Zygospores are spores formed in some fungi such as Rhizopus. The two units (male and female gametes) from two separate individuals unite by fusion of their cytoplasm, followed by the union of their nuclei. The three common modes of reproduction for algae includes asexual, sexual and vegetative reproduction. In the higher form of algae, in addition to vegetative reproduction i.e., by separation of parts of the individual (fragmentation) both asexual and sexual reproduction in algae is common. Image Guidelines 5. Each such spore is surrounded by a wall. Aplanospores are non- motile spores. The asexual spores may be of various types: These are motile naked spores provided with two, four or many flagella and called as bi-, quadri- or multiflagellate zoospores, respectively. In this method the vegetative cell divides mitotically into two daughter cells, those finally behave as new individual. The vegetative reproduction in algae is of the following types: It is the simplest method of reproduction. Without taking rest, the spores germinate directly and develop into a new plant, e.g., Dermocarpa (Fig. For example, some plants, fungi, and algae. The motile gametes taking part in fusion may either differ in size (morphological anisogamy) or physiological behaviour (physiological anisogamy). In vegetative reproduction, the thallus gets separated from the parent and develop a new daughter cell. Here the successive generations of divided cells are gelatinized and a thick mucilaginous envelope develops, e.g., Chlamydomonas, Ulothrix, etc. (b) The bright light is the major factor for the production of the gametes. They are found in Rhodophyceae. Plagiarism Prevention 4. Some seaweed species have gas-filled bladders (pneumatocysts), which keep photosynthetic parts of the algal thallus floating on or near the surface of the water. In this phenomenon, the fusion of the daughter protoplasts or of the divided nuclei of a cell without liberation takes place. There are two main types, i.e., (i) isogamy and (ii) heterogamy. In this type, any vegetative part of the thallus develops into new individual. Depending on the structure, physiological behaviour and complexity of sex organs, sexual reproductions are of the following five types: In this process the fusing gametes are developed from the same mother cell and after fusion they form zygote. Each such bulbil may develop into a new plant. These spores aggregate in groups and develop new colonies, e.g., Chamaesiphon (Fig. Usually the gametes taking part in fusion come from two different individuals or filaments, sometimes these gametes come from two different cells of the same filament. The diploid nucleus of a tetrasporangium divides meiotically to form four haploid nuclei which — with little amount of protoplasm — are developed into four tetraspores. Sexual. 3.18). The zoospores are liberated either by the disintegration of the zoosporangial wall or by the formation of an apical pore on the zoosporangium. In filamentous and multicellular forms, the algae might get broken by accident into small pieces, 1each building up into a new one. There may be single zoospore (e.g., Oedogonium) or many zoospores (e.g., Cladophora) per zoosporangium. They resemble in shape to mother cell except in size. Vegetative 2. Each spore gives rise to a new plant, e.g., many members of Rhodophyceae (Bangia, Porphyra, Porphyridium, etc). The trichomes of blue-green algae break up within the sheath into many-celled segments called hormogonia or hormogones. Fission. 3.17G). Male gametes develop within antheridium, whereas the female gamete within the oogonium, e.g., Oedogonium, Vaucheria, Chara, Laminaria, Sargassum, Polysiphonia, Batrachospermum etc. Each hormogone develops into a new plant, e.g., Oscillatoria, Nostoc, etc. The zoospores are formed from certain older cells of the filaments. Almost all prokaryotes undergo a type of asexual reproduction called binary fission. With the onset of favourable condition the hypnospores either directly germinate into a new individual or their protoplasts may form zoospores. They are just like aplanospores except that they are smaller in size. Welcome to BiologyDiscussion! Hormogonia are commonly found in Nostoc, Oscillatoria, Cylindosporium etc. During asexual reproduction, the parent cell divides into two or … The reproduction of algae can be discussed under two types, namely asexual reproduction and sexual reproduction. Asexual reproduction involves the formation of certain type of spores — either naked or newly walled. There is several process of Asexual Reproduction like fission, budding, fragmentation, regeneration and … Usually develop on the rhizoids of Chara are called bulbils. Vegetative reproduction is the propagation through the vegetative parts of the plant body. Algae live with fungi in lichens.. This is exclusive type of reproduction in Pleurococcus, some desmids, diatoms, Euglena, etc. Spore formation is the most common asexual method of reproduction in: A. Protozoa. 3.17B) and multiflagellate zoospores are found in Oedogonium (Fig. Sometimes they are formed in chains. For example, he was a FUN-GUY (fungi), so it's … Small bud-like structures. Diatoms have a nucleus, cytoplasm, vacuoles, and chromatoplasts as cell components. Asexual reproduction is the production of progeny without the union of cells or nuclear material. The several types of algal colonies are thallus, slime coat, filament, branched filaments, holdfasts, sessile algae, air bladders. Due to deposition of haematochrome pigment in their walls, the hypnospores of Chlamydomonas nivalis are red in colour. A fungus? In this case, the male antherozoid fuses with the female egg. The aplanospores develop in unfavourable conditions. This type of vegetative reproduction is commonly met within filamentous forms, e.g., Ulothrix, Spirogyra, etc. After liberation the zoospores swim for a while, then withdraw their flagella, encyst and ultimately germinate into new plants. The zoospores are always motile. Explain its main characters. Each zoospore has a chloroplast and an eye spot. Common Types of Algae Identification and Sustainable Management. When detached from the plant body, they grow into new plants. These structures are called amylum stars (Fig. It may take place by any one of the following ways: Fission:It involves simple mitotic division resulting in the formation of two daughter cells.