Photosynthetic Protists - Chrysophytes
Description:
The general characteristics of chrysophytes are as follows −
Habits and Habitats
Occur in all aquatic and moist terrestrial habitats.
May be free floating or bottom dwellers.
Free floating forms is able to remain suspended on the surface of water by mucilage secretion and presence of light weight lipids.
Show gliding movements.
Pile up at the bottom of water reservoir and form big hips called diatomite or diatomaceous earth.
Reserve food is in the form of oils and leucosin.
Structure
Body is covered by transparent siliceous shell known as frustule.
They are microscopic and variously coloured.
They do not possess flagella except in the reproductive stage.
They have a large central vacuole and single large nucleus.
Presence of photosynthetic pigments chlorophyll a and chlorophyll c.
Reproduction
Binary fission is one of the Common mode of reproduction.
Spores are formed in some case.
Sexual reproduction may also occur in some cases.
Economic importance of Diatoms
Important photosynthesisers.
Diatomite deposits are often accompanied by petroleum fields. Most of the petroleum today is probably due to decayed bodies of the past diatoms.
They are porous and chemically inert hence used for filtration of sugar, alcohols etc.
Used to make sound proof rooms.
Used as pollution indicators.