JULY-DEC_2022_BSCBT_1_SEM_V9_BSCBT103_BSCBT103BZBC102___Unit_3_PPT.pptx

JULY-DEC_2022_BSCBT_1_SEM_V9_BSCBT103_BSCBT103BZBC102___Unit_3_PPT.pptx
BSc BT/ZBC Semester-I Plant Diversity BSCBT103BZBC102 Dr. Niharika Dewangan Assistant Professor Department of Botany Kalinga University Naya Raipur (C.G.) PLEASE LEAVE THIS SPACE BLANK
COURSE OBJECTIVES • The course aims at making the students understand the diversity among algae, fungi, bryophytes ,pteridophytes and Gymnosperms. • To impart an insight into the modern classifications in lower forms of plants. • To impart basic knowledge of plant diversity. • To train the students to pursue further education. BSCBT103/BZBC102-Plant Diversity 2
COURSE OUTCOMES • On completion of the course, students are able to: • Understand the diversity among Algae, Fungi, Bryophytes, Pteridophytes and Gymnosperms. • Understand the life cycle pattern of plant diversity. • Know the Economic Importance of plant diversity BSCBT103/BZBC102-Plant Diversity 3
CONTENTS • Bryophyta: General characteristics • Bryophyta: Classification • Bryophyta: Economic Importance • Life Cycle of Marchantia • Life Cycle of Anthoceros • Life Cycle of Funaria BSCBT103/BZBC102-Plant Diversity 4
REFERENCES/TEXT BOOKS • Introduction to Botany – Bendre & Kumar • Botany for degree students – Algae: Vashishtha et al. • Botany for degree students – Bryophyta: Vashishtha et al. • An introduction to Pteridophyta – A Rashid • Botany for degree students: B.P.Pandey • Botany: S.B. Agrawal BSCBT103/BZBC102-Plant Diversity 5
LECTURE PLAN Lecture No. Topics to be covered Slide No. L-1 Bryophyta: General characteristics 8-11 L-2 Bryophyta: Classification 12-17 L-3 Bryophyta: Economic Importance 18-26 L-4 Life Cycle of Marchantia 27-53 L-5 Life Cycle of Anthoceros 54-76 L-6 Life Cycle of Funaria 77-101 Quiz 102-111 BSCBT103/BZBC102-Plant Diversity 6
UNIT III BSCBT103/BZBC102-Plant Diversity 7
BRYOPHYTA: GENERAL CHARACTERISTICS • The term Bryophyta originates from the word ‘Bryon’ meaning mosses and ‘phyton’ meaning plants. Bryophyta includes embryophytes like mosses, hornworts, and liverworts. • These are small plants that grow in shady and damp areas. They lack vascular tissues. They don’t produce flowers and seeds, instead, reproduce through spores. The study of bryophytes is called bryology. • Bryophytes are called “amphibians of the plant kingdom” because they are terrestrial plants, but require water to complete their life cycle at the time of sexual reproduction. BSCBT103/BZBC102-Plant Diversity 8
GENERAL CHARACTERISTICS OF BRYOPHYTES • Plants occur in damp and shaded areas • The plant body is thallus like, i.e. prostrate or erect • It is attached to the substratum by rhizoids, which are unicellular or multicellular • They lack true vegetative structure and have a root-like, stem-like and leaf- like structure • Plants lack the vascular system (xylem, phloem) • Bryophytes show alternation of generation between independent gametophyte with sex organs, which produces sperm and eggs and dependent sporophyte which contains spores • The dominant part of the plant body is gametophyte which is haploid • The thalloid gametophyte is differentiated into rhizoids, axis and leaves BSCBT103/BZBC102-Plant Diversity 9
GENERAL CHARACTERISTICS OF BRYOPHYTES • The gametophyte bears multicellular sex organs and is photosynthetic • The antheridium produces antherozoids, which are biflagellated • The shape of an archegonium is like a flask and produces one egg • The antherozoids fuse with egg to form a zygote • The zygote develops into a multicellular sporophyte • The sporophyte is semi-parasitic and dependent on the gametophyte for its nutrition • Cells of sporophyte undergo meiosis to form haploid gametes which form a gametophyte • The juvenile gametophyte is known as protonema • The sporophyte is differentiated into foot, seta and capsule BSCBT103/BZBC102-Plant Diversity 10
BSCBT103/BZBC102-Plant Diversity 11 The life cycle of bryophytes
CLASSIFICATION OF BRYOPHYTES BSCBT103/BZBC102-Plant Diversity 12
CLASSIFICATION OF BRYOPHYTES • According to the latest classification, Bryophyta is divided into three classes: Hepaticopsida (Liverworts) Anthocerotopsida (Hornworts) Bryopsida (Mosses) • A. Hepaticopsida (Liverworts): The name hepaticopsida comes from the word “hepatic” meaning liver. Liverworts come under this class. • Hepaticopsida is further divided into 4 orders: Marchantiales (e.g. Riccia, Marchantia) Sphaerocarpales (e.g. Sphaerocarpos) Calobryales (e.g. Calobryum) Jungermanniales (e.g. Pellia) BSCBT103/BZBC102-Plant Diversity 13
HEPATICOPSIDA • The main characteristics of the class hepaticopsida are: • Gametophyte plant is either thalloid or foliose • In foliose forms, leaves are without midrib and dorsiventral • Thalloid is dorsiventral, lobed and dichotomously branched • Each cell of thallus contains many chloroplasts without pyrenoids • Rhizoids are unicellular, branched and aseptate • Sex organs are borne dorsally embedded in gametophytic tissues • The sporophyte is made up of only capsule (in Riccia) or foot, seta and capsule (in Marchantia) • The columella is absent in the capsule • Sporogenous tissues develop from endothecium BSCBT103/BZBC102-Plant Diversity 14
B. ANTHOCEROTOPSIDA (HORNWORTS): There are around 300 species present in this class. They are commonly known as hornworts. It has only one order i.e. Anthocerotales. Examples: Anthoceros, Megaceros, Notothylas The main features are: • The gametophytic body is flat, dorsiventral, simple thalloid without internal differentiation • Rhizoids are smooth-walled • Each cell has one chloroplast with a pyrenoid • Sex organs are present dorsally embedded in the thallus • The sporophyte is differentiated into foot, meristematic zone and capsule • Sporogenous tissues develop from amphithecium • Pseudoelaters are present in the capsule • The columella is present in the capsule, which originates from endothecium BSCBT103/BZBC102-Plant Diversity 15
C. BRYOPSIDA (MOSSES): It is the largest class of Bryophyta with around 1400 species. They are commonly called mosses. Examples: Funaria, Polytrichum, Sphagnum. • Bryopsida is further divided into 5 orders: Bryales Andreales Sphagnales Polytrichales Buxbaumiales BSCBT103/BZBC102-Plant Diversity 16
The main features are: • The gametophyte is differentiated into protonema and foliose gametophore • Foliose is made up of stem as an axis and leaves without midrib • Rhizoids are multicellular with oblique septa • Sex organs are borne apically on stem • Elaters are absent • The sporophyte is differentiated into foot, seta and capsule • Sporogenous tissues develop from endothecium • Columella is present • Dehiscence of the capsule takes place by separation of the lid BSCBT103/BZBC102-Plant Diversity 17
BRYOPHYTA: ECONOMIC IMPORTANCE BSCBT103/BZBC102-Plant Diversity 18
ECOLOGICAL IMPORTANCE OF BRYOPHYTES • Bryophytes have great ecological importance. Mosses and lichens are the first organisms to colonise rocks. • They decompose the rock making it suitable for the growth of higher plants. The acid secreted by lichens, death and decay of mosses helps in soil formation • Bryophytes grow densely so act as soil binders • Mosses play an important role in bog succession. Mosses can change the landscape from open soil to climax forest. The thick mat formed of mosses forms suitable substratum for germination of hydrophilic seeds due to the presence of water and humus. In the course of time, the dead and decayed mosses and hydrophilic plants form a solid soil for mesophytic development BSCBT103/BZBC102-Plant Diversity 19
ECOLOGICAL IMPORTANCE OF BRYOPHYTES • They prevent soil erosion by reducing the impact of the falling rain • They reduce the amount of run-off water due to their water holding capacity • They help in recycling of the nutrients • They act as a rock builder. Certain mosses (Bryum) along with algae, present in calcium bicarbonate rich shallow water or lakes form calcareous (lime) rock-like deposits around these plants. These plants decompose bicarbonate ions resulting in the precipitation of insoluble calcium carbonate. This mineral deposit continues to grow and extends over several hundred square feet area. BSCBT103/BZBC102-Plant Diversity 20
BRYOPHYTES AS FUEL • Liverworts and mosses have long been tried and used as a fuel in developed countries like Finland, Sweden, Ireland, West Ger-many, Poland and Soviet Union. • Peat a brown, soil-like material characteristic of boggy, acid ground, consisting of partly decomposed vegetable matter. • Peat is suitable for production of low and intermediate BTU gas as well as hydrogen, ethylene, natural gas, methanol and Fisher Tropsch gasoline .• Peat mosses are best suited for the production of methane, and peat is likely to become an important source of fuel for production of heat,methane, or electricity in the future. BSCBT103/BZBC102-Plant Diversity 21
HORTICULTURAL USES • There is a long tradition of use of bryophytes in horticulture as soil additives, because of their high water holding capacity and to air. Peat is an important soil conditioner and is commonly used for agricultural and horticultural purpose Bryophytes as ornamental plant• Bryophytes have also been used for green house crops, potted ornamental plants and seedlings, and in garden soil. s around the world. As preservative agent Bryophytes have excellent power to absorb moisture and can act as a goodpreservative agent . They not only help to prevent food but also help to preserve death bodies. BSCBT103/BZBC102-Plant Diversity 22
CONT…. • Moss industry • Moss industries in France manufacture moss carpets in various sizes. • They are easy to fix along the roads, lawns, play grounds, etc. • In Sri Lanka,a wide range of eco-friendly products such as coir pots, coir fiber pith (coco - peat), moss sticks, hanging wire baskets and basket liners are ma House Construction •These tiny plants are used in the construction of houses andtheir furnishings. •At Kapkot in the Himalayas, villagers use moss mats withshrubs, grasses, and bamboo to make a pharki, a kind of doorplaced at the openings of their temporary huts.Sphagnumpeat, peatcrete and peatwood are the newmaterial use for making houses ,they are low cost and easyto transport. de using bryophytes. BSCBT103/BZBC102-Plant Diversity 23
CONT…. • Household Uses •The Himalayans also use mosses as insect repellents when storing food. •Local mosses and liverworts are dried, made into a coarse powder that is sprinkled over grains and other goods to be stored in containers. • Fibre industries •Mosses are mixed with wool to make cheap clothes. •They are used in decoration of net bags and other objects. •Women also wear their steam like structure in their hair and as decorations in bracelets . •Used in hiking boats to absorb odour and moisture. •Used in lining of diapers to improve absorbing power. BSCBT103/BZBC102-Plant Diversity 24
CONT… • Medicinal Uses Sphagnol’chilblains, scabies, acne and other forms of skin diseasesUse for curing for allaying arising Skin Help to curefrom insect bites. treatment ringworms. Ash of moss is mixed with honey and fat to treat cuts, burns and wounds • Medicines cystitis cardio- vascular bronchitis system China in the business oftonsillitis medicines tympanitis made up of bryophytes • Use in Biotechnology• Transgenic Physcomitrella are now being used to produce ‘blood-clotting factor IX’, for the treatment of haemophilia’ B and other proteins BSCBT103/BZBC102-Plant Diversity 25
CONT… • Medicinal uses: • Sphagnum is used in surgical dressing due to its high absorptive power and some antiseptic property for filling absorptive bandages in place of cotton for the treatment of boils and discharging wounds • Marchantia has been used to cure pulmonary tuberculosis and affliction of liver • The decoction of dried sphagnum is used in the treatment of acute haemorrhage and eye infections • Peat-tar is antiseptic and used as a preservative. Sphagnol, which is a distillate of peat-tar is used to treat skin disease • Polytrichium species has shown to dissolve stone in kidney and gall bladder • Antibiotic substances can be extracted from certain bryophytes having antibiotic properties • In research: Mosses and liverworts are used in research in the field of genetics. The mechanism of sex determination in the plant is discovered in liverworts • Packing material: Dried mosses make an excellent packing material for fragile goods like glassware, bulbs. For trans-shipment of living material such as cuttings and seedlings as they have water retention capacity BSCBT103/BZBC102-Plant Diversity 26
BSCBT103/BZBC102-Plant Diversity 27 LIFE CYCLE OF MARCHANTIA
SYSTEMATIC POSITION • Division : Bryophyta • Class : Hepaticopsida • Order : Marchantiales • Family : Marchantiaceae • Genus : Marchantia BSCBT103/BZBC102-Plant Diversity 28
OCCURENCE • • The genus Marchantia includes about 65 species distributed all over the world. In India, only 11 species have been reported. • • All the species are terrestrial growing on moist shaddy places, damp soil, moist rocks and banks of streams. • • Common Indian species are : M. polymorpha, M. palmata, M. nepalensis, M. indica, M. simlana BSCBT103/BZBC102-Plant Diversity 29
BSCBT103/BZBC102-Plant Diversity 30 GAMETOPHYTIC GENERATION
VEGETATIVE STRUCTURE • Dorsal Surface • prominent mid rib which deepens at the apex • presence of gemma cups which enclose a number of gemmae • gemmae are the means of asexual reproduction • sex organs are borne on special upright branches : antheridiophores bear the antheridia whereas archegoniophores bear the archegonia BSCBT103/BZBC102-Plant Diversity 31
VEGETATIVE STRUCTURE • Ventral Surface • shows median grove • rhizoids and scales are attached • rhizoids are of two types : 1) Smooth walled (G) : inner walls smooth, living cells, fix the plant body to substratum and absorb water and soil solutes 2) Tuberculate (F,H) : peg like ingrowths in their inner walls, living in the beginning but lack protoplasm at maturity, helps to retain moisture in the ventral surface and carry water to all the absorptive parts scales are of two types : 1) Appendiculate (D): large, wedge shaped, bear an appendage at their tips 2) Ligulate (E): simple, small, tounge shaped and without appendage • scales secrete mucilage and protect the growing point from desiccation BSCBT103/BZBC102-Plant Diversity 32
BSCBT103/BZBC102-Plant Diversity 33
INTERNAL STRUCTURE • 1) Epidermal region : well marked upper and lower epidermis. upper epidermis is interrupted by barrel - shaped air pores. function of air pores is to facilitate gaseous exchange. • 2) Photosynthetic Zone : consists of regularly arranged air chambers seprated with each other by septa. a large number of photosynthetic or assimilatory filaments arise from the floor of air chambers. perform the function of photosynthesis. • 3) Storage Zone : consists of compact, colourless, thin walled parenchymatous cells which store starch grains and protein bodies. A few cells are filled with mucilage and oil bodies. BSCBT103/BZBC102-Plant Diversity 34
REPRODUCTION • Vegetative Reproduction : 1) Fragmentation 2) Adventitious branches 3) The Gemmae : - produced inside the gemma cups - these cups are produced on the dorsal surface of thallus • Sexual Reproduction : - oogamous - all the species are dioecious - male sex organs are antheridia and female sex organs are called archegonia. BSCBT103/BZBC102-Plant Diversity 36
POSITION OF SEX ORGANS • borne on special erect and stalked branches called gametophores or receptacles. • receptacle bearing antheridia is called antheridiophore and that bearing archegonia is called archigoniophore. • stalk of both antheridiophores and archegoniophores are morphologically and structurally similar. • the side corresponding to morphologically dorsal surface of thallus photosynthetic zone. • the other side of stalk corresponds to the lower ventral side of thallus. BSCBT103/BZBC102-Plant Diversity 38
THE ANTHERIDIOPHORE • differentiated into into a long stalk and a terminal disc • disc is eight lobed • upper zone of disc consists of air chambers alternating with antheridial chambers • air chambers possess assimilatory filaments which perform photosynthesis • antheridia are borne singly inside the antheridial chambers • antheridia are borne in acropetal succession BSCBT103/BZBC102-Plant Diversity 40
MATURE ANTHERIDIUM • differentiated into a short stalk and a large body • body has single layered sterile jacket • it encloses a large number of androcytes which metamorphose into antherozoid • antherozoids are small, uninucleate and biflagellate • morphologically, antheridia consists of three parts : 1) Head piece : comprising of basal bodies with two long and equal flagella attached to it 2) The nuclear portion : consisting of long narrow rod- shaped and coiled nucleus 3) The cytoplasmic portion : comprising of a thin film of cytoplasm with a few plastids and mitochondria BSCBT103/BZBC102-Plant Diversity 41
DEHISCENCE OF ANTHERIDIA • Dehisce in presence of water provided by rain or dew drops • at maturity, the pore of antheridial chamber becomes wide open through which water enters and fills the chamber • the body of antheridium encloses a mass of free antherozoids which float in a viscous fluid formed by dissolution of cell walls of androcytes • sterile jacket cells imbibe water , become softned, get disorganised • antherozoids ooze out in mass through an opening • they escape through the pore of antheridial chamber and come to the surface of disc • antherozoids swim in the film of water BSCBT103/BZBC102-Plant Diversity 43
THE ARCHIGONIOPHORE • it is the reproductive branch bearing archegonia • it is differentiated into stalk and disc • disc consists of eight lobes directed away from the centre • the archegonia develop on the upper surface of disc in arranged in eight rows • after fertilization central portion of disc buldges out and becomes convex pushing the archegonia at the periphery • the archegonia are inverted and hang downward from the tissue of disc • each archegonium has an extra sheath called perigynium • each group of archegonia is enclosed within a two lipped, curtain like involucre called perichaetium BSCBT103/BZBC102-Plant Diversity 44
STRUCTURE OF MATURE ARCHEGONIUM • mature archegonium is flask shaped • it consists of a short few celled stalk, a globular venter and a long neck • the apical part of neck is covered by 4 cover cells • the swollen venter consists of single layered jacket and encloses a venter canal cell and a large egg BSCBT103/BZBC102-Plant Diversity 45
SPOROPHYTIC GENERATION • Each sporogonium is differentiated into foot, seta and capsule • it is enclosed within a protective covering called calyptra • the other protective coverings are perigynium (pseudoinvolucre) which encloses single sporogonium and perichaetium (involucre) which covers the group of sporogonia • Foot : it anchors the sporogonium and absorbs water and nutrients from the gametophyte • Seta : it connects the capsule with foot • Capsule : it has single layered wall enclosing a mass of spores and elaters. • Elaters are hygroscopic and in this way help in spore dispersal • The sporophytic generation of lifecycle ends with the formation of spores • The spores are carried away wind or rain BSCBT103/BZBC102-Plant Diversity 48
THE YOUNG GAMETOPHYTE • Spore is the first cell of gametophytic generation • Spore has thick wall differentiated into outer, thich exine and inner, thin intine • Each spore mother cell of Marchantia produces 4 spores, out of which 2 develop into male thalli and 2 develop into female thalli • Thus Marchantia shows physiological heterospory BSCBT103/BZBC102-Plant Diversity 50
ALTERNATION OF GENERATIONS • Since the plant bodies of two generations are morphologically dissimilar, it is called heterologous type of alternation of generations - and the life cycle is diplohaplontic BSCBT103/BZBC102-Plant Diversity 52
BSCBT103/BZBC102-Plant Diversity 54 Life Cycle of Anthoceros
HABITAT • Distributed world wide • Grows in shady and moist areas of tropical and temperate regions • About 200 species, and in Pakistan 3 common species are found in Himalayas 1. Anthoceros himalayensis 2. Anthoceros erectus 3. Anthoceros chambensis BSCBT103/BZBC102-Plant Diversity 56
VEGETATIVE MORPHOLOGY • The plant body is gametophyte and consist of small, dark green, prostrate thallus • It is rosette like, and with lobes of whose margins are divided into small lobed segments • Dichotomous system is present • Surface of thallus is smooth, velvety , and contains ridges and spines • Numerous thread like rhizoids are present on ventral surface of thallus BSCBT103/BZBC102-Plant Diversity 57
INTERNAL STRUCTURE OF THALLUS • There is no internal differentiation • Parenchymatous cells are present • Each contain single lens shaped chloroplast • Deep cells contain 2-8 chloroplasts • Each chloroplast contains single pyrenoid • There are two surfaces, upper and lower epidermis • Lower epidermis contains mucilaginous cavities that opens through a pore called slime pore • In these cavities blue green alga resides. BSCBT103/BZBC102-Plant Diversity 59
REPRODUCTION • Vegetative reproduction • Sexual reproduction BSCBT103/BZBC102-Plant Diversity 61
VEGETATIVE REPRODUCTION • 1. Death of older plants: Vegetative reproduction takes place by the death of older parts. Younger parts form new thallus. • 2. Tuber: Some thallus forms tubers. These tubers are rich in stored fats and proteins. • These tubers germinate to on the margin of the lobes. They can survive long periods of drought. Tuber detach and from new plants. BSCBT103/BZBC102-Plant Diversity 62
VEGETATIVE REPRODUCTION • 1. Gemmae: Gemma are also produced on short stalks on the upper surface of the thallus. These are also act as vegetative reproductive bodies. • 2. Persistent apices : in some species the thallus dies except the apices , there are called persistent apices , they remain buried in soil and develop into new plant body during favorable conditions BSCBT103/BZBC102-Plant Diversity 64
ANTHERIDIA • Antheridia develops on cavities called antheridia chamber • Present on the dorsal surface • 1 to 25 antheridia may develop in each antheridial chambers • Mature antheridium consist of an ovoid body with stalk. • There is a mass of spermatogenous cells surrounded by jacket of sterile cells BSCBT103/BZBC102-Plant Diversity 66
DEHISCENCE • At maturity, the roof of the antheridial chamber ruptures, exposing the antheridia. The apical cell of the antheridial wall, on absorbing water, ruptures by apical aperture. The antherozoids are now liberated to the covering film of water. • The antherozoids: • The antherozoid is spindle like and biciliate. The cilia are attached to the anterior end of the body. Sometimes just near the attaching point of the flagella to the body, the blepharoplasty ( flagellated cell or basal body) is visible. The antherozoids swim in the water by the lashing moment of their flagella. BSCBT103/BZBC102-Plant Diversity 68
ARCHEGONIUM • Archegonia are produced close to the growing point. Archegonia are embedded in the tissue of the thallus. • Each archegonium consists of an egg and a ventral canal cell four neck canal cells. The canal of the archegonium is closed at the top by four cover cells. • These cells project slightly above the general surface of the thallus. BSCBT103/BZBC102-Plant Diversity 69
DEVELOPMENT OF ARCHEGONIUM BSCBT103/BZBC102-Plant Diversity 70
FERTILIZATION • Water is essential for fertilization. In the mature archegonium, the venter canal cell, neck canal cells disintegrate and form a mucilaginous mass. • It absorbs water, swells up and becomes out of the archegonial neck by pushing the cover cells apart. • This mucilaginous mass becomes continuous with the mucilage mound and in this way an open passage down to egg is formed. BSCBT103/BZBC102-Plant Diversity 71
DEVELOPMENT OF SPOROGONIUM • With the result of the first vertical division, the daughter cells are produced, which are subjected to a transverse division producing four cells of equal or unequal size • These cells again divide vertically, developing eightcelled embryo, four cells in each tier. The upper tier of four cells divides transversely. This way the three tiers of four cells each have been produced. • The lowermost tier produces the foot, the middle tier produces partly the foot and mainly the seta and the upper-most tier produces the capsule. BSCBT103/BZBC102-Plant Diversity 72
SPOROGONIUM TISSUE • In the young sporogonium, the columella consists of four vertical rows of the cells, but later on it is made up of sixteen rows of cells. • The jacket initials divide again and again periclinally producing the 4 to 6 layered wall of the capsule. • Later on, the sporogenous tissue becomes differentiated into two types of cells, i. e., (i) the sporocytes (spore mother cells) and (ii) the sterile cells (pseudoelaters). BSCBT103/BZBC102-Plant Diversity 73
LIFE CYCLE OF FUNARIA BSCBT103/BZBC102-Plant Diversity 77
SYSTEMATIC POSITION OF FUNARIA • Kingdom: Plantae • Division: Bryophyta • Class: Bryopsida • Subclass: Funariidae • Order: Funariales • Family: Funariaceae • Genus: Funaria BSCBT103/BZBC102-Plant Diversity 78
GENERAL CHARACTERS •Funaria is a genus of approximately 210 species of moss and 18 species reported from India. • Funaria hygrometrica is the most common species. Funaria hygrometrica is called “cord moss” because of the twisted seta. •The name is derived from Latin word “funis” meaning a rope • Moss plant Funaria grows in dense patches or cushions in moist shady and cool places during the rainy seasons. • It has a height of 3–5 cm, a radial symmetry with a differentiation of an axis or stem, leaves or phylloids and multicellular colorless branched rhizoids • These are primitive multicellular, autotrophic, shade loving, amphibious plants. • They reproduce by spore formation. • They have no vascular system. Root like structures called rhizoids are present. • They show alternation of generation i.e. the gametophytic stage alternates with the sporophytic stage BSCBT103/BZBC102-Plant Diversity 79
GAMETOPHORE STAGE • Gametophore is the dominant stage in the life cycle. •It is erect, leafy structure that reaches upto 3 cm height. • It has slender, cylindrical upright central axis known as cauloid on which the flat, green, lateral expansions phylloids are present. • Cauloid and phylloids are structurally not similar to stem and leaves because these are without vascular tissues and gametophytic in origin. •Plant is small about 1-3 cm long, stem is erect and branched. •It is differentiated into rhizoids, axis, and leaves. •The rhizoids are multicellular and branched. •The axis is aerial, erect, and branched. •The leaves are simple, small, and spirally arranged. •The upper leaves are large and lower leaves are crowded. BSCBT103/BZBC102-Plant Diversity 80
INTENAL STRUCTURE STEM • i. Epidermis: it is outer most single layered. It is made up of thick walled cells. • ii. Cortex: it is multilayered zone situated just below the epidermis and consists of parenchymatous cells. • iii. Central cylinder: it forms the central core of the axis and consists of vertically elongated, thin walled cell. The central cylinder provides mechanical strength to plant and help in conduction of water and mineral. BSCBT103/BZBC102-Plant Diversity 81
LEAVES • leaves are arranged on the axis in spiral fashion. The leaves are sessile, simple, green and distinct mid rib. The leaf is single layered thick except for the midrib. The central part is similar to the central cylinder of the axis. BSCBT103/BZBC102-Plant Diversity 82
REPRODUCTION • Vegitative reproduction In moss the vegetative reproduction takes place by means of various methods : • 1. By multiplication of primary protonema In Funaria spores on germination form a branched, filamentous, multicellular structure. It is pr. protonema which certain colorless separations are formed by intercalary divisions. These cells die out and break up the protonema into many fragments. These fragments grows into new protonema cotaining buds which develops into leafy gametophytes. • 2. By secondary protonema When protonema is developed by other than the germination of the spore the it is called as sec. protonema. It may develop from any detached living part of the gametophyte. BSCBT103/BZBC102-Plant Diversity 83
BY GEMMAE • Durimg unfavorable condition the terminal cells of the protonemal branches divide by trnsverse, longitudinal divisions and form green multicellular bodies of 10-30 cells. These are called gemmae. At maturity gemmae become slightly reddish brown in color. On the return of favourable conditions gemmae germinate and form new plant. • BSCBT103/BZBC102-Plant Diversity 85
CONT.. BY BULBILS • When such gemmae like structures are produced on rhizoids inside the sustratum these are called bulbils. They are devoid of chloroplasts but capable of developing them into leafy individuals under favourable conditions. • APOSPORY • Development of gametophyte from sporophyte without formation of spores is known as apospory. Any vegetative cell of the sporophyte may form green protonemal filaments which bears lateral buds later develop into leafy gametophyt. The gametophyte thus formed are diploid. Sexual reproduction in such gametophyte results in the formation of tetraploi (4n) zygote capable of bearing spores. BSCBT103/BZBC102-Plant Diversity 86
SEXUAL REPRODUCTION • Sexual reproduction is oogamous. Male reproductive structure is known as antheridium and female as archegonium. Funaria is monoecious (having male and female sex organs on the same thallus) and autoicous (antheridia and archegonia develop on separate branches of the same thallus). Sex organs are borne on leafy gametophores in terminal clusters. The main shoot of the leafy gametophore bears antheridia and act as male branch. Female branch develops as a lateral outgrowth from the base of the male branch and bears archegonia. It grows higher than the male branch. Funaria ia protandrous (antheridia mature before the archegonia). It ensures the cross fertilization. BSCBT103/BZBC102-Plant Diversity 87
MALE BRANCH OR ANTHERIDIOPHORE • Longitudinal section of male branch shows that its apex is expanded and convex shaped. It bears large number of reddish brown or orange antheridia in different stages of development. Projected antheridia are surrounded by rosette of spreading leaves called perigonial leaves. • The antheridial cluster with surrounding perigonial leaves is called perigonium. The antheridia are intermingled with large number of sterile hair like club shaped structure called paraphyses which store water, protect developing antheridia, help in photosynthesis and dehiscence of antheridia. BSCBT103/BZBC102-Plant Diversity 88
STRUCTURE OF AN ANTHERIDIUM • The antheridium is club shaped. It is differetiated into a short multicellular stalk and antheridium body which has a single layered jacket of polyhedral flattened cells. When young jacket contain chloroplast but turs orange or reddish brown at maturity. Jacket encloses a large number of androcytes (antherozoid mother cells). • At maturity the distal end of the antheridium bears one or two thick walled colorless cells called operculum. The opercular cells become mucilaginous, absorb water and swell, break connection with the neighbouring cells and form a narrow pore. Androcytes ooze out in the form of viscous fluid through this pore. • Each androcyte mother cell divides further and form two androcytes, each produces a single biflagellate sperm or antherozoids or spermatozoid. Each antherozoid is elongated, spirally coiled, biflagellated structure. BSCBT103/BZBC102-Plant Diversity 89
FEMALE BRANCH OR ARCHEGONIOPHORE • The female branch arises from the base of the male branch. Longitudinal section shows that many archegonia intermingled with paraphyses occurs at the apex. The terminal cell of paraphyses is not swollen. The cluster of archegonia is enclosed by a group of green foliage leaves called perichaetial leaves. The archegonial cluster with the surrounding perichaetial leaves is called perichaetium. • Structure of an Archegonium • A mature archegonium is flask shaped structure. It remains attached to the female branch by a massive stalk. It consists upper elongated slender neck and basal globular portion called venter • The neck is slightly tubular, twisted, single layered and consists of six vertical rows of neck cells which enclose an axial row of ten or more vertical neck canal cells. The venter wall is two layered and encloses venter canal cell and egg cell. Venter canal cell is situated just below the neck canal cells. BSCBT103/BZBC102-Plant Diversity 91
FERTILIZATION • In Funaria water is essential for fertilization. The operculum cells of the antheridium rupture and releases mass of antherozoids. When archegonium reaches at maturity the neck canal cells and venter canal cell disintegrate to form a mucilaginous mass. It absorbs water, swells up and comes out of the archegonial mouth by pushing the cover cells apart. This mucilaginous mass consists chemical substance mainly sugars. • The cover cells of the neck separate widely from each other and form a passage leading to the egg. Many antherozoids enter the archegoniial neck because of chemical response but only one of them fuses with the egg to form zygote. BSCBT103/BZBC102-Plant Diversity 93
SPOROPHYTIC PHASE • Zygote is the first cell of the sporophytic phase. Development of the sporophyte takes place within the venter of the archegonium. • Structure of Sporophyte • The sporophyte is semi-parasitic in nature. A mature sporophyte can be differentiated into three distinct parts: • FOOT It is the basal portion of the sporogonium. It functions as an choring and absorbing organ. • SETA • It is long, slender, stalk like hygroscopic structure. It bears the capsule at its tip and raises it above the apex of leafy gametophores. Its internal structure is similar to axis. It is mechanical in function and also conducts water and nutrients to the developing capsule. • CAPSULE • It is the terminal part of sporophyte and is green in color when young but on maturity becomes bright orange coloured. It is covered by a cap like structure called calyptras. BSCBT103/BZBC102-Plant Diversity 94
INTERNAL STRUCTURE OF THE CAPSULE • Longitudinal section of the capsule shows that it can be differentiated into three distinct regions • APOPHYSIS • It is the sterile part of the capsule. It is bounded by the single layered epidermis which is interrupted by stomata. The stomata have single ring like guard cells. Below the epidermis is spogy parenchyma. The central part of the apophysis is made up of elongated thin walled cells forming a conducting strand. It is called neck of the capsule. It is the photosynthetic region and connects seta and capsule. • THECA • It is the middle, slightly bent spore bearing region of the capsule which lies in between the apophysis and operculum. L.S. passing through theca shows following regions: epidermis, hypodermis, spogy parenchyma, air spaces, spore sacs and collumela. When young the cavity of spore sac is filled with many spore mother cells. At maturity the SMC divide meiotically and form haploid spores. The spongy parenchyma consists of two to three layers of loosely arranged chlorophyllous cells. Collumela is the central part made up of compactly arranged colorless parenchymatous cells which helps in conduction of water and mineral. BSCBT103/BZBC102-Plant Diversity 96
CONT… • OPERCULUM • It is the upper region of the capsule. It is dome shaped and consists of four to five layers of cells. The outermost layer is thick walled and called epidermis. • Operculum is differentiated from theca by a well marked constriction below which is a diaphragm or rim. Above the rim is annulus which consists of 5-6 superimposed layers of cells. Below the operculum lies the peristome. It consists of two rings of radially arranged peristomal teeth. In each ring there are sixteen teeth. Teeth are not cellular but stripes of the cuticle. BSCBT103/BZBC102-Plant Diversity 97
DEHISENCE OF THE CAPSULE • Funaria is a stegocarpous moss (dehisce along pre determined line. It occurs by breaking off of annulus. The thin walled cells of annulus break away, the operculum is thrown off and the peristome teeth are exposed. The lengthening and shortening of the outer peristome teeth help in the dispersal of spores BSCBT103/BZBC102-Plant Diversity 99
STRUCTURE AND GERMINATION OF SPORES • Each spore is spherical and surrounded by two wall layers. The outer wall is thick, smooth, brown and known as exosporium. While the inner wall is thin, hyaline called as endosporium. Spore wall encloses single nucleus, chloroplast and many oil globules. Under favourable conditions spores germinates, exosporium ruptures and endosporium • forms one or two germ tubes. Each germtube is multicellular, green whch grows into protonema. BSCBT103/BZBC102-Plant Diversity 100
Multiple Choice Questions Q1 – The thalloid plant body is found in a. Marchantia b. Sphagnum c. Funaria d. Salvinia B Q2 – Peat moss is used for transporting plants to distant places because a. it is hygroscopic b. it reduces transpiration c. it is easily available d. it serves as a disinfectant BSCBT103/BZBC102-Plant Diversity 102
Multiple Choice Questions Q3 – Find the true statement about bryophytes a. they have chloroplasts b. they have archegonia c. they are thalloid d. all of the above Q4 – A characteristic feature of bryophytes is a. a dominant and parasitic sporophyte b. a dominant and spore-producing gametophyte c. a small sporophyte phase, which is dependent on the gametophyte d. sporophytes stay for a longer duration C BSCBT103/BZBC102-Plant Diversity 103
Multiple Choice Questions Q5 – The antherozoids of Funaria are a. uniflagellate b. biflagellate c. multiflagellate d. do not have flagella Q6 – In mosses, meiosis takes place during a. gamete formation a b. ntheridia and archegonia formation c. spore germination d. spore formation BSCBT103/BZBC102-Plant Diversity 104
Multiple Choice Questions Q7 – The basal swollen portion of the archegonium is: a. Venter b. Neck c. Jacket d. Oospere Q8- Which plant does belong to Anthoceropsida? a. Funaria, b. Polytrichum c. Porella d. Anthoceros BSCBT103/BZBC102-Plant Diversity 105
Multiple Choice Questions Q9 – Meristematic tissues are present in: a. Marchantia b. Polytrichum c. Porella d. Anthoceros Q10 – Which of the followings is absent in bryophytes? a. Archegonia b. Oosphere c. Zoospore d. Antheridia BSCBT103/BZBC102-Plant Diversity 106
Multiple Choice Questions Q11 – A structure is present in the centre of the capsule called: a. elaters b. spores c. columella d. pseudoelaters Q12-A narrow region encircles the columella. This region contains spores and: a. elaters b. spores c. columella d. pseudoelaters BSCBT103/BZBC102-Plant Diversity 107
Multiple Choice Questions Q13 Endothecium divides to form: a. elaters b. spores c. columella d. pseudoeaters Q14– The archegonia and bracts forms structure called: a. bracts b. paraphylls c. involucre d. Gemma BSCBT103/BZBC102-Plant Diversity 108
Multiple Choice Questions Q15-Elaters are present in sporogonium of a. Riccia b. Marchantia c. Sphagnum d. Selaginella Q16–Sporogenous tissue is of amphithecial origin in a. Riccia b. Anthoceros c. Marchantia d. Funaria BSCBT103/BZBC102-Plant Diversity 109
Multiple Choice Questions Q17 – The air cavities in the capsule of moss are partitioned with delicate strands of cells. These are called a. Trabeculae b. Compartments c. Partitions d. Septa Q18 – The dehiscence of moss capsule takes place by the rupture of the following a. Calyptra b. Operculum c. Peristome d. Annulus BSCBT103/BZBC102-Plant Diversity 110
Multiple Choice Questions Q19 In moss sporophyte, following is absent a. Foot b. Seta c. Columella d. elaters Q20 – Spore mother cell in Bryophytes is- a. Haploid b. Diploid c. Triploid d. Tetraploid BSCBT103/BZBC102-Plant Diversity 111
BSCBT103/BZBC102-Plant Diversity 112 Thank You

JULY-DEC_2022_BSCBT_1_SEM_V9_BSCBT103_BSCBT103BZBC102___Unit_3_PPT.pptx

Check these out next

JULY-DEC_2022_BSCBT_1_SEM_V9_BSCBT103_BSCBT103BZBC102___Unit_3_PPT.pptx

Recommandé

Contenu connexe

Similaire à JULY-DEC_2022_BSCBT_1_SEM_V9_BSCBT103_BSCBT103BZBC102___Unit_3_PPT.pptx(20)

Dernier(20)

JULY-DEC_2022_BSCBT_1_SEM_V9_BSCBT103_BSCBT103BZBC102___Unit_3_PPT.pptx