What is the Difference Between Male and Female Gametophyte

The main difference between male and female gametophyte is that the microspore or pollen grain produces the male gametophyte while the megaspore produces the female gametophyte.

Male and female gametophytes are the two gametophytic stages of heterosporous plants. Male gametophyte produces male gametes while female gametophyte produces female gametes. 

Key Areas Covered 

1. What is Male Gametophyte
     – Definition, Structure, Role
2. What is Female Gametophyte
     – Definition, Structure, Role
3. What are the Similarities Between Male and Female Gametophyte
     – Outline of Common Features
4. What is the Difference Between Male and Female Gametophyte
     – Comparison of Key Differences

Key Terms 

Female Gametophyte, Male Gametophyte, Megaspore, Microspore, Ovule, Pollen Grain

What is Male Gametophyte 

Male gametophyte is the male gamete-producing structure. It comes from the microspore produced by the microsporangium in heterosporous plants including angiosperms, gymnosperms, lycophytes, and horsetails. In angiosperms, microsporangium occurs inside the anther while in gymnosperms, it occurs in the pollen cone. In other heterosporous plants, microspores are produced in the microphylls.  

Figure 1: Microsporangia of Pinus

In angiosperms, microspore contains a single haploid nucleus, which undergoes mitosis to produce two nuclei: tube nucleus and generative cell nucleus. Microspore with the two nuclei stage is called the male gametophyte. The male gametophyte contains two tough walls called exine and intine. The whole structure is called the young pollen grain. The male gametophyte inside the pollen grain represents the first stage of growth. It leaves the microsporangium and is captured by the stigma. 

The pollen grain germinates on the stigma, producing the pollen tube, which burrows into the ovary through the style. Moreover, upon germination, the generative cell nucleus produces two germ nuclei, which serve as the male gametes. The germination phase represents the second phase of growth in the male gametophyte, consisting of three cells. 

What is Female Gametophyte 

Female gametophyte is the female gamete-producing structure, which comes from the megaspore. Megasporangium produces the megaspores inside the ovary in angiosperms. In gymnosperms, it is produced in the female cone while in other heterosporous plants, it is produced in megaphylls. A cell inside the nucellus of the ovule known as megasporocyte undergoes meiosis to produce four cells. One of the four cells become the megaspore, which undergoes three mitotic divisions to produce eight haploid nuclei. This stage of megaspore is known as the female gametophyte. One of the haploid cells becomes the egg cell. 

Figure 2: Female Gametophyte

Angiosperms undergo triple fusion; here, one of the germ nuclei from the male gametophyte fuses with the egg nuclei, forming the zygote, and the other germ nucleus fuses with the two polar nuclei, forming a triploid nucleus. The triploid nucleus later becomes the endosperm. The walls of the ovary develop into fruit.  

Similarities Between Male and Female Gametophyte 

• Male and female gametophyte are the two types of gametophytes produced by heterosporous plants. 
• They represent one of the two generations in the alteration of generations in plants.  
• Both are haploid and are derived from the corresponding spores. 
• They produce the corresponding gametes. 

Difference Between Male and Female Gametophyte 

Definition 

Male gametophyte refers to the life stage of heterosporous plants which produces male gametes while female gametophyte refers to the life stage of heterosporous plants which produces female gametes. This explains the basic difference between male and female gametophyte.

Derived from 

The microspore or pollen grain produces the male gametophyte while the megaspore produces the female gametophyte. This is a main difference between male and female gametophyte.

Origin 

Another difference between male and female gametophyte is their origin. Male gametophyte originates inside the microsporangium while female gametophyte originates inside the megasporangium. 

Number of Cells 

Number of cells and their functionability is the next major difference between male and female gametophyte. Male gametophyte has three cells while female gametophyte has eight cells. Furthermore, all the cells in the male gametophyte are functional while only two cells in the female gametophyte are functional.  

Growth Phase

We can say the growth phase also as another difference between male and female gametophyte. The male gametophyte has two phases of growth while the female gametophyte has a single phase of growth.

After Fertilization 

Male gametophyte disintegrates after fertilization while female gametophyte produces new structures after fertilization. This is yet another difference between male and female gametophyte. 

Fate 

Male gametophyte leaves the microsporangium while female gametophyte remains inside the megasporangium. 

Conclusion 

Male gametophyte is the haploid stage that produces male gametes. It derives from the microspore. Female gametophyte is the haploid stage that produces female gametes. It derives from the megaspore. Male gametophyte is inside the pollen grain while female gametocyte is inside the ovule. The main difference between male and female gametophyte is their structure and function. 

Reference:

1. Michael Borg, Lynette Brownfield, David Twell; Male gametophyte development: a molecular perspective, Journal of Experimental Botany, Volume 60, Issue 5, 1 April 2009, Pages 1465–1478, Available Here
2. Drews, Gary N., and Anna M.G Koltunow. “The Female Gametophyte.” The Arabidopsis Book / American Society of Plant Biologists 9 (2011): e0155. PMC. Web. 13 Sept. 2018, Available Here

Image Courtesy:

1. “Male Gametophyte Male Gametophyte Pinus Staminate Zoomed” By Iceclanl – Own work (CC BY-SA 3.0) via Commons Wikimedia 
2. “Angiosperm embryo sac diagram” By BlueRidgeKitties (CC BY 2.0) via Flickr