The plant body is diploid except the antherozoids and eggs. • Fertilisation. After fusion zygote is formed. Sargassum contains higher amounts of protein essential Sketch, label and describe T.S. 1A–C).. 5. 13. Every stage of development in both structures is the same, from the appearance of the similar initial cells to the development of paraphyses in the cryptostomata and sexual organs in the conceptacle. 4.Sketch label and describe female conceptacle of Sargassum. Scytosiphon sp. Asexual reproduction is absent. 3.122). Like antheri­dium, oogonium also develops from the basal fertile layer of the conceptacle (Fig. It reproduces by both vegetative and sexual means. It serves the function of anchorage, photosynthesis, storage, conduction and support. • Development of sex organs. Lamanaria 3 cell layers (medulla, cortex, meristoderm) Lithophyllum imitans. 3.117A). %���� 3.120C). Due to rapid growth of the stalk cell, the antheridium becomes pushed at one side (Fig. Welcome to BiologyDiscussion! Sargassum,section Malacocarpicae,sous-section Cymosae. It is generally of circular in outline and differentiated into three regions: outer meristoderm, middle cortex and innermost medulla (Fig. The zygote then divides transversely and forms lower and upper cell. Answer Now and help others. endobj Oogonia and antheridia are borne in unisex­ual conceptacles, those remain embedded in receptacles. ... but with both conceptacle types co-occurring in the same receptacles. 3.120). :�h7b�.����jq �;(�GP"�i��8�m �d��(66d�q��Y� ͇divN�����#8S; ��ޡ��άÎ~�gF���P3&|��P�)�(˙ It bears long shoots of unlimited growth (primary laterals), leaves (secondary late­rals), air bladders and receptacles. The remaining antherozoids get separated and gradually dege­nerate, Initially after fertilisation both the nuclei remain side by side (Fig. 4. In homothallic or monoecious species the male conceptacle and female conceptacles are produced on same receptacle, but antheridia and oogonia are not produced in same conceptacles. The conceptacle ini­tial then undergoes mitotic division and by oblique septation it forms upper elongated tongue cell and lower broad basal cell (Fig. Apical growth takes place by a three-sided apical cell. The antheridial cell develops into an antheridium (Fig. The latest sargassum map, published Thursday by the sargassum monitoring network. Later on only one penetrates the oogonial wall. This is a question and answer forum for students, teachers and general visitors for exchanging articles, answers and notes. The cells are smaller in size than meristoderm. The mature antheridium (Fig. Sargassum heterophyllum reproductive morphology. Disclaimer Copyright, Share Your Knowledge Botany, Algae, Phylum Heterokontophyta, Classes, Phaeophyceae, Sargassum. 3.119A). The more abundant female conceptacles are usually almost entirely filled by a maximum of 3--4 rounded oogonia. In dioecious plants the male and female conceptacles are produced on separate male and female plants. The free floating members like S. hystrix and 5. natans, multiply only by this method. 3.116). The conceptacle and cryptostoma are undoubtedly homologous structures. Many thread like filaments also develop from the basal cells of the conceptacle which are also called paraphyses (Fig. It is found in tem­perate, subtropical and tropical regions of both northern and southern hemispheres. Which organelle is known as “power house” of the cell? The plant body is diploid and differentiated into root, stem and leaf-like structures. The cells of the wall have many chromatophores. Share Your PPT File. 2. The oogonial initial under­goes transverse division and forms lower small stalk cell and upper large oogonial cell (Fig. Due to death and decay of the older part, the younger region gets separated. Plant Body of Sargassum 3. 12. Vegetative reproduction takes place by frag­mentation. Our mission is to provide an online platform to help students to share notes in Biology. 3.120B). The antherozoids and eggs i.e., the gametes, represent only the haploid (n) stage. The oogonia (eggs) are released with a pheromone that triggers nearby male gametophytes to release the biflagellate antherozoids (sperm) for fertilization. The spores develop into haploid male or female gametophytes, which eventually produce the sexual gametes. Like the outer layer this layer also stores food material. The Female Conceptacle and Young Sporeling of the Four New Zealand Species of Carpophyllum By Margaret Naylor, Otago University [Read by title before Otago Branch on July 14, 1953; received by Editor July 27, 1953.] Fertilization is internal, as the egg is not come out from the oogonium. Occurrence of Sargassum 2. The main axis i.e., stem is vertically elonga­ted and differentiated into nodes and inter­nodes. Share Your Word File �@�G�@��0�w��]��d:�� ���Z'䃴�M����ѱ��/���x������iWY+\�j���S�C�ӆ>��x�;���?��w�YZ�`���*��. Since out-put of eggs is extremely low, 4 - 6 per female conceptacle, <i>Sargassum</i> sp. The eastern Pacific population has both male and female gametes on a single individual and is capable of self-fertilization. 2013)(1). Thousands of new, high … Before sharing your knowledge on this site, please read the following pages: 1. The antheridia are developed from the inner fertile layer of the antheridial conceptacle (Fig. Sargassum female conceptacle - Conceptacle bearing antheridia are called male conceptacles. 10. 3.118A). 1. 3.119C). When the oogonium comes out of the female conceptacle, through the ostiole, it at first remains attached to its apex by the mucilaginous thread, but afterwards set free and floats on the surface of sea-water. - Oogonium is single celled structure, which is sessile and remains embedded in female conceptacle. variations occur in other members of fucales conceptacles bisexual: fuci-js conceptacles unisexual: sargassum turbinaria antheridia : each with 64 antherozoids oogonia with 8 eggs > fuci-js 4 eggs > ascophyllum 2 eggs > pelvetia 1 egg > sargassum, ensures its survival under all eco-physiological conditions. Life Cycle of Sargassum (With Diagram) | Phaeophyta, Anatomy of Sargassum (With Diagram) | Algae, Diatoms: Characteristics, Occurrence and Reproduction. 3.121A). female conceptacle devt. Botany, Practical of Algae, B.Sc. It does not multiply asexually by means of spores. The basal cell, then undergoes repeated vertical divisions to form the basal fer­tile layer i.e., the inner layer of the conceptacle. x��Xˎd5��W�qޑ�H�D�Zb�X~۱�ܪ� 4��ҕ���籓?`�}B?5��������h�)1����|8=>��f�yz?�C|n-�d��!�֚����|��s�9Gl��\���;���Y��� GhY�٫��j�E�'l�6˯����7���ޘ~]hDž^����O���i��ɹ�- Z����ӗ�Z��>��J5���B� ۱7ߴ�3ё�ܵ�^%]E��_�z��5ㅪh�A�4��td��]��-�ź�[Z^��Vu���; �{��E|�������l����:'� }�E�G,@B��g�C^�~�-����t�S�/C��o��u%&�}�t~4��up��,'~�R6oki4���G�p6���,��_Ǫ��A��-�����׷� � +K� ࣸ���+����R �^惸m��]w���@��zϻG�(dgW�w ���$$���4�= The lower basal cells of the conceptacle are the antheridial initials forming papilla like outgrowths (Fig. Sargassum ilicifolium, S. tenerrium, S. wightii, S. duplicatum, S. myriocystum, S. christifolium, S. carpophyllum, S. cinereum and S. plagiophyllum. Just after fertilization the zygote undergoes germination (Fig. Sargassum shows diplontic life cycle without any alternation of generations (Fig. However, there may be overlapping generations in a single season occupying the same habitat. Fig. 3.122). Sargassum muticum. endstream ... Fucus female conceptacle. Asexual reproduction is absent. Internally it is almost alike with the axis but without medulla (Fig. Reproduction takes place by vegetative and sexual means. After liberation, the zygote gets attached with any solid substratum. The female egg liberates a volatile hydrocarbon, fucoserraten (a compound with 8 carbon atoms) which attracts the male antherozoids; these cluster around the egg and spin it; one penetrates the complex series of coats around the egg and karyogamy (nuclear fusion) occurs. The main axis is generally of 10 to 50 cm in length. Instead it reproduce by vegetative method and the formation of sex organs. There are a range of different conceptacles, classified according to the nature of the spores that they contain; some species may possess as many as four distinct types. The zygotic cell settles down and germinates to form a new diploid thallus. The cortex is situated next to meristoderm and occupies major part of the axis. The receptacle bears many fertile flask-shaped structures, the conceptacles. For example, Lithophyllum incrustans bears asexual, male, female and cystocarpic (strictly, a type of female) conceptacles, discussed below. 11. Sargassum resource is heavily destroyed and scarce in Northern China be- ... appeared in mature female conceptacle. <>stream 2008, Xie et al. Sargassum muticum. After fusion zygote is formed. Both stem and leaves are differentiated into epidermis, cortex and medulla. 3.119B). 3. The oogonial cell becomes enlarged and forms a spherical structure. These are flask-shaped with many sterile unbranched filaments, the paraphyses developed from the base. Sargassum shows diplontic life cycle without any alternation of generations (Fig. The diploid nucleus of the antheridial initial undergoes meiosis followed by repeated mitotic divisions forming 32-64 haploid nuclei. 2. (With Methods)| Industrial Microbiology, How is Cheese Made Step by Step: Principles, Production and Process, Enzyme Production and Purification: Extraction & Separation Methods | Industrial Microbiology, Fermentation of Olives: Process, Control, Problems, Abnormalities and Developments, The best answers are voted up and rise to the top. 3.118B). The apical cell of the stalk remains sterile and behaves as paraphysis. What is a mushroom shaped gland? Sargassum paniculatum - 1, habit of portion of a fertile branch with young receptacles, leaves and vesicles; 2, detail of a portion of a fertile branch with female receptacles; 3, detail of a portion of a fertile branch with male receptacles; 4, details of vesicles; 5, leaves from different branch orders.S. Many antherozoids get attached with the egg by their anterior flagella and their posterior ones help in swimming (Fig. Thus the thallus shows division of labour along with differentiation of tissues. The separated region grows and finally develops into a new individual like the mother. The medulla i.e., the inner layer consists of narrow, thick walled elongated cells. The axils of leaves develop long much branched flattened or cylindrical structures called receptacles. 7. This process repeats sev­eral times and thus a branched structure is formed with lateral sporangia arranged alternately (Fig. Fertile cavities, the conceptacles, containing the reproductive cells are immersed in the receptacles near the ends of the branches. In India it is found in Porbandar, Bombay, Okha, Lakshadweep Island etc. The top of an ostiole was smaller than other parts with a size between The wall of the oogonium consists of three layers, the outer exochite, the middle mesochite and inner endochite (Fig. The mature female conceptacle of Sargassum horneri (Turner) C. Agardh has an ostiole filled with a gelatinous plug. Light micrograph to show that the mucilage plug has the same consistency as the mucilage on the epidermis of the conceptacle (O = oogonium). 6. It is erect, flattened or cylindrical structure. The mature female and male receptacles of S. thunbergii were dumpy and acerose, respectively (Figure 2). Conceptacles were distributed in each receptacle. During development (Fig. 3.119F) is oval and covered by two walls, outer firm exochite and inner gelatinous endochite. %PDF-1.4 13. Share Your PDF File Outer to the cavity, cortex is present; which consists of a few layers and thinner cells than axis and finally it ends with a single layered outer meristoderm. In the genus Sargassum several species are dioecious; others are monoecious. Sargassum vulgare C. Agardh shows androgynous receptacles, each bearing on an average 12 unisexual conceptacles which open outside by ostiole, and wherein gametangia (antheridia or oogonia) lie interspersed with paraphyses. Find sargassum stock images in HD and millions of other royalty-free stock photos, illustrations and vectors in the Shutterstock collection. Sargassum horneri is an annual species, completing its entire life cycle (fig. Fertilisation takes place when the eggs remain outside but still attached with the con­ceptacle by gelatinous stalks (Fig. What is its function? The thallus is differentiated into a basal holdfast and an expanded, leafy, cylindrical main axis. Fucus male conceptacle. The plant body is diploid (2n), erect and branched thallus (Fig. In transverse sections of receptacles of S. kjellmanianum, male and female organs were found in distinct conceptacles of the same receptacle (Fig. The sterile conceptacles are also called cryptoblast or cryptostomata. The cells contain chromatophores and perform photosynthesis. Features 6. with attached to conceptacle mst- Oogonia attached to the conceptacle wall long gelatinous stalks; ov-ovum; ow-oogonial wall. The fertile and sterile conceptacle are almost similar. The conceptales with antheridia or oogonia are called male or female conceptacles. Vegetative reproduction : FRagmentation is the only known method of reproduction in the free floating species of sargassum. 3.Sketch label and describe female conceptacle of Sargassum. Department of Botany, DAV College, Jalandhar (PB.) TOS4. Due to its unlimited growth, the primary laterals are also called long shoots. Some of the basal cells of the inner layer of conceptacle instead of forming oogonia remain sterile and form sterile, long, hair-like struc­tures, the paraphyses (Fig. The air bladders help to float them in water (Fig. The oogonium in the conceptacle has cell walls that can be differentiated into a dense outer and a less dense inner microfibrillar layer. On both surfaces of the leaf there are many sterile conceptacles, the cryptostomata or cryptoblasts (Fig. The cells are meristema- tic in nature. ensures its survival under all eco-physiological conditions. <>stream These dark celled structures, after being given off from the conceptacle wall, appeat to curve upwards towards the ostiole. The uninucleate bodies metamorphose into pyriform, haploid biflagellate antherozoids (Fig. The conceptacle initial becomes flask- shaped. It takes place by fragmentation. The male and female receptacles had indistinguishable shape in some cases; thus, an immature thallus is impossible to be identified. Privacy Policy3. of . Content Guidelines 2. The main axis and primary laterals (long shoots) bear flat’ expanded structures, called secondary laterals or leaves. The lower one remains as concep­tacle Wall, whereas the upper one (Fig. 3.119C). Sargassum species are mostly monoecious. 303_1.tifAdministrator H��@au��HhE��� b�Eh/ѻ�S9�d3e��e��Y������X�yⅿH%�Ɂ�b�Q��D�ʡH�jW,����4dѡOf�,rm�@�v��*��6�_X���ݸp��$�fDʍ!/". For male it is called as Antheridia whereas in female it is called Oogonium. WM Batrachospermum fruiting WM In sterile concep­tacle it only develops sterile hairs, the paraphyses, but in fertile conceptacle it develops either antheridia or oogonia and also paraphyses in some regions. It consists of compactly arranged parenchyma cells of poly­gonal shape, rarely with intercellular spaces. The nuclei then accumulate some cytoplasm and form many uninucleate bodies. Interspaced between the oogonia are large elongate-celled branched paraphyses or sterile hairs. Sargassum horneri is one of the most important seaweeds used to restore degraded coastal environments near Nanji Island, China. It is very common in Africa, South America, Australia etc. The medulla is round and present in the middle region. These dots are the ostioles i.e., openings of the sterile conceptactes. 3.120F). 3.119D, E). 3.120D) which remains in the centres. Each one divides by a transverse wall into two cells. Receptacles in racemose branchlets (female receptacles are triquetrous, male receptacles cylindrical, subclavate, two-edged, dentate at margins) develop in axils of phylloids. Out of these, 7 nuclei degenerate and the remaining one functions as an egg (Fig. After meiosis oogonia and antheridia, the female and male reproductive organs, produce egg cells and sperm respectively that are … The paraphyses protrude out through the opening present on the outer side, the ostiole. This website includes study notes, research papers, essays, articles and other allied information submitted by visitors like YOU. 3.121D-H), while the oogoni­um still remains attached with the conceptacle. S. fulvellum is dioecious, and s. kjellmanianum is monoecious. 3.117D). Reproduction 7. The conceptacles bear sex organs. H��Wdc8M��O�뜇�����5/�*�; Sargassum. 3.120A). Taxonomic notes: Sargassum paradoxum is probably the largest species of Sargassum in southern Australia, being characterised by the large, undulate, spinous, lower laterals and the long, robust, receptacles. What are the general characters of bryophytes? This layer can store food material. 3.120C), then mitotic divisions and 8 nuclei are formed. However, its reproductive characteristics, especially those of oogenesis and the concomitant changes in photosynthetic activities, remained uncertain. The holdfast is discoid and serves the func­tion of anchorage with the substratum. Oogonium of Sargassum Sp. 3.117B). 3.121 B), but later they fuse together and form the zygote (Fig. But no matter how much money is forked out, the sargassum keeps coming. I. Scanning micrograph of female conceptacle, arrow indicates the ostiole mucilage plug (O = oogonium). 2a-e) in less than a year. The plant body of Sagassum is a diploid sporophyte. ensures its survival under all eco- Explain genic balance mechanism of sex determination. The difference lies in the activity of basal cells of the linear wall of conceptacle. The surrounding cells of the conceptacle initial divide rapidly and push it towards the inner side of the receptacle. After coming out, the wall of sporangium gets gelatinised and the antherozoids are liberated. Chapter: 6 Economic Importance of Algae 2 Marks Questions: 1. The zygote is diploid (2n) and on germination it develops sporophytic (2n) plant of Sargassum. Fucus monoecious conceptacle. Oogonium produces one egg and the anthe­ridium produces 64 biflagellate sperms. - At maturity, it is discharged through ostiole. The genus Sargassum (Spanish sargazo, sea­weed) is represented by about 150 species, out of which 1 6 species are found in India. Early stages of conceptacle development have been described in C. elongatum and C. maschalocarpum by Delf and in C. flexuosum by Dawson and my observations show a similar sequence of divisions in C. plumosum (Text-figs. Sargassum muticum. Fig. This cell is larger in size with dense protoplasm than the other surrounding cells. The reproductive organs are developed from this inner layer. It is flat and differentiated into outer meristoderm, middle cortex and inner medulla like the axis (Fig. dark pink ceramic glaze. In West Africa, a part of Atlantic Ocean becomes densely occupied by Sargassum and the region is called as ‘Sargasso sea’. The sex organs develop in separate flask-shaped bodies the conceptacles, developed on branched receptacles. iText 4.2.0 by 1T3XT The main axis bears many primary laterals arranged spi­rally in a phyllotaxy of 2/5. • Development of conceptacles. Scale = 100 ltm. Sargassum filipendula, a free-floating large kelp found in the Sargasso Sea, was discovered by Columbus in 1492, as the ships were held fast by the sea weeds. 3.117C). The tongue cell elongates and gradu­ally disappears. The stalk cell again undergoes transverse division and forms upper antheridial cell and lower stalk cell. The antherozoids and eggs i.e., the gametes, represent only the haploid (n) stage. Thus it shows a typical example of diplontic life cycle. Fucus female conceptacle VS Padina thallus WM Sargassum thallus (leaf) TS Sargassum male conceptacle TS Sargassum female conceptacle TS Sargassum bladder TS Laminaria Thallus TS Laminaria Receptacle VS Rhodophyceae (Red Algae) Amphiora WM Batrachospermum Veg. In all four species only a few, relatively large oogonia develop in each conceptacle. 3.119D). Development of oogonia of Sargassum horneri (Fucales, Heterokontophyta) and concomitant variations in PSII photosynthetic activities XIUJUN XIE 1,GUANGCE WANG 2*, GUANGHUA PAN 1,JIANZHANG SUN 3 AND JIAN LI 4 1Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457, China The lower cell develops into rhizoid and the upper cell undergoes repeated periclinal and anticlinal divisions, thus forming a thalloid sporophyte (2n) of Sargassum. The central region is occupied by a large hollow cavity filled with air and gases. 3.119H). Zygote germinates directly and produces a new sporophytic (2n) plant. 1 0 obj Name the types of nitrogenous bases present in the RNA. Internal Structure 4. 3.118) single superficial cell on the receptacular branch becomes enlarged and functions as conceptacle initial (Fig. After some time it comes out of the gelatinous wall. Diatomaceous earth is obtained from ----- a) Diatom b) Sargassum c) Ulothrix d) Spirogyra 2. Features 5. Sargassum muticum. 3.119A) again divides transversely and forms a lower stalk cell and an upper antheridial cell (Fig. I The meristoderm is made up of single layer of closely packed cells. 12. This layer possibly helps in conduction. Most of the species of Fucales reproduce sexually except Sargassum natans and Sargassum fluitans, which reproduce only by fragmentation (Lee, 2008).Reproduction is of oogamous type and reproductive structures in Fucales are borne in a special flask-like cavity, which is known as conceptacle. It is of oogamous type and takes place by the union of antherozoid and egg, developed in antheridia and oogonia respectively. 8. Since out-put of eggs is extremely low, 4 -6 per female conceptacle, Sargassum sp. Where are the pollen grains formed in the flower? In this article we will discuss about:- 1. of axis of Sargassum. Ist year, Paper-I, Sem. Development of conceptacle. Thus con­ceptacle contains oogonia intermingled with paraphyses. 3.120E). sargassum beds provide food, habitat, and nursery grounds for a wide array of marine organisms (Tsukidate 1992), while also providing food, alginates, feed, and bioactive compounds for people who harvest or culture sargassum (Belleme and Belleme 2007, Zhao et al. Types of conceptacle. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? 4 0 obj • Germination of Zygote. The sub-genus Sargassum ... 10-12 mm long and 1-2 mm in diameter, plants monoecious, male and female reproductive organs in separate conceptacles, but androgenous, with both sexes present in the same receptacles. The plant body is diploid except the antherozoids and eggs. The diploid (2n) nucleus undergoes first meiotic (Fig. The algae are free floating and brown in colour, commonly found in tropical seas, though some are found in Sargasso Sea (a region of North Atlantic Ocean). 2020-12-10T05:10:02-08:00 The mature oogonia come out of the conceptacle through the ostiole, but still they remain attached with the conceptacle base by a long gelatinous stalk formed by the exochite. 3.121C). Some of the cells of this layer function as an oogonial initials (Fig. Life Cycle Pattern. The leaves are flat, simple structures with distinct midrib and dentate, serrate or entire margins, with an acute apex. What is the significance of transpiration? ... (male and female gametangiain different conceptaclesbut in the same receptacle)].Receptacularbranchlets arisefrom the ... female conceptacle isclosed until egg liberation byapreviouslyunreported osti- The Conceptacles. 2. 3.119). Since out-put of eggs is extremely low, 4 - 6 per female conceptacle, Sargassum sp. Sometimes, the leaves growing towards sun­light show many dots on both the surfaces. Fertilization takes place in the usual way. At maturity the antheridium is detached from the stalk and comes out from the conceptacle through ostiole. On the main axis as well as on the primary laterals, the secondary laterals i.e., the leaves are replaced by many spherical, hollow bodies, called air bladders. 3.116). The released oogonium is “wrapped” in sulphated polysaccharide-rich wall layer known to provide protection against desiccation. This process repeats sev­eral times and thus a branched structure is formed with lateral sporangia alternately. Metamorphose into pyriform, haploid biflagellate antherozoids ( Fig and antheridia are in! The plant body is diploid except the antherozoids and eggs i.e., the cryptostomata or (. Except the antherozoids and eggs divisions to form a new individual like the outer side, cryptostomata. Or female conceptacles are also called cryptoblast or cryptostomata medulla i.e., the gametes, only! Without medulla ( Fig outside but still attached with any solid substratum oogonia develop in separate flask-shaped bodies conceptacles! Members like s. hystrix and 5. natans, multiply only by this method fertilization is,... Egg is not come out from the basal cell, the outer layer this layer function as egg. Online platform to help students to Share notes in Biology called cryptoblast or cryptostomata had indistinguishable shape in cases. Mst- oogonia attached to the conceptacle initial divide rapidly and push it towards the ostiole mucilage plug ( =... 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The sex organs develop in separate flask-shaped bodies the conceptacles, the growing. But without medulla ( Fig cylindrical main axis bears many fertile flask-shaped structures, the leaves differentiated. Gradually dege­nerate, Initially after fertilisation both the nuclei remain side by side ( Fig Botany DAV. Vegetative reproduction: FRagmentation is the only known method of reproduction in the conceptacle cell... Horneri ( Turner ) C. Agardh has an ostiole filled with air gases... Zygote undergoes germination ( Fig inner gelatinous endochite are also called cryptoblast cryptostomata. Shows diplontic life cycle without any alternation of generations ( Fig in some ;! Department of Botany, DAV College, Jalandhar ( PB. cell layers medulla. Is an annual species, completing its entire life cycle and growth Requirements | Industrial Microbiology how... An expanded, leafy, cylindrical main axis i.e., the leaves growing towards sun­light show many dots both! These dark celled structures, the ostiole mucilage plug ( O = oogonium.... Seaweeds used to restore degraded coastal environments near Nanji Island, China -6 per conceptacle. And primary laterals ), but later they fuse together and form the basal of..., haploid biflagellate antherozoids ( Fig into an antheridium ( Fig Island, China also... How much money is forked out, the cryptostomata or cryptoblasts ( Fig large hollow cavity filled with and! The function of anchorage with the con­ceptacle by gelatinous stalks ( Fig organs were found distinct..., subtropical and tropical regions of both Northern and southern hemispheres... appeared mature... ( female conceptacle of sargassum. Australia etc, arrow indicates the ostiole mucilage plug ( O = oogonium.... Egg and the concomitant changes in photosynthetic activities, remained uncertain 3.121d-h ), while oogoni­um., outer firm exochite and inner endochite ( Fig initial undergoes meiosis followed by repeated divisions!, then undergoes mitotic division and forms lower and upper large oogonial cell ( Fig nuclei and... Differentiated into a dense outer and a less dense inner microfibrillar layer the substratum is monoecious are! The sterile conceptactes sterile hairs n ) stage of both Northern and southern.... Takes place when the eggs remain outside but still attached female conceptacle of sargassum any solid.... Sessile and remains embedded in receptacles and s. kjellmanianum, male and female conceptacles are produced on separate male female... Many uninucleate bodies metamorphose into pyriform, haploid biflagellate antherozoids ( Fig the of... By visitors like YOU of three layers, the inner side of the gelatinous.! Undergoes mitotic division and by oblique septation it forms upper antheridial cell and an upper cell. Cell ( Fig with lateral sporangia arranged alternately ( Fig almost entirely filled by a transverse wall two... Lakshadweep Island etc the genus Sargassum several species are dioecious ; others are monoecious after fertilisation both surfaces. Horneri ( Turner ) C. Agardh has an ostiole filled with a gelatinous plug by. Typical example of diplontic life cycle divisions and 8 nuclei are formed Share Your Word File Share Your PDF Share! Solid substratum the function of anchorage, photosynthesis, storage, conduction and.! Called paraphyses ( Fig... appeared in mature female conceptacle abundant female conceptacles medulla,. Meristoderm ) Lithophyllum imitans, which is sessile and remains embedded in receptacles bodies conceptacles... Instead it reproduce by vegetative method and the region is occupied by a transverse wall two! Float them in water ( Fig remained uncertain region gets separated directly and produces a sporophytic!, its reproductive characteristics, especially those of oogenesis and the anthe­ridium produces 64 biflagellate sperms in conceptacle... Flat, simple structures with distinct midrib and dentate, serrate or entire margins, with an acute.! Arrow indicates the ostiole is Bread made Step by Step kjellmanianum is monoecious by vegetative and. 4 rounded oogonia middle region zygote gets attached with the egg by their anterior and... Male and female conceptacles are produced on separate male and female receptacles had indistinguishable shape in some cases ;,.

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