Keshav Narayan PaiMsc I

DOS in BotanyManasagangotri

Anther wall development – Reduced and Basic type

Content Introduction Anther wall development Basic Type Reduced Type Conclusion References

Introduction

Pollen grains, which contribute the male gametes, are formed within an anther.A typical anther is tetrasporangiate.

Anther Wall Development

A Very young anther comprises a homogeneous mass of cells bounded by a well defined epidermis.

During its development the anther assumes a four lobed appearance.

In each lobe some hypodermal cells become more prominent – these cells constitute the archesporium.

Anther Wall Development

The archesporial cells divide into periclinal division .

Primary parietal cells towards the epidermis.

Primary sporogenenous cells toward the interior of the anther.

The cells of the parietal layer undergo a series of periclinal & anticlinal divisions – 2 to 5 concentric layers of anther wall.

The primary sporogenous cells, either directly or after a few mitoses, function as microspore mother cell.

Types Based on the behaviour of

secondary parietal layers, Davis (1966) recognised into 4 types of anther wall.

Basic Type Dicotyledonous Type Monocotyledonous Type Reduced Type

Basic Type Primary Parietal layer

Outer Secondary Inner Secondary

parietal layer parietal layer

Endothecium Middle layer Middle layer Tapetum

Basic Type Primary parietal wall undergoes

periclinal division forming outer and inner secondary parietal layers.

Both the layers undergoes periclinal division.

One towards the epidermis differentiates into endothecium followed by middle layer.

Another secondary parietal layer produces another middle layer and the tapetum.

It is the most primitive type. Ex: Anacardiaceae, Rhamnaceae, Tiliaceae.

Reduced Type

Primary Parietal layer

Outer Secondary Inner Secondary

parietal layer parietal layer

Endothecium

Tapetum

Reduced Type Primary parietal layer undergoes

periclinal division forming 2 secondary layers.

Outer layer functions as Endothecium.

Inner layer functions as Tapetum. Middle layers are absent. Ex: Lemnaceae.

Conclusion Only diference between the Basic and Reduced type is that , Basic Type contains middle layers and in Reduced type middle layers are absent.

These wall layers like endothecium is protective, Middle layers are food reservoirs and Tapetum in nutrition.

Bhojwani, S.S. & Bhatnagar, S.P. 1978. The embryology of Angiosperms. Vikas publiser house, New Delhi. Pp:16-28.

Pullaiah.T , Lakshminarayana.K. & Hanumantha rao.B. Plant reproduction. Scientific publishers( India) Jodhpur. Pp: 08-20.

Johri, B.M. 1984. The embryology of Angiosperms. Springer Verlag. Pp:53-67.

References

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