1st PUC Biology Question Bank Chapter 3 Plant Kingdom

Karnataka 1st PUC Biology Question Bank Chapter 3 Plant Kingdom

1st PUC Biology Plant Kingdom One Marks Questions and Answers

Question 1.
Which group of plants are commonly called Amphibians of the Plant Kingdom?
Answer:
Bryophytes.

Question 2.
Why the Plant body of Bryophytes is Gametophyte?
Answer:
Plant body of bryophyte produces gametes in their sex organs.So it is gametophyte.

Question 3.
Name the male sex organ of a Bryophyte.
Answer:
Antheridium.

Question 4.
Name the class to which Riccia belongs.
Answer:
Hepaticopsida.

Question 5.
Name the organ that fixes the plant body of Riccia to the on soil.
Answer:
Rhizoid.

Question 6.
What is a sporophyte ?
Answer:
It is the plant body or generation that produces spores by asexual method.

Question 7.
What is thallus?
Answer:
Thallus is the undifferentiated plant body characteristic of bryophytes, lower pteridophytes and algae.

Question 8.
Write a note on Archegonia.
Answer:
These are flask shaped female sex organs found in the gametophyte of bryophytes, pteridophytes and gymnosperms.

Question 9.
Assign the following plants to their respective groups,
(i) Anthoceros
(ii) Funaria.
Answer:
(i) Anthoceros – Class : Anthoceratopsida, Division : Bryophyta.
(ii) Funaria – Class : Bryopsida, Division : Bryophyta.

Question 10.
Give reason for the following:
Bryophytes require water for reproduction.
Answer:
The sperms of bryophytes are motile, hence require water for swimming.

Question 11.
Give reason:
Bryophytes are amphibians of the plant kingdom.
Answer:
Even though bryophytes live on land they need water for fertilization.

Question 12.
What are Tracheophytes?
Answer:
They are the group of plants which contain xylem and phloem.

Question 13.
Which is the dominant phase in the life cycle of Pterido’phyta?
Answer:
Diploid sporophyte is the dominant phase in the life cycle of Pteridophyta.

Question 14.
What is the other name of ProthaUus?
Answer:
Gametophyte.

Question 15.
What is an Archegonium?
Answer:
Female sex organ of Bryophytes, pteridophytes and Gymnosperms is called archegonium. Egg is produced in its venter region.

Question 16.
Define circinate vernation.
Answer:
Circinate vernation is the spring like coiled nature of young leaves and branch tips of ferns.

Question 17.
Give reason:
Pteridophytes are lower vascular cryptogams.
Answer:
They possess xylem and phloem but are seedless plants.

Question 18.
What are Strobili?
Answer:
The reproductive organs of gymnosperms are called strobili cones.

Question 19.
Why the sporophyte of Gymnosperm is heterosporous?
Answer:
Sporophyte produces two types of spores like smaller microspores and larger megaspores, so it is heterosporous.

Question 20.
Mention the class of Cycas.
Answer:
Cycadopsida.

Question 21.
What are mega and microsporophylls ?
Answer:
Megasporophylls are the leaf like lateral structures of the female cone. They produce megasporangia or ovules. Microsporophylls are the flattened leaf like extensions of male cone. They produce microsporangia.

Question 22.
What is a Mycelium?
Answer:
Mycelium is the plant body of fungi. It comprises of hyphae.

Question 23.
Which is the cell wall material of Fungi?
Answer:
Chitin (fungal cellulose).

Question 24.
Define the branch of study known as Mycology.
Answer:
Mycology is the study of fungi.

Question 25.
Why are deuteromycetes named Imperfect fungi?
Answer:
Deuteromycetes are termed Imperfect fungi, because, only their asexual reproductive stages are known.

Question 26.
Why Bryophytes are called non-vascular cryptogams and as?
Answer:
Bryophytes do not contain xylem and phloem tissues so they are non-vasular and as they do not produce visible flowers, so they are cryptogams.

Question 27.
What are vascular cryptogams?
Answer:
Plants that contain xylem and phloem tissues in their organs, are vascular plants and plants that do not produce flowers and fruits are called as cryptogams.

Question 28.
Give one example of Lycopsida.
Answer:
Lycopodium.

Question 29.
Both gymnosperms and angiosperms bear seeds, then why are they classified separately?
Answer:
The seeds of gymnosperms are naked whereas the seeds of angiosperms are covered by fruits.

Question 30.
How would you distinguish monocots from dicots?
Answer:
Dictos are characterized by having two cotyledon in their seeds while the monocotyledons have only one.

Question 31.
Food is stored as Floridean starch in rhodophyceae. Mannitol is the reserve food of which group of algae?
Answer:
Phaeophyceae.

Question 32.
The plant body in higher plants is well differentiated and well developed. Roots are the organs used for the purpose of absorption. What is the equivalent of roots in the less developed lower plants? .
Answer:
Rhizoids.

Question 33.
Why are bryophytes called amphibians of plant kingdom?
Answer:
Bryophytes are called amphibians of plant kingdom they require water for maintaining the cells from dehydration and swimming of sperms to the archegonia at the time of fertilization.

Question 34.
Name the amphibians of the Plant Kingdom.
Answer:
Bryophytes.

Question 35.
What is Thallus?
Answer:
Dorsiventrally flattened plant body without a root, stent and leaf differentiation is called Thallus.

Question 36.
Which phase is predominent in the life cycle of bryophyte?
Answer:
Gametophyte.

Question 37.
Name a gymnosperm with vessels, in the Xylem.
Answer:
Gnetum.

Question 38.
Name a parasitic angiosperm.
Answer:
Cuscuta.

1st PUC Biology Plant Kingdom Two Marks Questions and Answers

Question 1.
List any four characteristics of Protista.
Answer:
(i) Protists are unicellular eukaryotes and they contain true nucleus and cytoplasmic organells like mitochondria, golgi body etc.
(ii) They show different types of nutrition. Some are photoautotrophs while others are heterotrophic,
Heterotrophs are saprophytes or parasites. Some protists show animal like holozoic nutrition.
(iii) Some protists possess locomotory organellas like pseudopodia, flagella, cilia etc.
(iv) Protists show both asexual and sexual reproduction, characters.

Question 2.
List the general characters of algae.
Answer:
(i) Algae are chlorophyllous, photosynthetic aquatic organisms and they are eukaryotes.
(ii) They are either unicellular, colonial or multicellular. The multicelluar algae produce branched or unbranched filaments.
(iii) Cell wall is made up of cellulose.
(iv) Photosynthetic pigments are in plastids.
(v) They show both asexual and sexual reproductions.
(vi) Asexual reproduction is by the formation of spores and sexual reproduction is by isogamy or anisogamy.

Question 3.
Name the class to which of the following belong. ,
(a) Funaria
(b) Anthoceros
(c) Riccia
(d) Polytrichum.
Answer:
(a) Funaria – Bryopsida.
(b) Anthoceros – Anthocerotopsida.
(c) Riccia – Hepaticopsida.
(d) Polytrichum – Musci (bryopsida).

Question 4.
What is the basis of classification of algae?
Answer:
Algae are classified based on pigments & colour of the thallus.
(a) Chlorophyceae: Green algae due to the presence of the pigments chlorophyll a and b.
(b) Phaeophyceae: Brown algae due to the presence of the pigments chlorophyll a and c and fucoxanthin. (xanthophyll).
(c) Rhodophyceae: Red algae due to the presence of phycoerythrin (red colour) and chlorophyll a and d.

Question 5.
Give an example of plants with
(a) Haplontic life cycle
(b) Diplontic life cycle.
Answer:
(a) Haplontic life cycle: Spirogyra, Volvox.
(b) Diplontic life cycle : Fucus, seed plants.
(c) Haplodiplontic life cycle: Marchantia, Fern.

Question 6.
Match the following: (column I with column II):

Column I	Column II
(a) Chlamydomonas	(i) Moss
(b) Cycas	(ii) Pteridophyte
(c) Selaginella	(ii) Algae
(d) Sphagnum	(iv) Gymnosperm

Answer:
a – iii; b – iv; c – ii; d – i.

Question 7.
Most algal genera show haplontic life style. Name an algae which is,
(a) Haplodiplontic
(b) Diplontic.
Answer:
Haplodiplontic life style: Dictyota, Ulva, Polysiphonia.
Diplontic life style: Fucus.

Question 8.
In bryophytes, male and female sex organs are called as and ………..
Answer:
antheridia, archegonia.

Question 9.
Distinguish between Green algae and brown algae.
Answer:

Green algae:	Brown algae :
•   Mostly fresh water. •    Chlorophyll a and chlorophyll b present. •    Fucoxanthin is absent. •    Reserve food material is starch.	•      Mostly marine •      Chlorophyll a and chlorophyll c present •      Fucoxanthin is present. •      Reserve food material is laminarin.

1st PUC Biology Plant Kingdom Three Marks Questions and Answers

Question 1.
What is heterospory? Briefly comment on its significance. Give two examples.
Answer:
Heterospory is the occurrence of two types of spores, namely microspores and megaspores, that give rise to male and female gametophytes respectively.
Importance : Heterospory has lead to seed habit in plants through.
(i) Reduction in size of gametophytes.
(ii) Dependence of gametophytes for nourishment on sporophyte
(iii) Retention of female gametophyte in megasporangium.
Example: Salvinia, Selaginella.

1st PUC Biology Plant Kingdom Five Marks Questions and Answers

Question 1.
When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?
Answer:
(i) Liverwort: Capsule part of sporophyte at the time of spore formation.
(ii) Moss : Capsule part of sporophyte at the time of spore formation.
(iii) Fern : Sporangia at the time of spore formation.
(iv) Gymnosperm: Microsporangium at the time of microspore or pollen formation and ovule or magasporangium at the time of megaspore formation.
(v) Angiosperm. Microsporangium and ovule or megasporangium at the time of microspore (pollengrain) and megaspore formation.

Question 2.
Name three groups of plants that bear archegonia. Briefly describe the life cycle of anyone of them.
Answer:
Bryophytes, pteridophytes and gymnosperms bear archegonia.

In modern days there are few additional criteria and methodologies which are used in classifying the organisms to avoid the problems of establishing evolutionary relationships.
(a) Numerical taxonomy: The application of simple mathematical principles or techniques or methods in taxonomical studies of plants may be defined as numerical taxonomy.
(b) Chemotaxonomy: The classification based on the basis of chemical constituents present in plants is knoi as chemotaxonomy.
(c) Cytotaxonomy: The branch of taxonomy principally based on cytology is known as totaxoncn. It maiiba chromosome morphokgies, chromosome behaviour in meiosis c.
(d) Cladlatic taxonomy: It is based exclusively on evolutionary relationship ie., phylogeny.

Question 3.
Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in a dicot, leaf ceil of a moss; prothallus cell of a fern; gemma cell in Marchantia; meristem cell of a monocot, ovum of a liverwort, and zygote of a fern.
(a) protonemal cells of a moss = haploid.
(b) primary endosperm nucleus of a dicot = diploid.
(c) leaf cell of a moss = haploid.
(d) prothallus cell of a fern = haploid.
(e) gemma cells in Marchantia = haploid.
(f) meristem cell of a monocot = diploid.
(g) ovum of a liverwort = haploid.
(h) Zygote of a fern = diploid.
Answer:
(i) protonema: The predominant stage of the life cycle of a moss is the gametophyte which consists of two stages. The first stage is protonema stage, which develops directly from a spore. It is a creeping green branched form frequently a filamentous stage.

(ii) antheridium: Antheridium is a haploid structure producing and containing male gametes. Antheridium is the male sex organ of lower plants such as pteridophytes, bryophytes etc., Antheridium produces antherozoids. These antherozoids are released into surrounding atmosphere so such that they come in contact with the female sex organs (archegonium).

(iii) archegonium: Archegonium is a multicellular organ of gametophyte phase of certain lower plants. It produces and contains ovum or female gametophyte. Archegonium is the female sex organ. Archegonium is present on the surface of the plant thallus. Archegonium is flask shaped. When Antherozoids come in contact with eggs in Archegonium they form Zygotes.

(iv) diplontic: Type of life cycle in plants where diploid sporophyte is the dominant, photosynthetic independent phase of the plant. . The gametophytic phase is represented by the single to few-called haploid gametophyte. All seed bearing plants (gymnosperms and angiosperms) follow this pattern.

(v) sporophyllr The sporophytes of pteridophytes bear leaf-like appendages called sporophylls. In some cases sporophylls may form distinct compact structures called strobili or cones. The sporophyll bear spore producing structures called sporangia.

(vi) isogamy: Isogamy is a form of sexual reproduction involving fusion of two gametes similar in size and appearance. Chlamydomonas gametes have the same size and are flagellated Spirogyra’s gametes are similar in size but don’t have flagella.

Question 5.
Differentiate between the following:
(i) Red algae and brown algae.
(ii) Liverworts and moss.
(iii) Homosporous and heterosporous pteridophyte.
(iv) Syngamy and triple fusion.
Answer:
(i) Brown algae:-
(a) Their colour is due to die presence of the Brown pigment, fucoxanthin.
(b) Chlorophyll a and c are present in brown algae.
(c) They contain stored food mannitol and laminarin.
(d) Their cel! walls are made up of cellulose and algin.

Red algae:-
(a) Their colour due to presence of phycoerythin, Chlorophyll a and d.
(b) Their cell wall is made up of cellulose, pectin and muco polysaccharides,
(c) Flagella are absent.
(d) Reserve food material is floridean starch.

(ii) Liverworts:
(a) Liverworts are dorsiventral, thalloid or foliose.
(b) Asexual reproduction is by fragmentation of thalli.
(c) Rhizoids are unicellular.
Example: Marchantia.

Moss:
(a) Gametophytes consists of two stages (Protonema and leafy stage). Mosses are erect forms.
(b) Asexual reproduction is by fragmentation and budding in secondary protonema.
(c) Rhizoids are multicellular.

Example: Funaria, polytrichum.
(iii) Homos porous:
(a) All the spores produced are of similar type.
(b) Majority of pteridophytes are homosporous.
Example: psilotum.

Heterosporous:
(a) Two kinds of spores macro and microspores are produced.
(b) Veiy few heterosporous pteridophytes are present.
Example: selagnella.

(iv) Syngamy:
(a) Male gamete fuses with the egg cell to form diploid zygote.
(b) Zygote develops into an embryo.

Triple fusion:
(a) One male gamete fuses with diploid secondary nucleus to from PEN.
(b) Second nucleus fuses with egg to form diploid zygote.
(c) PEN is triploid.
(d) PEN develops into endosperm which provides nourishment to the developing embryo.

Question 6.
Describe the important characteristics of gymnosperms.
Answer:
Gynmosperms represent primitive phaencrogams (flowering plants) or spermatophytes.
They are generally regarded as ‘naked seeded plants’ due to the presence of exposed seeds without being protected by ovary wall as there is no well defined carpel.

Gymnosperms are distributed throughout the world, represented in tropical and temperate forest, and dominating in mountainous ranges.

The group comprises nearly seven hundred species. They exhibit diverse habits showing presence of woody climbers (lianas), shrubs and trees.

General features:

1. The life cycle has a distinct, dominant, diploid, asexual phase represented by the well differentiated evergreen woody plant, which is known as sporophyte.

2. The spocophyte is hetcrosporous hearing microspores and megaspores within microspongia and megasporana respectively. These structures occur on leaf like microsporophylLs and megaspocophylls. These are further organised into fertile structures callad sirobili or cones.

• The dominant phase in the life cycle is the independent sporophytic plant.
• Meiosis occurs in the spore mother cells during spore formation and the gametophyte is short-1 and is. dependent on the sporophyte.
  e.g. Fucus (brown alga), gymnosperms and angiosperms.

1st PUC Biology Plant Kingdom Text Book Questions and Answers

The Kingdom Metaphyta also called Kingdom Plantae, is a polyphyletic group which means that it includes different groups of plants and have evolved from different protistan ancestors. The characteristic features of the Kingdom Plantae (Metaphyta) are:
1. All plants are multicellular, eukaryotic, photosynthetic and producers.
2. The cells have a cell wall composed chiefly of cellulose or both cellulose and pectin.
3. The plant body is thalloid (Bryophyta) or differentiated into root, stem and leaves (Tracheophyta).
4. They are mostly autotrophic and have green, brown, red, and other coloured pigments.
5. In higher forms, tissues and organs are well marked for different functions.
6. They are either non-vascular (eg. Bryophytes) or vascular (eg. Tracheophytes).
7. Mostly they have two stages in their life cycle-a haploid gametophytic (gameter producing generation and a diploid sporophytic (spore producing) generation and undergoing alternation of generations.

Various systems of biological classification:
Taxonomists have proposed different systems of classification for the living organisms from time to time. The systems are mainly of three categories:
(1) Artificial system: It is the system based on one or a few easily recognisable characters. This system was first proposed by Theophrastus and later Artistotle and Linnaeus used this system of classification in their work.
(2) Natural system: It is based on all the important characteristics of organisms and their natural relationships. Bentham and Hooker used this system in classifying the plant kingdom.
(3) Phylogenetic system: This system is based on the characteristics as well as evolutionary relationships of organisms which is called as phytogeny.
A. W. Eichler used this classification for the first time and later Engler and Prantl used this classification in their work On classifying the plants.

Phenetic classification:
In modem days there are few additional criteria and methodologies which are used in classifying the organisms to avoid the problems of establishing evolutionary relationships.
(a) Numerical taxonomy: The application of simple mathematical principles or techniques or methods in taxonomical studies of plants may be defined as numerical taxonomy.
(b) Chemotaxonomy: The classification based on the basis of chemical constituents present in plants is known as chemotaxonomy.
(c) Cytotaxonomy: The branch of taxonomy principally based on cytology is known as
cytotaxonomy. It numbers chromosome morphologies, chromosome behaviour in meiosis etc.
(d) Cladistic taxonomy: It is based exclusively on evolutionary relationship ie., phytogeny.

Classification Of Plant Kingdom:

Plant kingdom has been classified in Various ways by different scientists. One of the most accepted classification is as follows:

A. Chlorophyceae (Green algae):-

• These are mainly fresh-water forms and a few are marine ; some are also terrestrial, living on moist soils, wet rocks or tree trunks.
• The characteristic pigments are chlorophyll – a, chlorophyll – b, carotene and xanthophyll, similar to higher plants. The reserve food materials are in the form of pyrenoids (starch and proteins) and some oil droplets.
• The thallus organisation is as follows:

Unicellular, motile – Chlamydomonas Unicellular,
non-motile – Chlorella Colonial,
motile – Pandorina, Eudorina Colonial,
non-motile – Hydrodictyon Unbranched,
filamentous – Spirogyra, Ulothrix Branched,
filamentous – Qladophora Sheet-like – Ulva
Coenocytic – Voucheria Heterotrichous – Char a, Nitella

• Cell wall is made of cellulose and pectin.
• Cells possess one or more chloroplasts (of various shapes in different species). eg : Cupshape, spiral shape, star shape etc.
• Vegetative reproduction is by fragmentation, and asexual reproduction is by spores of different types.
• Sexual reproduction ranges from isogamy, anisogamy to oogamy.
• Life cycle may be haplontic (Chlamydomonas), diplontic (Codium) or haplo-diplontic (Cladophora and Ulva).

B. Phaeophyceae (Brown algae):-

• These are marine algae living in colder seas.
• The thallus organisation is as follows :

Branched filament – Ectocarpus
Plant body well differentiated and large -Macrocystis, Laminaria, Sargassum.
Plant body is differentiated into a hold fast, stem-like stipe and leaf-like lamina blade. Most of them are lithophytes and a few are epiphytes.
Sargassum and Fucus are free-floating.

• The larger brown algae possess air-bladder for floating.
• Cell wall is made of cellulose and often covered by phycocolloids like alginic acid and fucinic acid.
• Characteristic brown colour is due to fucoxanthin and other pigments that include chlorophyll-a, chlorophyll-c carotene and xanthophyll.
• The reserve food materials are laminar in (starch) and mannitol.
• Vegetative reproduction occurs by fragmentation or adventitious branching.
• Asexual reproduction is by formation of motile and non-motile spores.
• Spores are pyriform and possess two laterally inserted flagella.
• Sexual reproduction varies from isogamy, anisogamy to oogamy, zygotic meiosis is generally absent and alternation of generations is common.

C. Rhodophyceae (Red Algae):-

• They are mostly marine and a few (e.g., Batrachospermum) arc fresh-water forms.
• The thallus organisation is as follows:

Unicellular – Porphyridium
Palmelloid – Asterocustis
Filamentous – Polysiphonia
Parenchymatous sheet like – Porphyra
Ribbon like – Chondrus
Lace-like (network) – Gelidium

• The characteristic red colour is due to r-phycoerythrin. Other pigments include r-phycocyanin, chlorophyll-a, chlorophyll-d and B-carotene.

• Cell wall is composed of cellulose, pectin and some mucopolysaccharides, which are collectively called phycocolloids (agar, carrageenin, etc.).

• Some red algae (e.g., Corallina) are calcareous and form hard, stony thallus due to*the deposition of calcium carbonate over the cell wall.

• The reserve food material is floridean starch, which resembles glycogen.

• Vegetative reproduction occurs by fragmentation and asexual reproduction by non-motile spores (monospores, carpospores and tetraspores).

• Sexual reproduction is oogamous, male sex organ is called spermatangium and female sex organ is called carpogonium, the zygote forms a carposporophyte in some and such forms show alternation of generations.

Division Ii : Bryophyta

Bryophytes are generally regarded as amphibians of the plant kingdom, as the exhibit aquatic as well as terrestrial features during their life cycle. Though the plant body on many occasions exhibit terrestrial habitat, invariably it requires water for bringing out sexual reproduction, to complete their life cycle.
(1) They are non-vascular plants, exhibiting amphibious habitat;
(2) Gametophytic phase of the life cycle is represented’by multicellular, haploid thallus, which is called gametophyte.
(3) Gametophytic plant body bearing male and female sex organs, represents the dominant phase of life cycle unlike in higher plants.
(4) Gametophyte is autotrophic and independent in nature. .
(5) The gametophyte produces sex organs, the antheridia and the archegonia which are multicellular.
Antheridia may be embedded within the thallus or may be specifically located at the tips of the gametophyte. It produces biciliate curved antherozoids. Archegonia is a flask like structure. It bears a basal bulbous ventor and a narrow, hallow structure at .it is summit called neck. Within the venter, the female gamete or egg is situated along with a venter canal cell. The neck shows neck cells, neck canal cells and cover cells.
(6) Fertilisation takes place in the presence of water, leading to formation of a zygote which later develops into multicellular embryo Hence, the group is treated under embryophyta. i
(7) Sexual reproduction is always of oogamous type.
(8) Embryo develops into a diploid sporophyte consisting of foot, Seta and capsule, which is dependent on gametophyte.
(9) Diploid sporophyte reproduced by formation of haploid spores (meiosis occur during spore formation). The spore germinates and produces gametophyte.
(10) In their life cycle, such distinct heteromorphic alternation of generatidns is shown by the members.

A. Liverworts:
Liverworts grow on moist, cool and shady habitats.

• The plant body is thalloid as in Riccia and Marchantia.
• The thallus is dorsoventrally flat and dichotomously branched, it is closely appressed to the substratum.
• The leafy members (e.g. porella) have tiny leaf-like appendages in two rows on the stem-like structure.
• Vegetative reproduction is by fragmentation of the thallus or by the formation of gemmae. Each gemmae grows into a new plant.
• Sex organs are antheridia (male) and archegonia (female) and the plant may be monoecious (Riccia) or dioecious (marchantia).
• The zygote formed as a result of fertilization develops into an embryo which gives rise to the sporophyte.
• It is the simplest in Riccia (embedded in the thallus itself) and in advanced/ higher bryophytes, the sporophyte is differentiated into foot, seta and capsule.
• The spores are produced in the capsule, where the spore mother cells undergo meiosis to produce the spores.
• Spores on liberation germinate into the thalloid gametophyte.

B. Mosses:-

• The plant body is a leafy gametophyte which has multicellular rhizoids with oblique septa, a stem-like cauloid and leaf-like phylloids.

• It is monoecious and bears antheridia and archegonia on the same-plant, but on different branches.

• The male branch is called perigonium and has a cluster of antheridia interspersed with paraphyses and protected by perigonial leaves.

• Each antheridium is club-shaped and produces a number of biflagellated antherozoids.

• The female branch is called perichaetium and bears a number of archegonia interspersed with paraphyses and protected by perichaetial leaves.

• Each arehegonium is a stalked flask-shaped structure with a swollen is it ventre and a long neck.

• The ventre encloses a female gamete and a ventre canal cell, while the neck has 6-10 neck canal cells.

• At maturity, the neck canal cells and the ventre canal cell disintegrate with the help of water and form a mucilaginous mass containing sugar, that attracts the male gametes to the female gamete.

• The zygote forms a sporophyte which is differentiated into foot, seta and capsule.

• The capsule encloses two spore sacs, where spores are formed.

• The spores on liberation germinate into a protonenia (which resemble the algae).

• Protonema reproduces vegetatively by fragmentation into new protonema and the buds formed on the protonema on separation grow into’leafy gametophyte.

• The life cycle of a bryophyte is described as haplo-diplontic.

Division In: Pteridophytes

This group represents the primitive tracheophytes, which are non-flowering plants. They are also known as vascular cryptogams, due to the presence of conducting tissues namely xylem and phloem. They are also regarded as seedless vascular plants or seedless embryophytes. There are more than 400 genera and about 10,500 species in this group.
Pteridophytes are characterised by the following features:
1. Their life cycle, comprises distinct diploid phase represented by sporophyte and a haploid phase by gametophyte exhibiting heteromorphic alternation of generations.

2. Sporophyte represents the dominant phase of life cycle, which is an entirely independent plant body. It bears roots, stems and leaves. It reproduces asexually by sporangia.

3. The sporangia may be arranged in specific groups called sorus. In a few cases, sporangial structures aggregate on a specialised reproductive structure called strobilus or cone.

4. In sporophyte the vegetatiye structure show highly specialised conducting tissues namely xylem and phloem. These tissues are organised into the vascular system called stele.

5. The gametophyte though independent is short lived. It bears both male and female reproductive structures namely, antheridia and archegonia respectively.

6. Gametophyte thus show oogamous types of sexual reproduction like Bryophytes. Water is essential for fertilisation. The zygote develops into a multicellular embryo. Hence, the group is treated under embiyophyta siphonogama (Siphonogama – as it possess vasculature).

Classification:
Pteridophytes are categorised into four major classes:
1. C: Psilotopsida: eg: Psilotum
• Members lack true roots in this class.

2. C: Lycopsida: eg: Lycopodium, selaginella
• Members possess distinct root, stem and leaves.
• They are either homosporous or heterosporous.

3. C: Sphenopsida: eg: Equisteum
• Members possess articulated or jointed stems bearing whorls of scaly leaves.

4. C: Pteropsida: eg: Pteris, Adiantum,- Nephrolepis
• Generally known as ferns.
• Members exhibit a plant body like Angiosperms.

Division Iv: Gymnospermae (gymno-naked: sperms-seed)

Gymnosperms represent primitive phaenerogams (flowering plants) or spermatophytes. They are generally regarded as ‘naked seeded plants’ due to the presence of exposed seeds without being protected by ovary wall as there is no well defined carpel.

Gymnosperms are distributed throughout the world, represented in tropical and temperate forest, and dominating in mountainous ranges.

The group comprises nearly seven hundred species. They exhibit diverse habits showing presence of woody climbers (lianas), shrubs and trees.

General features:
1. The life cycle has a distinct, dominant, diploid, asexual phase represented by the well differentiated evergreen woody plant, which is known as sporophyte.

2. The sporophyte is heterosporous bearing microspores and megaspores within microspongia and megasporangia respectively. These structures occur on leaf like microsporophyils and megasporophylls. These are further organised into fertile structures called strobili or cones.

3. Sporophyte shows the presence of a taproot system which is well developed. The stem possesses branches which are dichotomies. Leaves are well developed and are dimorphic (two types of leaves): viz,

• Green photosynthetic leaves (Foliage).
• Brown coloured scale leaves.

4. Microspore develops into male gametophyte and megaspore produces female gametophyte.
These gametophytes represent the haploid phase and are highly inconspicuous comparison with sporophytic generation.

5. Female gametophyte is enclosed within a megasporangium that intum is covered by an integument. Such an integumented megasporangium possessing the female gametophyte is called ovule.

6. Endosperm or female gametophyte is regarded as per the fertilised product and is haploid.

7. Semigerminated pollengrains (microspores) are liberated from the microsporangium and are pollinated on to the ovule. In the ovule they sit in the pollen chamber and complete germination by producing a pollen tube which enters into nucellus, female gametophyte! endosperm and ultimately enters archegorria and reach the egg located in the ventre region. The tip of the pollen tube bursts releasing sperm cells which fuse with egg to form a zygote. (Simultaneously 2-3 archegonia in a ovule fertilised).

8. Embryogeny takes place where only one functional embryo is formed along with seed development.

9. The seed germinates to form a new sporophyte.

Classification:
According to Sporne (1965), Gymnosperms are classified into 3 classes:
1. Class Cycadopsida: eg: Cycas, Zamia.
2. Class Coniferopsida: eg: Pinus, Aracauria, Taxus, Thuja, Sequoia.
3. Class Gnetopsida: eg: Gnetum, Ephedra, Welwitschia.

Division V: Angiospermae (angio-covered; sperma-seed)
Angiosperms are a group of flowering plants which produce hidden seeds or enclosed seeds within the fruit wall.

1 General characters:
Plant body is a diploid sporophyte and is well differentiated into underground root system ami aerial shoot system.

• Plants produce special sexual reproductive structures called flowers.
• Flowers contain a male reproductive organ androecium and a female reproductive organ gynoceium.
• Androecium is composed of stamens which produces pollengrains. Gynoecium is composed of carpels which contain ovules.
• Pollengrain represents the male gametophyte and produce male gametes. Embryo sac in the ovule represents the female gametophyte and bears female gamete eggs and secondary nucleus.
• Fertilisation is a double fertilisation where two male gametes involve in the process, one unit with the egg and other with the secondary nucleus of female gametophyte.
• After fertilisation fertilised egg develops into embryo. Ovule develops into seed which is enclosed in the fruit structure developed from the ovary. Seed on germination, gives rise to sporophyte. .
• Life cycle shows distinct heteromorphic alternation of generation between independent predominant diploid sporophytic phase and dependent reduced haploid gametophytic phase.

The division Angiospermae is divided into two classes :
(i) Monocotyledonae and
(ii) Dicotyledonae, based on the number of cotyledons in their seeds.

The major differences between the two classes are listed below.
Monocotyledonae:-
(i) Plants have a fibrous root system.
(ii) Leaves have a sheathing leaf base.
(iii) Leaves show parallel venation.
(iv) Flowers are trimerous.
(v) Seeds have only one cotyledon.

Dicotyledonae:-
(i) Plants have a tap root system.
(ii) Leaves have a petiole.
(iii) Leaves show reticulate venation.
(iv) Flowers are pentamerous and rarely tetramerous.
(v) Seeds have two cotyledons;

• Vascular tissue are well-developed xylem has vessels and phloem has sieve tubes.
• A flower is a shoot modified for reproduction.
• The male sex organs in a flower are the stamens or microsporophylls.
• Each stamen consists of a filament and an anther.

Anther encloses microsporangia, where the microspore mother cells undergo meiosis to form microspores, microspores develop into pollengrains.
• The female reproductive organ of a flower is a pistil /carpel.
A pistil has three parts :
(i) an ovaiy, that encloses ovule.
(ii) a style, that exposes the stigma and
(iii) a stigma, to receive the pollengrains.

Each ovule (megasporangium) has a body called nucellus, covered ova- by two integuments except at the micropyle. A megaspore mother cell is differentiated in the nucellus and it undergoes meiosis to form a linear tetrad of megaspores.

Three out of these megaspones degenerate and the functional megaspore enlarges and forms the embryo sac (female gametophyte).

It has three cells at the micropylar end, forming the egg apparatus (consisting of one female gamete and two synergids), three cells at the chalazal end termed as the antipodal cells and two cells at the centre called polar nuclei, which fuse to form a diploid secondary nucleus.

Pollengrains are brought to the surface of stigma of the pistil during pollination.

Each pollen grain germinates forming a pollen tube that carries two male gametes (siphonogamy), to the embryosac, growing through the tissues of stigma and style.
One of the male gametes fuses with the female gamete to form the zygote, this fusion is called syngamy.

The second male gamete fuses with the secondary nucleus to form the triploid primary endosperm nucleus. This fusion is called triple fusion.

Since there are two fusions in the embryo sac during fertilisation, the phenomenon is called double-fertilisation and it is unique to angiosperms.

After fertilisation, the antipodal cells and synergids degenerate, while the embryo and endosperm start their development.

The ovule forms the seed and the ovary becomes the fruit.
The seed on germination gives rise to the plant, the dominant phase in the life cycle.

Life Cycle Patterns:

• Three basic types of life cycles are exhibited by different groups of plants.
• The gametophytic phase is haploid and forms gametes by mitosis.
• A diploid zygote is formed by the fusion of two such haploid gametes.
• Zygote is the first cell of the diploid/sporophytic phase.
• The zygote divides by mitosis to form the sporophyte or it may undergo meiosis to give rise to the gametophyte.
• When a sporophyte is developed , it forms spores by meiosis in the spore mother cells.
• The spore is the first cell of gametophyte and develops into the gametophyte.
• Thus there is alternation between the gamophytic / haploid phase and the sporophytic/ diploid phase.

A. Haplontic life cycle:

• The dominant phase in the life cycle is a free-living gametophyte (haploid).
• The diploid phase is represented only by the single-celled zygote.
• The zygote undergoes meiosis (zygotic meiosis) and forms haploid spores which germinate to form the gametophyte. e.g Spirogyra, Chlamydomonas etc.

B. Diplontic life cycle:

C. Haplo-diplontic life cycle:

• It is an intermediate type of life cycle where both the sporophyte and gametophyte are multicellular and equally dominant.
• In bryophytes, the dominant phase is the gametophyte and the sporophyte is dependant on the gametophyte.
• In pteridophytes. the dominant phase is the sporophyte and the gametophyte is free living plant body.

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