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 zoospores formed in unilocular sporangia are haploid and on germination form haploid gametophytic thalli. The sexual reproduction may be isogamous, anisogamous or oogamous.

The plurilocular gametangia and plurilocular sporangia are similar in structure and development. Some cells of the prostrate filament become active and form erect filaments. In India Ectocaupus is represented by about species. On germination it develops into a sporophytic 2n plant.

Sexual reproduction may be isogamous, anisogamous or oogamous type. It repeatedly undergoes transverse divisions to form a row of cells Fig.

Life Cycle of Ectocarpus (With Diagram) | Phaeophyta

Live the other hand, unilocular sporangium produces zoomeiospore through meiosis, followed by several mitotic divisions. No reduction division takes place during zoospore formation, hence all the zoospores are diploid. The medium sized meso-gametangia give rise to medium size gametes.


Answer Now and help others. Each unit then metamorphoses into a single, uninucleate 2n and biflagellate zoospore. A large number of male gametes are attracted and cluster around female gamete to make clump formation Fig. Though both are morphologically more or less alike, the gametes are slightly smaller in size than the zoospores.

Quick Notes on Ectocarpus (With Diagram) | Algae

While the one formed by the direct germination of the zygote bearing unilocular sporangia and plurilocular sporangia is the sporophyte having diploid cells. The gametangial initial divides transversely to form a row of cells. The zoospores formed cucle plurilocular sporangia are diploid and give rise to diploid sporophytic plants on germination.

Out of two flagella, posterior one is short and whiplash type i.

The cells are arranged in regular rows. On contact with suitable substratum, the zoospore withdraws its flagella and forms a new cell wall around it Fig. These plants are called gametophytic cycpe as on maturity they bear plurilocular gametangia.

Life Cycle of Ectocarpus (With Diagram) | Algae

The micro-and macrogametes after liberation fuse and form zygote, Fig. The physodes contain polyphenols, probably function as lysosomes. 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 India they are commonly found in the western coast.


Morphologically, haploid and diploid vegetative filaments are almost rctocarpus, but the cells of haploid filaments are comparatively shorter in length than the diploid filaments. The gametes are liberated in water through terminal or lateral pore in gametangium. In intercalary or trichothallic growth meristem is located at the base of a hair E.

The filament produced by the germination of haploid zoospore bears pluriloculcar reproductive structure which produces gametes, is the gametophyte, and its cells are haploid. Each zoospore is pyriform, uninucleate with two laterally inserted unequal flagella.

Life Cycle of Ectocarpus (With Diagram) | Phaeophyta

They germinate to produce new diploid sporophytic plant. Each nucleus of the sporganiuin gets surrounded by protoplast segment and ultimately transforms into zoospores Fig. Many transverse and vertical divisions result in formation of cubical cells arranged in transverse tiers Fig.

The egg and antherozoids produced by the mature mega-gametangia and micro-gametangia fuse to form zygospore. In Ectocarpus the sporophytic and gametophytic plants are morphologically similar hence there is isomorphic alternation of generation Figs. The micro-and macrogametes after liberation fuse and form zygote, Fig.