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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The neutral sporangia produce diploid swarmers which germinate to form sporophytes. In this article we will discuss about Ectocarpus. Some species like E. In physiologically anisogamous species, gametes from two filaments of different strains fuse. These diploid zoospores multiply only sporophytic plants and they do not play any role in alternation of generation.

This forms diploid, sporophylic plants. The number and shape of chromatophore varies with species. A large number of male gametes are attracted and cluster around female gamete to make clump formation Fig. The nature of growth varies with the region of plant body and also with species.

The zoospores of plurilocular and unilocular sporangia are identical in structure but zoospores of plurilocular sporangia are diploid and zoospores of unilocular sporangia are haploid. Reproductive Structures of Ectocarpus Algae. According to KnightSchussing and Kothbaouerrarely the zoospores released from unilocular sporangia, show pairing and fusion but the fate of such zygotes is not known.

In most species the erect threads exhibit diffuse growth. The sexual reproduction may be isogamous, anisogamous or oogamous.

Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top. Here’s how it works: Anisogamy is very common. In this article we will discuss about the life cycle of ectocarpus, explained with the help of suitable diagrams. The largest mega-gametangia represent oogonia and the smallest micro-gametangia represent antheridia Cydle.


The filament produced by the germination of haploid zoospore bears pluriloculcar reproductive structure which produces gametes, is the gametophyte, and its cells are haploid. No reduction division takes place during zoospore formation, hence all the zoospores are diploid.

Life Cycle of Ectocarpus (With Diagram) | Algae

The gametes are liberated in water through terminal or lateral pore in gametangium. They are commonly available in both tropical and temperate seas. In many species the terminal portion of a branch may end in a colourless hair with a basal meristem Fig. The diploid plants bear both unilocular and plurilocular sporangia.

The protoplast of each diploid uninucleate cell of the sporangium is transformed into a single biflagellate zoospore Fig. They may also taper into hairs. The cells are arranged in vertical row Fig. The protoplast of each diploid uninucleate cell of the sporangium cycoe transformed into a single biflagellate zoospore Fig. In lie forms the prostrate system is well developed and the erect system is reduced. The growth is apical in E.

It is known as clump formation. These zoospores are haploid, they withdraw flagella and attach to the substratum by their anterior ends. They are the most primitive of all the members of the class Phaeophyceae. The cells are arranged in regular rows.

The protoplast of each cubical cell in gametangium metamorphosis into single biflagellate pyriform gamete.

Most of the Ectocarpus species are anisogamous. The haploid plants bear plurilocular gametangia. Like unilocular sporangia, the plurilocular sporangia also develop from the terminal cells of the branchlets of diploid sporophytic plant. The diploid nucleus of zygospore divides mitotically during germination. In isogamous species the fusing gametes are morphologically and physiologically similar.


Further divisions are transverse and vertical in these cells to make hundreds of cubical cells arranged in transverse layers.

Life Cycle of Ectocarpus (With Diagram) | Phaeophyta

After sometime one male gamete fuses egg to make zygospore and other gametes detach themselves from female gamete. The zoospores remain inactive for seconds then become free and swim in water. The gametes are liberated in water through terminal or lateral pore in gametangium. It repeatedly undergoes transverse divisions to form a row of cells Fig.

But some are less active and become passive after a short time. The more active gametes are considered male.

Ectocarpus: Occurrence, Features and Reproduction

The cell which functions as sporangial initial Fig. Morphologically, haploid and diploid vegetative filaments are almost alike, but the cells of haploid filaments are comparatively shorter in length than cycoe diploid filaments. The anterior flagellum is longer, pantonematic and directed forward while the posterior is shorter, acronematic and directed backward Fig.

The zoospores remain motile for hours and then germinate into diploid thallus which later on bears unilocular and plurilocular sporangia.

The single nucleus of the young unilocular sporangium divides and redivides producing 64 nuclei. During warmer part of the year haploid filaments producing gametangia and gametes are developed.

This cell functions as sporangial initial Fig. This type of life cycle has a great resemblance with the life cycle of the green alga Ulva.