the male is smaller. Also, the number of male
gametes is more so that there is an increase in the competition and makes
fertilization likely.
• Oogamy: This takes place when the mobility of the gametes are different.
Oocyte is the non-motile female and spermatozoon is the flagellate male. In
most of the cases, spermatozoon is the only mobile gamete. Spermatozoa and
spermatia are known as sperms.

7. Syngamy Triple fusion
Definition
The fusion of male and female gametes during the
fertilization is known as syngamy
The fusion of the sperm cell with the two polar nuclei
during the double fertilization is known as triple fusion
Development
During syngamy, zygote is produced which forms the
embryo
During triple fusion, endosperm cells are produced
which develops into endosperm
Result
Diploid is the end result of syngamy Triploid is the end result of triple fusion
Difference between Syngamy and Triple Fusion