The leaves are flat, simple structures with distinct midrib and dentate, serrate or entire margins, with an acute apex. The lower basal cells of the conceptacle are the antheridial initials forming papilla like outgrowths (Fig. Sargassum shows diplontic life cycle without any alternation of generations (Fig. endstream :�h7b�.����jq �;(�GP"�i��8�m �d��(66d�q��Y� ͇divN�����#8S; ��ޡ��άÎ~�gF���P3&|��P�)�(˙ The nuclei then accumulate some cytoplasm and form many uninucleate bodies. Sargassum. Life Cycle Pattern. The oogonia (eggs) are released with a pheromone that triggers nearby male gametophytes to release the biflagellate antherozoids (sperm) for fertilization. Both stem and leaves are differentiated into epidermis, cortex and medulla. After fusion zygote is formed. It is of oogamous type and takes place by the union of antherozoid and egg, developed in antheridia and oogonia respectively. What is its function? Sketch, label and describe T.S. 3.120C). Vegetative reproduction : FRagmentation is the only known method of reproduction in the free floating species of sargassum. 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. Receptacles in racemose branchlets (female receptacles are triquetrous, male receptacles cylindrical, subclavate, two-edged, dentate at margins) develop in axils of phylloids. In the genus Sargassum several species are dioecious; others are monoecious. 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. Sargassum heterophyllum reproductive morphology. • Germination of Zygote. 13. 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 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. Thus it shows a typical example of diplontic life cycle. Disclaimer Copyright, Share Your Knowledge Diatomaceous earth is obtained from ----- a) Diatom b) Sargassum c) Ulothrix d) Spirogyra 2. Sargassum female conceptacle - Conceptacle bearing antheridia are called male conceptacles. 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. Share Your Word File 3.120F). Internal Structure 4. Fertile cavities, the conceptacles, containing the reproductive cells are immersed in the receptacles near the ends of the branches. In West Africa, a part of Atlantic Ocean becomes densely occupied by Sargassum and the region is called as ‘Sargasso sea’. 3.120A). The cells contain chromatophores and perform photosynthesis. <>stream Lamanaria 3 cell layers (medulla, cortex, meristoderm) Lithophyllum imitans. It bears long shoots of unlimited growth (primary laterals), leaves (secondary laterals), air bladders and receptacles. It reproduces by both vegetative and sexual means. 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 conceptacles bear sex organs. 4.Sketch label and describe female conceptacle of Sargassum. The spores develop into haploid male or female gametophytes, which eventually produce the sexual gametes. The axils of leaves develop long much branched flattened or cylindrical structures called receptacles. 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!/". Conceptacles were distributed in each receptacle. S. fulvellum is dioecious, and s. kjellmanianum is monoecious. Sargassum species are mostly monoecious. The mature antheridium (Fig. 3.120D) which remains in the centres. 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. TOS4. The latest sargassum map, published Thursday by the sargassum monitoring network. It is flat and differentiated into outer meristoderm, middle cortex and inner medulla like the axis (Fig. The zygote then divides transversely and forms lower and upper cell. Which organelle is known as “power house” of the cell? In this article we will discuss about:- 1. Name the types of nitrogenous bases present in the RNA. Sargassum contains higher amounts of protein essential These dark celled structures, after being given off from the conceptacle wall, appeat to curve upwards towards the ostiole. Yeast: Origin, Reproduction, Life Cycle and Growth Requirements | Industrial Microbiology, How is Bread Made Step by Step? I The oogonial cell becomes enlarged and forms a spherical structure. 13. The conceptales with antheridia or oogonia are called male or female conceptacles. It consists of compactly arranged parenchyma cells of polygonal shape, rarely with intercellular spaces. Life Cycle of Sargassum (With Diagram) | Phaeophyta, Anatomy of Sargassum (With Diagram) | Algae, Diatoms: Characteristics, Occurrence and Reproduction. The medulla is round and present in the middle region. However, there may be overlapping generations in a single season occupying the same habitat. The antheridial cell develops into an antheridium (Fig. The lower cell develops into rhizoid and the upper cell undergoes repeated periclinal and anticlinal divisions, thus forming a thalloid sporophyte (2n) of Sargassum. These dots are the ostioles i.e., openings of the sterile conceptactes. The receptacle bears many fertile flask-shaped structures, the conceptacles. Thus the thallus shows division of labour along with differentiation of tissues. �@�G�@��0�w��]��d:�� ���Z'䃴�M����ѱ��/���x������iWY+\�j���S�C�ӆ>��x�;���?��w�YZ�`���*��. Instead it reproduce by vegetative method and the formation of sex organs. Development of conceptacle. 3.116). It does not multiply asexually by means of spores. The sex organs develop in separate flask-shaped bodies the conceptacles, developed on branched receptacles. Interspaced between the oogonia are large elongate-celled branched paraphyses or sterile hairs. After liberation, the zygote gets attached with any solid substratum. 3.117A). It takes place by fragmentation. The antheridia are developed from the inner fertile layer of the antheridial conceptacle (Fig. 2. Scytosiphon sp. The genus Sargassum (Spanish sargazo, seaweed) is represented by about 150 species, out of which 1 6 species are found in India. of axis of Sargassum. Sargassum muticum. 1 0 obj The cells of the wall have many chromatophores. The thallus is differentiated into a basal holdfast and an expanded, leafy, cylindrical main axis. Sargassum horneri is an annual species, completing its entire life cycle (fig. The plant body of Sagassum is a diploid sporophyte. Oogonium of Sargassum Sp. Fucus monoecious conceptacle. 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. Sargassum muticum. 2020-12-10T05:10:02-08:00 4. 3.121D-H), while the oogonium still remains attached with the conceptacle. Just after fertilization the zygote undergoes germination (Fig. Fertilization takes place in the usual way. 6. 3.Sketch label and describe female conceptacle of Sargassum. The cells are smaller in size than meristoderm. Welcome to BiologyDiscussion! 3.119C). The sterile conceptacles are also called cryptoblast or cryptostomata. At maturity the antheridium is detached from the stalk and comes out from the conceptacle through ostiole. The reproductive organs are developed from this inner layer. 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