Life cycle of Ectocarpus siliculosus. Both Ectocarpus sexual and asexual life cycles are displayed. Gametes (right side) released from WT male gametophytes . The life history of Ectocarpus fasciculatus var. refractus (Kiitz.) Ardis. from Roscoff , France, has been studied in culture. This species proved to be the sporophytic. the sexual pheromones and infection of Ectocarpus by viruses. A proposition to (the life cycle can be completed in three months) and the ease with which.

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Ectocarpus – Wikipedia

This is one of the best-known brown algae containing many species. Though both are morphologically more or less alike, the gametes lif slightly smaller in size than the zoospores. These diploid zoospores multiply only sporophytic plants and they do not play any role in alternation of generation.

The more active ones cluster around the relatively passive one and fix themselves to it by their forwardly directed flagella. These zoospores are haploid, they withdraw flagella and attach to the substratum by their anterior ends.

The asexual reproduction takes places with the help of biflagellate zoospores. Out of two flagella, posterior one is short and whiplash type i.

Reduction division takes place during the production of zoospores in the unilocular sporaxlgia which behave as zoosporangia. The medium sized meso-gametangia give rise lice medium size gametes. These are unilocular sporangia and pleurilocular or neutral sporangia Fig. The cell contains a few parietal band shaped chromatophores with irregular branches E. The zoospores formed from plurilocular sporangia are alike with the zoospores i. These two types of zoosporangia may be produced on the same plant or on different plants.


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The zygospore germinates after days. This cell functions as sporangial initial Fig.

The zoospores formed in plurilocular sporangia are diploid and give rise to diploid sporophytic plants on germination. The sexual reproduction is both ectlcarpus and anisogamous type.

The cells are arranged in vertical row Fig. Each zoospore is pyriform, uninucleate with two laterally inserted unequal flagella.

They do not fuse but develop new plant parthenogenetically. The protoplast of each cubical cell in gametangium metamorphosis into single biflagellate pyriform cycpe.

The cells are generally rectangular, uninucleate and the nucleus is placed in the region of the central vacuole, suspended by protoplasmic threads. The sexual reproduction may be isogamous, anisogamous or oogamous.

They remain motile for about 30 minutes. The individual cell uninucleate and contains plate-like or band-shaped chloroplast with or without pyrenoids. The zoospores remain motile for hours and then germinate into diploid thallus which later on bears unilocular and plurilocular sporangia.


Zoomeiospores on germination develop gametophytic plants. The erect system shows intercalary, diffuse or trichothallic growth, whereas it is apical in prostrate system.

The smaller gametes are produced in micro-gametangia and the larger are produced in bigger mega-gametangia. The diploid plants bear both unilocular and plurilocular sporangia.

Ectocarpus: Occurrence, Features and Reproduction

Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top. This multicellular structure is called plurilocular sporangium. Then vertical divisions start in all the cells starting with the median cells of the row.

In many species the terminal portion of a branch may end in a colourless hair with a basal meristem Fig.

Life Cycle of Ectocarpus (With Diagram) | Algae

It repeatedly undergoes transverse divisions to form a row of cells Fig. They named the plurilocular reproductive structures as neutral sporangia. This type of life cycle has a great resemblance with the life cycle of the green alga Ulva.

The more active gametes are considered ectocwrpus. In epiphytic forms the prostrate system is well developed and the erect system is reduced.

Here’s how it works: The unilocular sporangia develop from the apical cell of short lateral branches Fig.