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In this article we will discuss about the asexual and sexual reproductive structure of ectocarpus.
Asexual Reproduction of Ectocarpus:
1. Reproduction is by asexual as well as sexual methods.
2. Asexual reproduction is with the help of zoospores.
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3. Zoospores are haploid as well as diploid.
4. Haploid zoospores are formed in unilocular sporangia while the diploid zoospores in plurilocular (neutral) sporangia.
5. Both the unilocular and plurilocular sporangia are formed on diploid asexual plants (Fig. 37).
Unilocular Sporangia:
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1. These are borne singly on lateral branches (Fig.37).
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2. Each sporangium is a stalked, globular or pear- shaped structure having dense cytoplasm with many chromatophores and diploid nucleus.
3. Diploid nucleus divides meiotically into many haploid nuclei (32-64), each of which changes into a zoospore.
4. Each zoospore is anuninucleate, small, pear-shaped and haploid structure with two laterally attached flagella. Zoospores develop into haploid sexual plant.
Plurilocular (Neutral) Sporangium:
1. These are also formed on diploid plants at the ends of small branches (Fig. 37).
2. These are elongated cone-like structures, made up of many small cubical cells or compartments arranged in vertical rows.
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3. Diploid nucleus of each compartment changes into a single diploid zoospore which again gives rise to diploid plant on germination.
Sexual Reproduction of Ectocarpus:
Most of the species are isogamous but some show clear anisogamy. Gametes are formed in the pluriloculargametangia, formed on the haploid, gametophytic or sexual plant.
Plurilocular Gametangium:
1. It is a sessile or shortly-stalked body.
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2. It is similar to the plurilocular sporangium in shape and structure.
3. Protoplast of each cubical compartment changes into a single uninucleate, biflagellate haploid gamete.
4. Gametes fuse and form the diploid zygote.
5. Diploid zygote germinates directly into a diploid plant which again bears unilocular and plurilocular sporangia.
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6. The plant shows clear isomorphic alternation of generations.
