Bryophyta (plant kingdom )

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Bryophyta


  • Body differentiation exists:-
    They have stem-like and leaf-like structure 
  • These are known as plant amphibians because even if they live in soil but they need water to complete their life cycle. water is something which is mandatory for them. 
  • They are mostly found in moist hilly areas
  • the specialized vascular tissue is  absent in them 
  • They play a very significant role in preventing soil erosion
  • They have hidden reproductive system-cryptogamae
  • Example; Mosses, hornworts, liverworts

Structure 


  • Here body differentiation exists 
  • They are erect with unicellular/ multicellular rhizoids (Rhizoids: -Hair-like structures from the lower epidermal cells  of bryophytes ) 
  • There are no true roots/stem/leaves 

Reproduction

Asexual reproduction:-
  • They reproduce asexually through fragmentation
  • Spore formation
Sexual reproduction:-
  • Gametophyte (plants which produce gametes )
  • Male gamete - Antherozoid ( They are motile )
  • Female gamete- Egg (nonmotile)
  • Male sex organ: Antheridium
  • Female sex organ: Archegonium
  • Water carries the male gamete to the female gamete as we know male gametes are motile but the female gametes are non-motile. When male gamete reaches the female gamete fusion will take place as a result of fusion zygote will be formed. Now, this zygote will grow to form a structure known as sporophyte. Now, these sporophytes will produce spores and these spores will grow to form a new plant. 

Significance

  • They are the source of food for other animals 
  • They prevent soil erosion
  • They help in Rock decomposition
  •  They help packing materials 

Subclassification of bryophytes

LIVERWORTS:
  • They prefer moist & shady habitats 
  • Their plant body is thalloid:-
    Stem-like structure
    Tiny leaf-like  structures 
  • There are two types of liverworts:-
    Thalloid liverworts
    Leafy liverworts 
  • Examples: Merchantia,  Riccia, Porella

Liverworts: asexual reproduction

  • Fragmentation of thalli ( plural of thallus )
  • Gammae formation 
  • Gammae:-
    propagative structures in thallose liverworts
    Green, multicellular asexual bonds

Liverworts: sexual reproduction

  • Fusion of gametes 
  • Male & female organs can be on same or different thalli 
  • Here haploid gametophyte is the dominant phase of life cycle    

Sporophyte



  • It is the diploid stage 
  • It develops from the zygote 
  • It begins to grow on out on top of the archegonium on the female gametophyte plant  
  • It consists of 3 structures:-
    Foot- It anchors to gametophyte
    seta- Long erect stalk : It transfers water and nutrients from gametophyte
    Capsules - spores are produced here 

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