Category: Biology Second Paper Lecture Sheet

Aplanosporangium is formed in the algal body in unfavorable environment. Non-flagellated cells are produced inside the aplanosporangium. These molecules are enveloped by the wall and become aplanospores. Spores germinate in favorable environment to form new filaments. Such as Vaucheria, Ulothrix, Microspora, Chlorella etc.

One or more cells of algae transform to form zoosporangium. The protoplast of zoosporangium divides to produce two or more zoospores. These zoospores have two or four flagella and are motile. However, a single zoospore with many flagella is produced inside the zoosporangium of algae of class Oedogoniales and family Vaucheriaceae. It is called synzoospore. These zoospores germinate and give rise to new algae. Such as Ulothrix, Chara, Vaucheria, Ectocarpus, Oedogonium etc.

1. Zoospore: One or more cells of algae transform to form zoosporangium. The protoplast of zoosporangium divides to produce two or more zoospores. These zoospores have two or four flagella and are motile. However, a single zoospore with many flagella is produced inside the zoosporangium of algae of class Oedogoniales and family Vaucheriaceae. It is called synzoospore. These zoospores germinate and give rise to new algae. Such as Ulothrix, Chara, Vaucheria, Ectocarpus, Oedogonium etc.
2. Aplanospore: Aplanosporangium is formed in the algal body in unfavorable environment. Non-flagellated cells are produced inside the aplanosporangium. These molecules are enveloped by the wall and become aplanospores. Spores germinate in favorable environment to form new filaments. Such as Vaucheria, Ulothrix, Microspora, Chlorella etc.
3. Autospore: Very small aplanospores are formed in the algal body similar to the mother cell. These spores are called autospores. Autospores germinate to form new plants. For example – Chlorococcus, Chlorella, Scenedesmus etc.
4. Pameloid: In extremely dry conditions, the protoplast of the algal body cell divides to form numerous daughter cells. These non-flagellated (aplanospore) germ cells are covered by a gelatinous membrane. This condition is called Pamela Dasha. Under favorable conditions the gelatinous coating dissolves in water flow and each cell transforms into a zoospore. Each zoospore gives rise to new algae. Such as Fucus, Sargassum, Chlamydomonas etc.
5. Hypnospore: Aplanospore stores a lot of food in harsh environment and is surrounded by a thick wall. It is called Hypnospore. Such as Ulothrix, Botrydium, Chlamydomonas, Vaucheria, Pediastrum, Sphaerella etc.
6. Endospore: Class Bacillariophyceae and some blue-green algae reproduce asexually by endospore formation. For example, Chaemaesiphon.
7. Axospore: Algae of Bacillariophyceae complete asexual reproduction by producing a special type of spore called axospores. Eg – Chaemaesiphon, Navicula etc.
8. Akinity: In unfavorable environment, one or more cells of some protozoan algae swell to store large amounts of food and develop into resting spores covered by a thick wall. These cells are called akinites. Each actinomycete germinates into a new alga in a favorable environment. Such as Nostoc, Oedogonium, Gloeotrichia, Oscillatoria, Pithophora, Ulothrix, Revularia, Cladophora etc.

Protonema is formed from the rhizoids of some algae. New algae grow from these protonema. Like- Chara, Nitella etc.

White matter accumulates in the body of some algae and forms a star-shaped organ. They are called starch stars or amylum stars. Later new algae are born from the starch star. Like Chara, Botrydium etc.

In unfavorable environment, one or more cells of some protozoan algae swell to store large amounts of food and develop into resting spores covered by a thick wall. These cells are called akinites. Each actinomycete germinates into a new alga in a favorable environment. Such as Nostoc, Oscillatoria, Pithophora, Ulothrix, Gloeotrichea, Revularia etc.

Tuber or bulbil is produced by the accumulation of food above and below the rhizoid in some algae. These separate from the mother body and form new algae. Like- Chara, Cladophora, Botrydium etc.

In unfavorable environment hormogonium of algae is covered by thick wall to form hormocyst. Under favorable conditions, hormocysts germinate and give rise to new algae. Eg Nostoc, Oscillatoria etc.

Trichrome of blue-green algae breaks down to form hormogonia. The hormogonium is covered by a thick wall to form the hormocyst. New algae are produced from hormogonia in favorable conditions. Eg Nostoc, Oscillatoria etc.

In favorable environment, the algae grows in size by taking food and outgrowths form from the side of the body. A bud or bud is then produced from the subgrowth and the bud separates from the mother body to give rise to new algae. Eg- Protosiphon.