The document summarizes the structure and development of the anther wall and male gametophyte in angiosperms. It states that the anther wall is made up of epidermis, endothecium, middle layers, and tapetum. The epidermis is the outer layer, endothecium contains fibers that aid in dehiscence, middle layers store food, and the tapetum provides nutrients during development and contributes to pollen wall formation. Microsporocytes undergo meiosis to form microspores within the microsporangia located in each anther lobe.

1. DR. DILIP V. HANDE
PROFESSOR
DEPT OF BOTANY
SHRI SHIVAJI SCIENCE COLLEGE AMRAVATI
SEM- III

3. At maturity, the 2 sporangia of
each side become confluent
due to breaking down of the
partition between them
Endothecium lying immediately
beneath
epidermis, hygroscopic-
aids in dehiscence
Microsporocytes-or
microspore mother cells are
derived from archesporial
cells

4. The anther wall :
In the mature anther the anther wall is
made up of following layers- Epidermis,
Endothecium, Middle layers, Tapetum
.

5. exine
intine
cytoplasm
Pollen from different species, variation
in exine morphology

6. Microsporangium, Microsporogenesis
and Male Gametophyte :
• In the flower of angiosperm the stamen is the
male reproductive organ.
• Each stamen consists of filament, anther and
connective.
• Anthers are present at the tip of the filament.
• The sterile middle part of the anther is called as
connective.
• Each anther contains two lobes and each lobe
again divided in to two sacs or microsporangia.
• Thus the single anther is made up of four pollen
sacs or microsporangia hence described as
tetrasporangiate.

7. Anther still meristematic lobe .Periclinal division occurs beneath the
protoderm, layer called archesporial layer

9. Cells lining the
anther lumen – a
layer known as
the endothecium
– secretes
materials that are
essential for the
proper
maturation of the
pollen grains.

11. •Epidermis:
The outermost layer of anther wall is
called as epidermis. It is single layered.
Epidermis is made up of tangentially
stretched and flattened cells. It performs the
role of protection.

12. Endothecium :
Just below the epidermis layer of endothecium is
present.
Generally it is single layered but in some plants it may
be multilayered.
The cells of endothecium are radially elongated. The
endothecial cells contain fibrous bands which are U-
shaped.
The endothecium helps for dehiscence of the anther
and discharge of pollen.
At the time of dehiscence fibrous bands becomes
hygroscopic and due to which dehiscence of anther
takes place.
These fibrous bands are absent in some cleistogamous
flowers.

13. Middle layers :
The parenchymatous cells which are present
between endothecium and tapetum form middle
layers.
Middle layers are composed of one to three
layers.
The cells of middle layers are ephemeral and
degenerate completely before pollen mother cell
undergoes meiosis.
The middle layers store the food material
which is utilized by pollen mother cells.

14. Tapetum :
Tapetum is the innermost layer of anther
wall.
It is single layer around the sporogenous tissue.
This is layer is physiologically important because
the food material to the sporogenous tissue passes
through it.
Functions of tapetum :
Tapetum play important role in the
development of pollen. The following are some of
the functions of the tapetum-
•During meiosis nutrient are transported to the
inside of anther locule through the tapetum.

15. •Tapetum is involved in the synthesis of callase
enzyme for the release of microspores in tetrad by
degrading the callose wall.
•Tapetum is associated with the development of
pollen grains because when tapetum is
degenerate before microsporogenesis, the pollen
grains produced are sterile or abortive.
•Tapetum play important role in formation of the
exine.
•Pollenkitt substances and tryphine present on
pollen grains are contributed by the tapetum.
•Pollen wall contains proteins derived from the
gametophyte as well as the tapetal cells. These
proteins are responsible for pollen allergy.

17. Sporogenous tissue :
•The pollen grains (microspores) develop
from the sporogenous tissue.
•The primary sporogenous cells directly act
as microspore mother cell (MMC) or divide
to increase their numbers and then act as
MMC.
•Each microspore mother cell undergoes
Meiosis and forms four haploid
microspores.
•The process of formation of microspores is
called as micosporogenesis.