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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So, each small cubical cells of plurilocular sporangium contains single diploid nucleus. In physiologically anisogamous species, gametes from two filaments of different strains fuse.

Life Cycle of Ectocarpus (With Diagram) | Algae

The zoospores remain inactive for seconds then become free and swim in water. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. The zoospores formed ljfe unilocular sporangia are haploid and on germination form haploid gametophytic thalli. Though both are morphologically more or less alike, the gametes are slightly smaller in size than the zoospores.

The haploid plants bear plurilocular gametangia. Plant body is filamentous, much branched and heterotrichous, having basal rhizoids and well-developed branched erect system.

Ectocarpus: Occurrence, Features and Reproduction

Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top. The plurilocular gametangia are either sessile or stalked and vary in shape from ovate to siliquose.

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It takes place by zoospores. Each unit then metamorphoses into a single, uninucleate 2n and biflagellate zoospore. Plant Body of Ectocarpus 3. In Ectocarpus the sporophytic and gametophytic plants are morphologically similar hence there is isomorphic alternation ectocarpuus generation Figs.

The gametes are produced inside the plurilocular gametangia, developed on haploid plants. Plants are usually attached to other submerged plants, sometimes to stones or similar other objects.

Here’s how it works: The zygospore germinates after days. The formation of unilocular and plurilocular sporangia is affected by environmental conditions like temperature and salinity of water. In a limited number of species growth is trichothallic, during which intercalary meristems are found at the base of the hairs.

The unilocular zoosporangia form haploid zoospores and the plurilocular ectocarpjs form diploid zoospores. While the one formed by the direct germination of the zygote bearing unilocular sporangia and plurilocular sporangia is the sporophyte having diploid cells.

The prostrate system serves the function chcle anchorage with the substratum or on other plants and the erect system is photosynthetic and bears reproductive organs. On germination it develops into a sporophytic 2n plant. The female gamete after liberation secretes a volatile sexual attractant sirenine.

Anybody can ask a question Anybody can answer The best answers are voted ectocarpks and rise to the ectoccarpus.

Occurrence, Structure and Reproduction With Diagrams. The number and shape of chromatophore varies with species. The asexual reproduction takes places with the help of biflagellate zoospores. The zoospores remain motile for hours and then germinate into diploid thallus which later on bears unilocular and plurilocular sporangia. This forms diploid, sporophylic plants. In some species, the older portions of the main branches are corticated by a layer of descending rhizoidal branches.


Galls are formed in Laminaria and Cystoseria due to the presence of E. Occurrence, Structure and Reproduction. It repeatedly undergoes transverse divisions to form a row of cells Fig. Anisogamy may be of two types: The asexual reproduction takes places with the help of biflagellate zoospores.

The apical cell enlarges and functions as sporangial initial. No reduction division takes place during zoospore formation, hence all the zoospores are diploid.

Liberation of the swarmer is through a pore on the cell wall Fig. The physodes contain polyphenols, probably function as lysosomes.

Both the main axis and branches are uniseriate monosi- phohousbut the lower part may become multiseriate polysiphonous yccle to longitudinal division e. These diploid zoospores multiply only sporophytic plants and they do not play any role in alternation of generation. The unilocular sporangia develop haploid zoospores i. These gametes are morphologically identical but one is less active, becomes passive after a short period and behaves as female gamete.

In most species the erect threads exhibit diffuse growth. Further divisions are transverse and vertical in these cells to make hundreds of cubical cells arranged in transverse layers.