The vegetative body structure of spirogyra
A) External features
- The vegetative body of Spirogyra is unbranched and filamentous.
- The plant body is long, slender and multicellular.
- Numerous elongated and identical cells are arranged vertically in the filamentous body
- At the posterior end of the filament, there is a unicellular compressed part, called holdfast or hapteta by which the plant body remains attached with any substratum.
B) Cell wall
- Cell wall consists of three layers of which inner two layers are made of pectose and the outer layer is composed of cellulose
- The filament is usually surrounded by a membrane made of mucilage
Fig: Structure of Spirogyra
Following parts are present in protoplasm:
- Plasma membrane: It is situated just beneath the cell wall. It covers the inner matters of the protoplasm.
- Cytoplasm: It is situated inside the cell wall, very close to the plasma membrane.
D) Cell vacuole
Each cell has a large vacuole placed at the center.
Each all contains a single nucleus. It remains suspended within the cytoplasm with the help of some cytoplasm strains.
Chloroplasts of this all are long and flattened as tape. They are arranged spirally around the space. A number of chloroplasts present in each cell depend on the bests of its species. Usually, the number of chloroplasts may vary from one to seven.
- Some silvery granules present in each chloroplast are called pyrenoids
- Plenty of protein piles up in the pyrenoids
- Starch is deposited as recent food around the pyrenoids.