Difference Between Androecium and Gynoecium

Key Difference – Androecium vs Gynoecium
 

In the context of angiosperms, the flower is considered as the reproductive organ. The whole unit is composed of the male reproductive unit (androecium) and female reproductive unit (gynoecium).The androecium is composed of anther and filament while the gynoecium is composed of style, stigma and ovary. Both structures are essential for the reproduction process. The androecium involves in the production and release of pollen grains while the gynoecium is designed to receive mature pollen grains and to facilitate germination by providing a site for fertilization. This is the key difference between Androecium and Gynoecium.

CONTENTS

1. Overview and Key Difference
2. What is Androecium
3. What is Gynoecium
4. Similarities Between Androecium and Gynoecium
5. Side by Side Comparison – Androecium vs Gynoecium in Tabular Form
6. Summary

What is Androecium?

The androecium is considered as the male reproductive unit of the flower. It is an individual component of the flower. It is also referred to as the stamen that is composed of anther and filament. In a typical flower, the anther is held by the filament. The filament is a long structure. It is often referred to as the stalk. The number of anther and filament varies according to the plant species. The androecium is located centrally to the flower. Normally there are about 5-6 stamens located per flower.

The main function of the androecium is to produce pollen grains. They are released from the anther into the external environment only after they mature. Once released, they are received by the stigma of the gynoecium, which is the female reproductive unit of the flower.  The role of the filament is highlighted during pollination. It facilitates self pollination by bending towards the stigma of the same flower. During the time of cross-pollination, the filament bents away from the stigma to prevent self pollination.

The anther is composed of two distinct lobes when observed in a cross-section. Each lobe is composed of two microsporangia. These microsporangia are referred to as thecae. Altogether there are 04 thecae in an angiosperm anther. Analysis of each microsporangium presents 4 cell layers that are present from outside to inside. They are epidermis, endothecium, middle layers and tapetum. The outermost three layers involve the release of pollen grains. The function of the tapetum is to provide adequate nourishment to the developing pollen grains. Pollen grains develop through mitosis. Different pollinating agents decide the fate of the released pollen grains during cross-pollination.

What is Gynoecium?

The gynoecium is the female reproductive unit of the flower. It is also referred to as the pistil.  The gynoecium is composed of three major segments. They are, stigma, style and ovary. The stigma is usually present at the distal end of the style. It is composed of a special type of structures known as stigmatic papillae. These cellular structures are considered as the major receptive component of the stigma that receives and keeps mature pollen grains within the stigma.

The stigma contains a sticky hydrated nature. Once pollen grains are released from the anther, due to the environmental condition, they get dehydrated or desiccated. Rehydration of the pollen grains is taken place in the stigma due to its sticky nature. Providing nourishment to the mature pollen grains is one of the major functions of the stigma. Once the stigma provides the adequate conditions for germination, it facilitates the development of the pollen tube. The pollen tube grows from the stigma towards the ovary along with style. Pollen specificity is recognized by the stigma. If pollen grains of a different species are received, they get rejected by the stigma through the initiation of pollen rejection mechanisms.

The ovary of the plant is considered as an enlarged portion located at the base of the pistil. It contains ovules. The positioning of the ovary in flower (gynoecium) takes place according to three types. They are superior ovary (attached to the receptacle above other floral attachments), half-inferior ovary (partially embedded by the receptacle) and inferior ovary (completely embedded by the receptacle and all the other floral attachments are present above the ovary). Fusion of male gamete (from the pollen) and female gamete (ovules) takes place within the ovary. The development of the zygote into new plants begins from the ovary.

What are the Similarities Between Androecium and Gynoecium?

• Both Androecium and Gynoecium are reproductive units of the flower.
• Both Androecium and Gynoecium produce gametes.

What is the Difference Between Androecium and Gynoecium?

Summary – Androecium vs Gynoecium 

The androecium is considered as the male reproductive unit of the flower. It is also referred to as the stamen that is composed of anther and filament. The main function of the androecium is to produce pollen grains. The gynoecium is the female reproductive unit of the flower. It is also referred to as the pistil.  The gynoecium is composed of three major segments. They are a stigma, style and ovary. The positioning of the ovary in flower (gynoecium) takes place according to three types. Fusion of male gamete (from the pollen) and female gamete (ovule) takes place within the ovary which develops a zygote. This is the difference between androecium and gynoecium.

Reference:

1.Swafford, Angela Lynn . “Androecium: Definition & Concept.”Study.com, Study.com. Available here 
2.Swafford, Angela Lynn . “Gynoecium: Definition & Concept.”Study.com, Study.com. Available here 

Image Courtesy:

1.’Lecythis marcgraaviana androecium, open hood and stamens’By Alex Popovkin, Bahia, (CC BY 2.0) via Commons Wikimedia  
2.’Magnolia wieseneri – labelled gynoecium’By Magnolia_Watsoni.JPG (CC BY-SA 4.0) via Commons Wikimedia