Spirogyra (Chlorophyta) | General Cell structure of Spirogyra | conjugation process in spirogyra | Dr Malik

 Spirogyra 

(Chlorophyta)

General Cell Structure of Spirogyra

• Spirogyra is a filamentous algae. 
• It forms long and thin strands of cells in vast numbers. 
• They are very familiar with green, slimy ‘blanket weed’ in ponds. 
• The filaments of Spirogyra formed an extensive chain of identical cells. 
• Each cell contains a chloroplast, a nucleus, a cytoplasm, and a vacuole enclosed in a cellulose cell wall.
• Spirogyra is a green algae having a filamentous structure, which measures about 10-100 micrometers in width. 
• They contain chlorophyll and make their food by photosynthesis. 
• The growth of Spirogyra can be observed by the increase in the length of the filament of Spirogyra. 
• The Spirogyra increases its length by both sexual and asexual means. 
• When the filament breaks and it results in the formation of new spirogyra cells then this form of reproduction is called asexual reproduction.
• Conjugation is an example of sexual reproduction in spirogyra.

Conjugation. 

• The cells of mature Spirogyra develop a tubular structure out of its cell. 
• This tubular structure is called a conjugation tube.
• The tubes join with another cell of Spirogyra and make a passage between the cell and its partner cell. 
• The chloroplasts and other structures become less distinct and the cytoplasm pulls free from the cell wall to form a rounded structure. 
• The cytoplasmic contents of the cells now act as gametes. 
• The gametes of one filament then pass through the tubes (conjugation tubes) and fuse with the gametes of the cells of the adjacent filament and the nuclei fuse to form a zygote.
•  A resistant wall develops around the zygote to form a spore. 
• When the cell walls of the filament break down, the spore is released and sinks to the bottom of the pond. 
• The spore can survive adverse conditions such as low temperatures and a shortage of light.
•  Under favorable conditions, the spore wall breaks and a new spirogyra filament grows out.