ECTOCARPUS LIFE CYCLE PDF

Botany 9 Comments Occurrence Ectocarpus is a brown alga. It is abundantly found throughout the world in cold waters. A few species occur in fresh waters. The plant grows attached to rocks and stones along coasts. Some species are epiphytes on other algae like members of Fucales and Laminaria.

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Botany 9 Comments Occurrence Ectocarpus is a brown alga. It is abundantly found throughout the world in cold waters. A few species occur in fresh waters. The plant grows attached to rocks and stones along coasts. Some species are epiphytes on other algae like members of Fucales and Laminaria.

Ectocarpus fasciculatus grows on the fins of certain fish in Sweden. Ectecarpus dermonemcnis is endophytic. Ectocarpus carver and Ectocarpus spongiosus are free- floating. Vegetative Structure Structure of thallus Genetically the thalli may be haploid or diploid. But both the types are morphologically alike. The thallus consists of profusely branched uniseriate filaments.

It shows heterotrichous habit. There are two systems of filaments. These are prostrate and projecting system. The filaments of the projecting system arise from the filaments of prostrate system a Prostate system: The prostrate system consists of creeping, leptate, irregularly branched filaments. These filaments are attached to the substratum with the help of rhizoids. Prostrate system is poorly developed in free floating species. It consists of well branched filaments.

The main axis and the branches of the projecting system are uniseriate. In this case, rens are joined end to end in a single series. The branches terminate into an acute point to form a hair.

In some species the older portions of main axis are ensheathed corticated. This sheath is formed of a layer of descending rhizoidal branches.

They are cylindrical or rectangt lar and uninucleate. Algin and fucoidan are also present in the cell wall. These are characteristic gelatinous substances of tne walls of brown algae. The chromatophores may ribbon-like with irregular outline or disc- shaped.

The dominant of Ectocarpus is fncoxanthin. It gives this algae golden brown colour. The other photosynthetic iigments are chlorophyll-a, -c, beta. All other eukaryotic organelle are present. It is called trichothallic meristem. It increases the length of the terminal hair and vegetative cell of the branch.

This growth is called trichothallic growth. Asexual reproduction The asexual reproduction takes place by the formation of biflagellate zompores. These zoospores may be haploid produced in one-celled unilocular sporangia. Both kinds of sporangia are present on the same diploid sporophyte plant.

The sporangia are borne terminally and singly on lateral branches. Ile sporangial initial enlarges in size. It becomes globose or ellipsoidal. The number of chromatophores also increases in it.

The nucleus of the sporangium divides meiotically to produce four haploid nuclei. These nuclei undergo repeated mitotic divisions to produce daughter nuclei.

The cytoplasm of the lporangium divides. A small amount of cytoplasm surrounds a nucleus and a thromatophore to produce daughter protoplasts. Each daughter protoplast metamorphoses into a meiozoospore produced by meiosis. Meiozoospore is pyriforrn and biflagellate.

The flagella are laterally inserted and are of unequal size. The larger one directed forward and the smaller one is directed backward. An apical pore is formed in the gelatinous mass of sporangia. The meiozoospores come out of this pore. These are separated from each other after few moments. They swim freely in all directions. A new sporangium may be nroduced within the old sporangial wall after the liberation of zoospores.

These are elongated, cone-like multicellular structures. These also develop from a terminal cell of a short lateral branch. The sporangial initial enlarges in size. It undergoes repeated transverse mitotic divisions. It produces a vertical row of :ells. These cells then divide by vertical and transverse divisions repeatedly.

They form a cone-like structure. This cone consists of hundreds of small cubical cells. These cells are arranged in transverse tiers. Each cell represents a sporangium. The protoplast of each cell metamorphoses into a single mitozoospore produced by mitosis. The mitozoospore is pear-shaped, diploid and biflagellate. The flagella are of unequal size Ind are laterally inserted.

The mitozoospores are liberated through a terminal or a lateral pore. This pore is formed in the wall of the sporangium. Fig: Development of PI uri locu lar sporangia Germination of Zoosporesa Germination of meioszoospores: The zoospores formed in unilocular sporangia meioszoospores swarm for scinetime.

They withdraw their flagella and secrete a membrane around then. They germinate and form a small germ tube. This tube is separated prom the meiozoospore cell through a septum. This germ tube divides and redivides. It forms the prostrate system of plant.

The xojecting system arises from the filaments of the prostrate system. The new plant form is haploid. Therefore, it isgametophyte. The meiozoospores develop into a gameiophytic olant. Therefore, these spores are also called as gonozoospores. They develop in the same manner as the meiozoospores. But they are diploid. Therefore, they develop into a diploid sporophyte.

Therefore, the mitozoospores are also called as neutral spores. They are. Majority of the species are isogamous and homothallic. Some species are anisogamous. Ectocarpus secundus is heterothallic and anisogamous. The gametes are produced in plurilocular gametangia. These gametangia are many-celled, elongated, and sessile or shortly stalked con i :al structures. These gametangia are produced on the haploid plants developing from the meiozoospores. The development of gam ztangia is similar to that of plurilocular sporangia.

These develop from terminal cell of a lateral branch. The gametangial initial gets inflated. It divides mitotically by repeated transverse divisions. It produces a vertical row of flat cells. Kingdom Protista: Algae These cells undergo repeated vertical and transverse divisions.

They form many hundred small cubical cells. These cells are arranged in transverse rows.

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Quick Notes on Ectocarpus (With Diagram) | Algae

Both sporangia and gametangia are occasionally found on the same plant. Genus Ectocarpus of Phaeophyta: This is one of the best-known brown algae containing many species. It is a marine alga of world-wide distribution being abundant particularly along the Atlantic Coast but rather scarce along the Pacific Coast. The ultimate branch-lets of the erect portion are generally attenuated to an acute point Fig.

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Ectocarpus Occurrence, Structure ,Reproduction & Division

Featured Presentations Search Results Ectocarpus siliculosus Filamentous, cosmopolitan brown alga mostly from temperate seas One of the best-studied seaweeds The first fully-sequenced multicellular Benthic fauna. A Macrocystis stipe, cross section. D Fucus. A Fucus. Chlorella algae are small, spherical, unicellular, nonmotile, asexual reproducing green algae. PowerPoint PPT presentation free to download Most are single-celled, but some are composed of hundreds of cells colonies

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Life Cycle of Ectocarpus (With Diagram) | Algae

Genus: Ectocarpus Occurrence of Ectocarpus: Ectocarpus is word-wide in distribution particulary in colder seas and Polar Regions. Ectocarpus is very common on sea shore of Atlantic Ocean. Ectocarpus is found attached on sea rocks. Some species of Ectocarpus are epiphytic e. In India Ectocaupus is represented by about species. Thallus Structure: The plant body is mostly typically heterotrichous and differentiated into a creeping or prostrates system and b projecting an erect system. In some species one of the two systems may be reduced.

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