Difference Between Homosporous And Heterosporous Pteridophytes With Examples

by

Homosporous Pteridophytes

Hemosporous life occurs in nearly all bryophytes and in most pteridophytes (lower vascular plants). It is characterized by morphologically identical spores that germinate to produce bisexual (both male and female) gametophytes in pteridophytes but either bisexual or more usually, unisexual (either male or female) gametophytes in bryophytes.  Each mature gametophyte bears gametangia (sex organs) that produce gametes. Each antheridium (male gametangium) forms many motile flagellate sperm and each archegonium (female gametangium) forms one nonmotile egg. Fusion of an egg and sperm (syngamy) creates a zygote and restores the 2n ploidy level.

Characteristics Of Homosporous Pteridophytes

  • Homosporous Pteridophytes are pteridophytes that produce only one type of spores that are not separated by sex. The spore contains both male and female parts.
  • Homosporous pteridophytes produce only one type of spores which are small in size.
  • Only one type of sporangia occurs in Homosporous pteridophytes.
  • Homosporous pteridophytes produce only one type of gametophyte containing both male and female parts.
  • In homosporous pteridophytes, spores germinate in soil and produce independent gametophyte. 
  • Examples of Homosporous pteridophytes are lycopodium, Equisetum, clubmoss and puzzlegrass.

Heterosporous Pteridophytes

A Heterosporous life occurs in some pteridophytes and in all seed plant.  It is characterized by morphologically dissimilar spores produced from two types of sporangia: Microspores or male spores and megaspores (macrospores) or female spores. In pteridophytes, megaspores are typically larger than microspores but the opposite is true in most seed plants.

The spores produce two types of gametophytes: each microspore develops into a microgametophyte (male gametophyte) which ultimately produces male gametes (sperm) and each megaspore produces a megagametophyte (female gametophyte) which ultimately produces female gametes (eggs). Fusion of an egg and a sperm creates a zygote and restores the 2n ploidy level.

Characteristics Of Heterosporous Pteridophytes

  • Heterosporous pteridophytes are pteridophytes which produce two types of spores separated by sex.  Male and female parts can be clearly distinguished.
  • Heterosporous pteridophytes produce two types of spores; the small microspores and the large megaspores. 
  • Two types of sporangia occur in heterosporous pteridophytes, that is microsporangia and megasporangia.
  • Heterosporous pteridophytes produce two types of gametophytes, that is, male gametophytes (microspore) and female gametophyte (magaspores).
  • In Heterosporous pteridophytes, spores germinate within sporangia and produce dependent gametophyte. 
  • Examples of Heterosporous pteridophytes are Selaginella, Marselia and Salvinia.

Between Homosporous And Heterosporous Pteridophytes In Tabular Form

BASIS OF COMPARISON HOMOSPOROUS PTERIDOPHYTES HETEROSPOROUS PTERIDOPHYTE
Description Homosporous Pteridophytes are pteridophytes that produce only one type of spores that are not separated by sex. The spore contains both male and female parts.   Heterosporous pteridophytes are pteridophytes which produce two types of spores separated by sex.  Male and female parts can be clearly distinguished.  
Spores Homosporous pteridophytes produce only one type of spores which are small in size.   Heterosporous pteridophytes produce two types of spores; the small microspores and the large megaspores.   
Types Of Sporangia Only one type of sporangia occurs in Homosporous pteridophytes.   Two types of sporangia occur in heterosporous pteridophytes, that is microsporangia and megasporangia.  
Gametophyte Homosporous pteridophytes produce only one type of gametophyte containing both male and female parts.   Heterosporous pteridophytes produce two types of gametophytes, that is, male gametophytes (microspore) and female gametophyte (magaspores).  
Germination In homosporous pteridophytes, spores germinate in soil and produce independent gametophyte.    In Heterosporous pteridophytes, spores germinate within sporangia and produce dependent gametophyte.   
Examples Examples of Homosporous pteridophytes are lycopodium, Equisetum, clubmoss and puzzlegrass.   Examples of Heterosporous pteridophytes are Selaginella, Marselia and Salvinia.  

Similarities Between Homosporous And Heterosporous Pteridophytes

  • Both have a dominant sporophytic generation
  • Both types develop into gametophytes
  • In both homosporous and Heterosporous pteridophytes, the gametes obtain the nutrition from the saprophyte.