This PPT mainly deals with basic understanding of the anther & pollen biology with special reference to the anther wall structure and function for UG college students as study content.

1. Welcome to
Anther & Pollen Biology: Anther wall-structure &
Function
By N.Sannigrahi, Associate Professor, Department of
Botany, Nistarini College, Purulia, 723101(W.B) India
In flower, the microsporophyll or stamen
considered as male reproductive organ consists
of filament , connective & anther
Anther- monothecous(two locules) or dithecous
(four locules or sporangia)
Development is eusporangiate(Sporangium
developing from a group of cells) having
archsporium and epidermis in t.s

2. Flower splits open

3. Inside the anther

4. Composition

5. Anther wall
• The archesporial cells divide periclinally
giving rise to primary parietal cells on the
outer side and sporogenous cells towards inner
side.
• The cells of the parietal layers divide
periclinally and anticlinally forms
endothecium, middle layers & tapetum,
• The cells of the primary sporogenous tissue
differentiated into pollen mother cells or
microspore mother cells

6. Continuation------
• The anther wall consists of the following walls layers:
• Epidermis-the outermost layers, compact and
protective
• Endothecium-elongated with U shaped fibrous bands
made up of callose, hygroscopic, helps in dehiscence
at maturity, single layered
• Middle layers-2-3 layers, ephemeral and become
crushed by early meiosis in PMC, storage centers of
starch
• Tapetum-Innermost layers of anther walls, surrounds
the sporogenous tissue

7. Types of anther wall
• Based on the behavior of the secondary
parietal layers, Davis(1966) recognized
• Basic type
• Dicotyledonous type
• Monocotylednous type
• Reduced type

8. Basic type

9. Basic type-most primitive
• Primary parietal wall undergoes periclinal
division forming outer and inner secondary
parietal layers----Both layers undergoes
periclinal division----One towards epidermis
differentiates into endothecium followed by
middle layers-----Another secondary parietal
layers produces middle layer and tapetum---
• e.g Members of Anacardiaceae, Rhamnaceae,
Tiliaceae

10. Reduced Type

11. Reduced type
• Here, Primary parietal layers undergoes periclinal
division forming 2 secondary layers------Outer
layer functions as Endothecium----Inner layers
functions as Tapetum----Middle layers absent
• E.g. Members of Lemnaceae
• The basic difference in between two types is that ,
Basic type contains middle layers and in Reduced
middle layers are absent. These wall layers like
endothecium is protective, middle layers for food
reserves and Tapetum for nutrition.

12. Tapetum
• Tapetum is the innermost layer of anther walls
and completely surrounds the sporopgenous
tissue
• The cell contain dense cytoplasm with
prominent nuclei,
• Tapetum consists of single layers of cells
• It transports the nutrients to the developing
sporocytes .It is pigmented and red brown in
Apple or violet in Anemone.

13. Type of Tapetum
• Depending upon the behavior , tapetum is of 2
type
• 1. Amoeboid tapetum-Primitive type, during
the drying up process of anther,
periplasmodium hydrates and deposits as
tryphine on the wall of pollen grain
• 2. Secretory tapetum-It remains attached to the
middle layers till the development of pollen
grains. It is more common among angiosperm.

14. Tapetum
• It provides nourishment to the developing pollen
grain.
• It helps in the formation of exine.
• Helps to the transport of food material to inside of the
anther.
• Tapetum helps in the formation of pollen grains.
• Pollen kit (Lipid & Carotenoids) is formed by tapetal
layer acts as insect attractant & protect pollen from
UV.
• It involved in the synthesis of callose which releases
microspores in a tetrad by degrading callose wall.

15. Functions of anther cell & tissues type
• Connective-Join anther theca together, connect
anther to filament, structure, support &
morphology
• Circular cell cluster-Dehiscence
• Endothecium-Structure & support, dehiscence
• Epidermis-Structure & support, prevent water
loss, Gas exchange, dehiscence
• Middle layer-Structure & support, Dehiscence
• Stomium-Dehiscence
• Tapetum-Nutrition of pollen development
• Vascular bundle-Nutrient & water supply

16. Gene markers for Tobacco anther cell types(Scott et al
1991)
mRNA Protein encoded Cell specifity
TA13 Glycine rich Tapetum
TA20 Unknown Connective, stomium
TA26 Unknown Tapetum
TA29 Glycine rich Taspetum
TA32 Lipid transfer Tapetum
TA36 Lipid transfer Tapetum
TA39 Unknown Tapetum, microspore
TA55 Unknown Tepetum, connective,
middle layer
TA56 Thiol endopeptidase Connective, circular cell
cluster, Stomium

17. Let us make a strong wall against COVID19 by
Physical distancing. Thank you