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Describe Fungi. Discuss structure of thallus, nutrition and reproduction in them

Fungi are thallophytes of chlorophyll less non vascular plants that live parasitically or saprophytically and reproduce by spores. Branch of botany which deals with fungi is called Mycology. Study of disease caused by fungi are called plant pathology. Fungi are found every where. They have no chlorophyll and may be saprophytes, parasites or symbionts. Some fungi are aquatic. Some are terrestrial. They occur in soil. Some live in tissues of plants and animals. Fungi can grow on our food stuffs like bread, jams, pickles and fruits. They are also present all the time in air. Vegetative structure of Fungi: Fungi consists of network of branched filaments called hyphae. Entangled mass of hyphae is myceliym. Hyphae may be segmented or non segmented. Some fungi like yeasts (Saccharomyces) and Syachtrium lack mycelium. Cell wall of mycelium is made up of chitin or fungal cellulose along other substances. Chief food reserves are glycogen and oils. Fungal cells contain cytoplasm, nuclei and vac

Merits and Demerits of Fungi | economic importance of Fungi

Fungi include many species which are of economic importance to man our lives are linked with Fungi. We are harmed and benefited by Fungi directly or indirectly. Some account for the beneficial and harmful activities of Fungi is as under: Some useful activities of fungi are: Destruction of organic waste: Saprophytic Fungi decompose plant and animal remains by acting as natural scavengers. Carbon dioxide released in the process is used by green plants. By some workers, saprophytic Fungi have been designated as vegetative vultures. In the Industry Many fungi are used in the commercial preparation of many organic acids and some vitamin preparations. Aspergillus miger, A. Glaucus, A. clavatus, and citronyces citricus have been recommended for the preparation of citric acid. Many fungi also prepare gluconic acid lactic acid. Aspergillus and Fusarium are sources of riboflavin, a constituent of vitamin B. Yeasts are also rich in vitamin B. Recently Fungi have been f

Economic importance of Algae

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Many algae are used by human beings for food, manufacture iodine in some other purposes from ancient times. Many researches are being done in phycology (study of algae) and many workers are trying to find out the food value of algae, their importance in industries and importance in agriculture. The importance of role played by algae in the world is be coming more appreciated each day because of the increased utilization that many of them are valuable to man. Value is as under. (1) Algae as food: Large numbers of Algae are used as source of food by human beings. They are rich in carbohydrates, inorganic substances and vitamins. Vitamins A C D and E are main constituents of these plants. Parphyratenesa is very popular and eaten throughout Japan . Kambu is another product of algae. Laminarta is used in Japan as standard food. Spirogyra is chief source of food ulva (sea lettuce) is also used be man as food. Recently green algae chlorena has drawn attention of psychologists. Percentage

Modes of perennation in fresh water and subarial algae

Perennation includes methods employed by plant to pass through unfavorable period for vegetative growth. In perennation period normally all the activities of organism cases and to pass through these unfavorable periods the living organism develops some stage in life cycle which is protected by thick persistent wall. Marine algae live in conditions where variations in external conditions of life are rare. The freshwater and sub aerial algae are however exposed to the dangers of desiccation and extremes of temperature. They develop certain devices which enable them to carry through the period of sever conditions into the next growing season. Protective devices constitute the means of permeation. Main methods of perennation Fresh water and sub aerial algae are: Akinetes : These are formed during conditions of draught e.g. In ulothric, cladophora, pithophora, oosgonium and nostor. Akinetes are produced ogengly in each cell by rounding off cytoplasmic contents of the cell. The thick

Origin and Evolution of sex in Algae

Sexual reproduction is characterised by the fusion of two similar or dissimilar cells. This is a sign of relatively advanced stage in evolution. Sex is not an obvious in the lower plants (like algae) as it is in higher plants. But in any way the study of reproductive processes of various classes of Algae throws considerable light on the origin and evolution of sex in the branch of plants like Algae. Origin of Sex: Most primitive algae the cyanophyceae (Myxophyceae) reproduce only the method of asexual and vegetative reproduction. Sexual reproduction is entirely absent in their case. In forms like Nostoc and oscillatoria, it takes place by means of hormogones in which the plant body breaks up into group of few cells. In class xanthophyceae, chrysophyceae, cryptophyceae and dinopphyceae, sexuality is rare and has not much evolved beyond the stage of isogamy. In higher classes of algae reproduction takes place by vegetative, asexual and sexual methods. The commonest method of asexual re

Give an account of structure, reproduction and life history of Batrachospermum

It is fresh water red algae and belongs to class Rhodophyceae and normally lives in cool, well aerated clear and shady situations. Plant body is filamentous freely branched and gelatinous in texture. Plant is like a chain of delicate beads. Each bead consists of a whorl of densely branched laterals of limited growth. Main axis consists of single row of elongated cells placed one above the other. From main axis arise branches of unlimited growth. Also node cells give rise to filaments which grow downwards the next node covering the axis cells forming pseudo cortex. Each cell of filament consists of two layered cell wall outer of pectin and inner of cellulose, cells are unimucleaet and contain a large number of parietal chromatophores, each with a single pyrenoid. Growth takes place by an apical cell. Reproduction: It takes place by sexual method. Sexual reproduction: It is advanced oogamous type. Plants may be monoecious and dioecious. Male reproductive organ is antheriduim and female

Give illustrated account of life history of Ectocarpus

It is marine Algae remains attached to substratum by rhizoids. Some species may be parasitic or may occur on higher members like of order fucales. Plant body is branched and has brown filaments which are slender. Plant body is made up of two parts, a creeping portion which serves as holdfast and a number of branches which arise from it. Filaments are made up of single row of cells. Each cell is uninucleate small and rectangular and has many chromatophores containing brown pigment. Pyrenoids are also present in chromatophores. Growth of filament is intercalary. Plant is autotrophic in nutrition. Reproduction: Ectocarpus reproduces by Asexual and Sexual method. Asexual Reproduction: (A) This takes place by biflagellate zoospores produced in unicellular sporangia which are borne by diploid asexual plant. They start as simple globular cells filled with Protoplasm. Nucleus undergoes single reduction division followed by simple division. Around each daughter nucleus protoplasm collects to f

Give general features and classification of Phaeophyceae

General features of class phaeophyceae: They are called brown algae, few live in freshwater and majority live in sea water. The body of plant varies from simple branched filaments to large leathery branched structures with highly differentiated thallus. Unicellular, colonial or un-branched filamentous forms are not found in this class. There is interval differentiation of thallus into epidermis, cortex and medulla. The cell has usually two layered cell wall, primordial utricle, a nucleus and chromatophorus without pyrenoids. Plants are brown in coloure due to presence of fucoxanthin in addition to chlorophyll. There are also present highly retractive colourless fucosan vesicles. Food reserve is found in the form of soluble complex carbohydrate like laminarin, mannitol and fat instead of starch. Reproduction takes place by vegetative, asexual or sexual methods. Vegetative reproduction takes place by frognuentation. Asexual reproduction takes place by pear-shaped zoospores or naked aplan

Describe briefly structure and life cycle of chara

Chara is aquatic attached to muddly or sandy bottom of the pools, lakes and slow flowing streams. Few species are marine. Plant body consists of an erect branched axis which may grow to 20-30 can. The axis has district nodes and internodes. From each node arise a whorl of laterals of limited growth called leaves. From the axis of some leaves branches of unlimited growth may arise. Each branch bears nodes and internodes. Plant is attached to substratum by colourless branched multi-cellular rhizoids which arise from lower nodes of axis. Growth of axis in length takes place by means of single dome shaped apical cells. Each node has a plate of cells while inter-node consists of single elongated cells. Each cell has a cell wall made up of cellulose and deposit calcium carbonate. They contain a single nucleus, dense cytoplasm with many discoid chloroplasts. Reproduction: In chara it takes place by vegetative and sexual method. 1. Vegetative reproduction: It takes place as under: (i)      

Describe structure and Reproduction in Nostoc

It is blue green alga of filamentous form. Nostoc is present in ponds, ditches and other pools and also in soil. Few species lie in intercellular cavities of plants like duck weed and root of cycas and are called endophytic. Some lead symbiotic life with a fungus forming a lichen. Each jelly like mass of Nostoc consists of many slender long and short inter woven filaments which look like chain of beads. Each filament is un-branched and consists of a row of rounded or oval cells like series of beads in a chain. There is often a gelatinous sheath convering each filament in which entangled masses of Nostoc filaments remain embedded. Each cell is differentiated into two regions called chromplasm and an inner colourless region called central body (as in oscillatoria). The filament increases in length by cell division in one plane only. Some enlarged vegetative cells with thickened walls and transparent contents are seen to occur at frequent intervals and also at the ends are called hetero

Structure and reproduction of Oscillatoria

It is a dark blue green filamentous alga. It floats in ditches and shallow pools of water and on wet rocks and walls. Filaments of oscillatoria are entangled in masses which float on water. Each filament is slender, un-branched and cylindrical, consisting of a row of short cells. The individual cells are the oscialltoria plants and the filament is regarded as a colony. All the cells of the filament are alike except end cell which is usually convex and there is no differentiation into the base and the apex. Some empty cells occur in some of the filaments. The protoplast of each cell is differentiated into two regions: a coloured peripheral zone the chromoplasm and an inner colourless zone the central body. Colour is due to the presence of chlorophyll and phycocyanin (a blue pigment), which diffuse through the chronmoplasm. There is no plastid. True nucleus is also absent. The central body however is regarded as an incipient nucleus with only some chromatin but without nuclear membrane

Structure and Reproduction in Spirogyra

It is a green free floating filamentous alga present in ponds, ditches and springs. Each spirogyra filament is un-branched and consists of single row of cylindrical cells. The walls are made up of cellulose and pectin. Pectin swells in water into a gelatinous sheath. Filament shows no difference in base and apex. Each cell has a lining layer of protoplasm, one or more spiral bands of chloroplasts with smooth, wavy or serrated margins and a distinct nucleus situated in the middle. The spiral chloroplasts are the characteristic feature of spirogyra. Each chloroplast has a number of nodular proplasmic bodies called pyrenoids around which minute starch grains are deposited. If the filament happens to break up into pieces, they grow up into new filaments by cell division. Reproduction: It takes place by sexual method. It consists of fusion of two similar gametes i.e. isogametes and the process is called conjugation which takes place between the cells of two filaments. Sometimes conjugation

Tthe structure and reproduction in ulothrix

Body of ulothrix has un-branched filaments. Filaments contain short cylindrical cells joined end to end. Cells are as broad as long. The filament remains attached to substratum by modified based cell called hold fast. Upper cell or tip cell is sub spherical in outline. Each cell except hold fast cell has got an outer wall composed of cellulose plus pectic substances. Within the cell wall is cytoplasmic layer in which nucleus is embedded. Chloroplast has two more pyrenods. Filament is autotrophic in nutrition and grows in length. Reproduction: It takes place by vegetation, Asexual and Sexual method. (1) Vegetative Reproduction: It takes place by chance but not by regular method of multiplication. In this case the filament breaks up into two or more parts and each part is capable of converting itself into a new filament. (2) Asexual Reproduction: (A) By zoospore formation: The cell of filament under favourable conditions produces the zoospores. The zoospores are produced by ordinary

Structure and Life Cycle of Chlamydomonas

It is unicellular green algae found in the standing water of ponds, pools, and ditches. Each cell is biflagellate spherical in shape. The cell wall is thin anterior end of the Chlamydomonas is papillate. At the anterior end at the right angles of the flagella are two contractile vacuoles. They help in the excretion and respiration of the plant. Towards this end on one lateral side is an eye spot or stigma which is reddish or brownish-red in color due to a pigment harmatochrone. This eye spot is sensitive to light. Each cell has a basin-shaped or cup-shaped chloroplast on posterior regions. There is a single pyrenoid towards the base of the chloroplast. Starch is formed around the pyrenoid. The nucleus lies in the center of the cell. In nutrition cells of chlamydomonas are autotrophic due to the presence of chloroplasts water and inorganic salts are absorbed over the whole surface of the cell. REPRODUCTION: It takes place either by the asexual or sexual method. (1) Asexual repr

Structure of Thallus in Chlorophyceae

Plants of chloroplyceae show variations in vegetative structure from unicellular to multicellular forms. They are as under (1) Motile Form :- In the organization of thallus these forms of algae are simplest. They are unicellular and remain motile. e.g. ehlamydomonas in green algae. This is spherical, unicellular, unimucleate and biflagellate structure with cup-shaped chloroplast. The cells swim with the help of flagella. Motile unicellular algae from celonies which move about in the water with the help of flagella of peripheral cells. Each colony has a definite number of cells arranged in a specific manner e.g. volvox (2) Palmelloid forms:- Palmella stage is a temporary phase in life history of many algae e.g. chlamydomonas but in certain member of chlorophyceae xanthophyceae, chrysophyceae, this state of existence becomes permanent. Plant body remains embedded in a common gelatinous matrix of reproduction e.g.: sphaerocystis. FIG 1-C PAGE 16 ALGAE BY G.L. CHOPRA (3) Cocoid fo

Life cycle of Vaucheria

What is Vaucheria? Vaucheria is green freshwater alga found in ponds, ditches and wet soil. It is not free floating like spirogyra but is mostly attached to substratum by colourless rhizoids or holdfasts. It is thallus is single branched tubular filament. It contain many minute nuclei present in living layer of cytoplasm surrounding a large central vacuole. Such structure is called coenocyte. Septa appear in connection with reproductive organs. Asexual reproduction in Vaucheria It takes place by large solitary zoospore. During its development the apex of filament swells up, becomes club shaped and is separated from rest of filament by a septum. This club shaped body is called zoosporangium. Its protoplasmic contents become rounded off forming a single zoospore wall of zoosporangium, ruptures at the apex, and the zoospore escapes by terminal pore and begins to rotate. Zoospore is an oval body of large size. Central part of it is occupied by large vacuole and in surroundings zone

Illustrated account of life history of Volvox

It is fresh water colony forming free-swimming green alga found ponds and other pools of water during and after rains. Volovox has reached highest degree of colony formation. Each colony or coenobium consists of a few hundreds to several thousands cells arranged in peripheral layer to form a hollow sphere containing water or a dilute solution of gelatinous material. Each cell of colony has gelatinous sheath and cells are held together in a colony by sheaths secreted by individual cells. Cells are connected by delicate strands of cytoplasm. Individual colony freely swims about in water. Each volvox cell is like chlamydomonas. Each mature colony has two kinds of cells: numerous small vegetative cells and few large cells among them. Vegetative cell has two cilia protruding outwards and vibrating 2 to 5 contractile vacuoles, a central nucleus a cup shaped or plate like chloroplast with one pyrenoid and one eye spot. Vegetative cells do not divide. Large cells of colony are Reproductive c

Describe methods of reproduction in ordogonuim

Algae are mostly unicellular. Algae bear mostly chlorophyll and they are autotrophic thalloid plants. They are present in a variety of habitats but majority of them are aquatic. Plant body does not show differentiation into various tissue systems. Reproduction is vegetative and asexual and sometimes sexual. REPRODUCTION IN ORDOGONUIM: It takes place by three methods i.e. vegetative, asexual and sexual. 1. Vegetative reproduction in ordogonium: It is simple type of reproduction in which the filament of ordogonuim breaks up into many small portions, each of which divides into new filaments. 2. Asexual reproduction in ordogonuim: (i) By Zoospore: All cells of the filaments are capable of forming zoospore except basal and apical cells. Cytoplasm of zoospore forming cell Zoosporangium contacts and a hyaline receptive spot is formed. Ring appears around the margin of hyaline area. Each zoosporangium forms a single zoospore liberated by transverse split near the apex of zoosporangium.

Distinguish between Algae and Fungi. Mention economic importance of Algae and Fungi.

Algae 1. Algae are green Thallophytes bearing green colouring matter chlorophyll. 2. Algae are autotrophic plants i.e. they manuface their own food with the help of chlorophyll. 3. Body of Algae is formed of true Parenchymatous tissue. 4. Cell wall is formed of true cellulose. 5. Algae live in water or wet substrata. 6. Reserve Carbohydrate in Algae is starch. Fungi 1. Fungi are non green Thallophytes with no chlorophyll. 2. Fungi are heterotophic. They get food from decaying animal or vegetative matter or from tissue of living plants of animals.  3. In fungi body is formed of false tissue or bsendoparenchyma formed of threads called hyphae.  4. Cell wall is formed of Fungus cellulose or Chitin mixed with cellulose.  5. Fungi live as parasites on other plants or animals or saprophytes on decaying animals.  6. Reserve Carbohydrate in Fungi is Glycogen. In structure they both are unicellular, multi-cellular, filamentous and reproduction or thyloid is then may

What is Cyanophyta? Describe cell structure and economic importance of cyanophyta

Cyanophyta is division of Algae which includes class cyanophyceae or myxophyceae and the plants included in it are called blue green Algae because their pigment is bluish green. C-Phycocyanin. They are containing chlorophyll. They bear no well organised cell organelles. Pigments are present in chromoplasm. Nucleus is primitive type and takes nuclear membrane and nucleolus. They bear no flagella and they can move by gliding action. They are unicellular colonial in form cells are present in common gelatinous matrix. Filaments are unbranched and uniseriate or may sometimes show preudobranching. Their structure is prokaryotic. Cell wall is formed of micro fibrils held together in mucilage sheath. Orientation of fibres may vary in different species and may be reticulate as Nostoc. Cell wall is differentiated into four layers. It is formed of mucopeptides, Carbohydrates, amino acids and fatly acids. Pain pigments are chlorophyll a, c Phycocyanin and c Phycocrythrin and they give blue green

What is Algae? Give various kinds of Reproduction in Algae

Algae are small microscopic plants and are mostly aquatic. Chlorophyll and other pigments are present in the body. Algae can manufacture food by normal process of photosynthesis and are called autotrophic. Cell wall is made up of cellulose. Starch is reserve food material. They grow in habitat where light is present. Usually asexual reproduction takes place and rarely sexual, also vegetative. Vegetative Reproduction: In this process portions of plant body are separated to give rise to new individuals without any change in the protoplast. Under favourable conditions it takes place by fragmentation in which whole plant body breaks up into small units which grow independently. In mynophyceae it takes place by hormogones formation. E.g. Plenrococcus. Asexual Reproduction: It takes place by:  (1) By Zoospores: Zoospores are formed division of contents of parent cell. In filamentous forms like ulothrix zoospores are formed from older cells of the filament. Cytoplasm is divided to form zoo

Describe Pigmentation and classification of Algae

There are three kinds of Pigments in Algae.  (1) Chlorophyll: It is green colouring matter and is photosynthetic pigment. Chlorophyll is not present in cyanochlorapta. Pigments in algal cells are contained in plastids or chromatophores which vary in shape in different groups. When plastic is rich in chlorophyll it is called chloroplast.  (2) Carotenoid: They are unsaturated hydrocarbons and are of two types (i) Carotenes and (ii) Xanthophylls. About five different carotenes are found in algal cells. There is large number of xanthophylls in present in algal cells. Xanthophylls include Peridin, Myxoxanthin, Tetraxanthin, Anthraxanthin and Fucoxanthin.  (3) Biloprotein: They are water soluble and are present in Cryptophyta, Cyanochloranta and Rhodophyta and are of two types called phycocyanin and phycoerythrin. Classification: Important cases of Algae are: Class (1) Chlorophycrae (green algae): Pigments are present in plastids or chromatophores. Pigments are chlorophyll, xanthophyl