Biology XI Notes
The Kingdom Plantae - Short Questions Answers
Chapter # 09
Short Questions Answers
Section III - Biodiversity
THE KINGDOM PLANTAE
Q.1: Write a note on classification of Plants?
Ans: Classification of Plants:
Kingdom plantae is classified into two divisions:
- Division – Bryophyta (Non vascular plants)
- Division – Tracheophyta (Vascular plants)
Division Bryophyta: (Non-Vascular Plants)
This division is divided into three classes:
- Class – Hepaticae (Liverworts)
- Class – Musci (Mosses)
- Class – Anthocerotae (Hornworts)
Division Tracheophyta: (Vascular Plants)
This division is divided into five sub-divisions:
- Sub-division - Psilopsida (Psilopsids)
- Sub-division - Lycopsida (Club Mosses)
- Sub-division - Sphenopsida (Horse tail)
- Sub-division - Pteropsida (Ferns)
- Sub-division - Spermosida (Seed plants)
Q.2: What are the Characters of Bryophyta?
Ans: Characteristics of Bryophyta:
These plants include liverworts hornworts and mosses.
- These plants are found in humid and shady places. They are land-inhabiting plants. They are non-flowering plants.
- Bryophytes are autotrophs i.e. they contain chlorophyll and can manufacture their own food material.
- They are small plants. Their body is thallus like or the body is divided into stem and leaves.
- True root is absent in Bryophytes, but hair-like structures arise from the lower part of the plant, called rhizoids. They help in the attachment of plant body to the soil and as well as in the absorption of water.
- In their life cycle heteromorphic alternation of generations is present.
- Their main body is gametophyte, which is the first stage of their life cycle.
- They do not possess vascular tissues.
- Division Bryophyta is divided into three classes:
- Class – Musci (Mosses)
Q.3: Describe the Life Cycle of Bryophyta (Funaria)?
Ans: LIFE CYCLE OF BRYOPHYTA (FUNARIA HYGROMETRICA):
Moss (Funaria) is a small plant, grows on moist places. The life cycle shows heteromorphic alternation of generations. The life cycle is completed into two stages:
Gametophytic Stage:
It is the first and dominant phase of life cycle. In this phase male and female reproductive organs are produced, antheridia (male) and archegonia (female).
The Antheridia:
The antheridia are club-shaped. Inside the antheridium motile biflagellate antherozoids (male gametes) are produced.The Archegonia:
Each archegonium is flask-shaped. It consists of stalk, venter and neck. The stalk helps in the attachment of archegonium. Venter is the middle swollen part. It contains a large egg cell and a smaller venter canal cell. Neck is the upper elongated tube-like part. It contains neck-canal cells.Fertilization:
The motile antherozoids move towards the archegonium in the presence of water. They enter the archegonium through its open mouth and one spermatozoid fuses with egg cell, with the result the zygote (2n) is formed.
Sporophytic Stage:
The zygote develops into sporophyte. The sporophyte grows upon gametophyte, it depends partially or completely for its nourishment upon the tissues of gametophyte.
The sporophyte consists of three parts, foot, seta and capsule. Foot helps in the attachment of sporophyte and in the absorption of food from the tissues of gametophyte. The seta is the stalk of capsule. The capsule produces spore-mother cells. They are diploid (2n). They divide by meiosis and form haploid (n) spores. Each spore can germinate into a new gametophyte during favorable conditions.
Q.4: Write a note on plants become adapted to land?
Ans: PLANTS BECOME ADAPTED TO LAND:
It is the opinion of all biologists that the land plants and animals have been evolved from aquatic living organisms. On land they got their control after a difficult and long period.
The life of aquatic living organisms is easy, because water is essential for all processes of life. The aquatic organisms do not face dry conditions. The carbon compounds are abundant in the sea which are used in photosynthesis. The plant releases oxygen during photosynthesis which is utilized by animals. The temperature of sea-water does not charge very rapidly like dry land. In this way the life of aquatic living organism’s remains continue in a normal way.
When the plants migrated on land, they faced certain problems. The most important ones are as follows:
- To obtain and conserve water.
- To absorb CO₂ from the atmosphere for photosynthesis.
To solve these problems, the plants changed their body structure according to the environment. First of all, they shifted from aquatic to the amphibious habitat, then they started their life on dry land. Amphibians are the plants which grow on moist places or live both in dry and wet habitats. For example, Mosses and Liverworts.
The characteristics of plants which are migrated from wet to dry conditions are as follows:
- Production of rhizoids for water absorption.
- Conservation of water.
- Absorption of CO₂.
- Heterogamy (Formation of different gametes, male and female).
- Protection of reproductive cells.
- Formation of embryo.
Q.5: What are Tracheophytes? Name the groups of Tracheophytes?
Ans: Tracheophyta division consists of vascular plants. They are terrestrial in nature. This division is divided into five sub-divisions.
- Sub-division - Psilopsida (Psilopsids)
- Sub-division - Lycopsida (Club mosses)
- Sub-division - Sphenopsida (Horse tail)
- Sub-division - Pteropsida (Ferns)
- Sub-division - Spermospsida (Seed plants)
The plants of this division have four fundamental adaptations for terrestrial habitat. These are as follows:
- Around the reproductive organs, a protective layer of sterile jacket cells is present.
- Multi-cellular embryos remain in the female reproductive organs, archegonia.
- On the aerial parts of the plant, cuticle layer is present.
- Xylem is present for conduction of water.
Q.6: Write a note on Evolution of Leaf?
Ans: EVOLUTION OF LEAF: Leaf is a very important organ of plant because it takes part in photosynthesis. They are evolved from the primitive vascular plants. To trace the origin of leaf we have to study the types of leaves. In vascular plants there are two types of leaves.
- One is simple, small, and scale-like. It contains only one vein, so it is called a single-veined leaf.
- Another type is a multi-veined leaf because it contains many veins. It is larger in size with distinct lamina.
Origin Of Single-Veined Leaf: In the case of single-veined leaves, the fossils provide no proper evidence. It is assumed that it originated from a leaf-less branch of primitive vascular plants by the reduction in size and gradually this leaf-less branch has changed into a single-veined leaf. This type of leaf was developed in club-moss and horse-tail plants.
Origin Of Many-Veined Leaf: In the case of many-veined leaves, it is assumed that their production started much later. These are the modified form of forked-branches in primitive land plants. In their evolution, the first step was the union of forked-branches and continuation of growth in one direction, so they were changed into a flat body. The second step was the formation of green cells between these branches and vascular tissues.
They were filled up by photosynthetic tissues, and they were ultimately changed into leaf-like structures.
Q.7: Describe the structure and reproduction of Rhynia?
Ans: Rhynia is the most primitive known plant. It was lived about 40 million years ago and now it is preserved as a fossil.
The plant body of Rhynia consisted of two parts, an underground rhizome and an aerial stem. The aerial stem was 20-50 centimeters in height and 1-6 millimeters in diameter.
The rhizome was creeping and dichotomously branched. From its lower side rhizoids were produced which were to absorb water and salts from the soil. True roots were absent. The aerial stem was erect and dichotomously branched. The branches were green due to the presence of chlorophyll; they had the function of photosynthesis. The branches were leafless.
Internal Structure Of Rhynia: The internal structure of the branches of Rhynia shows the following parts:
- Epidermis: It is the outermost layer having stomata.
- Cortex: Below the epidermis, the cortex region is present.
- Vascular Tissues: These are present in the center, surrounded by the cortex. Xylem is in the center, which is surrounded by phloem.
Reproduction: Rhynia plant was a sporophyte. From the branches of the aerial stem, sporangia were produced. They were oval-shaped or cylindrical. They produced spores. The spores were responsible for developing into a gametophyte of Rhynia, but it could not be preserved; thus, its details are still unknown.
Q.8: Describe the Sporophytic Stage in the life cycle of Selaginella (Lycopsida)?
Ans: Sporophytic Stage Of Selaginella: In this stage, the plant reproduces by the asexual method. Selaginella plant is heterosporous, i.e., it produces two types of spores, microspores, and megaspores.
At the time of reproduction are developed cone-like bodies at the apex of fertile shoot, called strobili. In the strobili, the leaf-like structures are called sporophylls. These sporophylls are of two types: microsporophyll’s and megasporophylls. A single strobilus bears microsporophyll’s at the upper side and megasporophylls at the lower side. In the axil of microsporophyll’s microsporangia and in the axil of megasporophylls megasporangia are developed.
In each microsporangium many microspores are produced. The microspores are changed into male gametophyte.
In each megasporangium, four megaspores are produced, which develop into female gametophyte.
Q.9: Describe the Gametophytic Stage in the life cycle of Selaginella (Lycopsida)?
Ans: Gametophytic Stage: In Selaginella, two types of gametophytes are present. The male gametophyte and female gametophyte. In male gametophyte, male gametes are produced. In female gametophyte, small flask-shaped archegonia are developed. In each archegonium, an egg cell (female gamete) is present.
Fertilization: The male gametes enter the archegonia, each male gamete fuses with the egg cell and forms oospore (zygote). The oospore produces an embryo, which develops into a new Selaginella plant.
Q.10: Write a note on Evolution of Seed?
Ans: There is evolution of seed in plants. In Selaginella, two types of spores are produced, microspores, smaller in size, and megaspores, larger in size. This process is called heterospory. The microspores develop into male gametophytes, and megaspores develop into female gametophyte.
The sporangia in Selaginella are of two kinds. These sporangia are protected by scale-like structures. Similarly, the sporangia of club mosses, horsetails, and ferns are also protected. This is the process of evolution. In Carboniferous era, some fern-like plants were produced, and their sporangia were surrounded by some special branch-like structures. During evolution, branch-like structures were modified into an envelope or integument around the sporangia.
In seed plants, there is a different condition. Unlike other green plants, in the seed plants, the megaspores remain inside the sporangia, which are covered by protective covering called integuments. The megaspores develop into female gametophyte. This gametophyte is protected by integuments.
There are three steps in the evolution of seeds:
- Origin of Heterospory i.e., Formation of two types of spores
- Development of integument for the protection of megasporangia
- Retention of the mature megaspores in the sporangia to develop female gametophyte
Q.11: Write down the important characters of Pteropsida (Ferns)?
Ans: Important Characters of Pteropsida (Ferns): The important characters of these plants are as follows:
- The plant body consists of roots, stem, and leaves. It is sporophytic in nature.
- The leaves are larger in size, called megaphylls or fronds.
- The stem is subterranean rhizome, but in some ferns, it is aerial and erect.
- Each leaf consists of two parts, petiole and blade. The petiole is covered with hairs, called ramenta.
- The blade is either simple e.g., Ophioglossum or pinnately compound i.e., divided into many small leaflets, called pinnae and pinnules.
Q.12: Describe briefly the life cycle of Fern?
Ans: The life cycle of Fern is completed in two stages:
- Sporophytic stage
- Gametophytic stage
It shows alternation of generations.
Sporophytic Stage: It is an asexual stage. In this stage, the mature leaves (sporophylls) produce small reddish brown bodies, called Sori. Sori are the group of sporangia.
Each sporangium consists of two parts, a stalk, called sporangiophore, and a capsule. Capsule is biconvex oval shaped structure. The wall of capsule has two parts, a thin-walled part, called stomium, and a thick-walled part, known as annulus.
The sporangium spore mother cells are produced, which divide by meiosis and produce haploid spores. When spores are mature, the sporangial wall ruptures at stomium and spores are liberated out. Each spore germinates and develops into gametophyte, which is also called Prothallus.
Gametophytic Stage: The spore germinates into a heart-shaped body, called prothallus. It is the gametophyte.
The prothallus is a gametophyte. It produces two different types of reproductive organs, male and female. The male organs are called antheridia, which are developed towards the rhizoid sand, and female organs are known as archegonia, which are borne in the central region of the prothallus.
Each antheridium produces male gametes. The archegonia are flask-shaped. Each archegonium produces an egg cell (female gamete).
Fertilization: At the time of fertilization, many male gametes move towards archegonia. Many male gametes enter the archegonium, but one fuses to form oospore.
The oospore germinates into a young sporophyte, which grows into a new fern plant.
Q.13: Describe the staminate cone of Pinus?
Ans: STAMINATE CONE: (MALE CONE)
- It is a small cone. Its size is less than 3cm.
- Each cone consists of a central axis. From i
- ts both sides spiral-shaped scales are developed, called microsporophylls.
- On the inner side of each scale, two microsporangia are present.
- In each microsporangium, numerous microspores are produced by meiosis.
- Each microspore consists of two layers; the outer layer is called exine, and the inner one is known as intine.
Q.14: Describe the ovulate cone of Pinus?
Ans: OVULATE CONE: (FEMALE CONE)
- It consists of a central axis. Round the axis many thin, brownish scales are produced, which are arranged in spiral manner. They are called carpellary scales or bract scales.
- At the upper side of each carpellary scale a large, hard, and woody scale is present, known as ovuliferous scale. It produces two ovules on the inner side.
- Each ovule consists of a central body, called nucleus or megasporangium. In the nucleus or megasporangium, a megaspore is present. Megaspore takes part in the formation of female gametophyte.
Q.15: Write the different parts of Flower?
Ans: FLORAL ORGANS: A flower consists of four types of floral organs. These parts are arranged in whorls in a definite order. These organs are as follows:
Calyx:
- This is the first and outermost whorl, composed of small, leafy structures, called sepals. They are usually green, but sometimes they are highly colored, called petaloid. Their function is to protect the inner parts of the flower. When the sepals are free, it is called polysepalous, and when they are united together, it is termed as gamosepalous. Sometimes the sepals are modified into hairs and called pappus, e.g., Composite family.
Corolla:
- This is the second whorl and is composed of expanded and brightly colored structures, called petals. They may also have glands which produce juicy substances. They attract the insects for pollination.
If the petals are free, it is called poly-petalous, and if petals are fused together, it is known as gamo-petalous. In some flowers sepals and petals do not differ in shape and colour and their members are alike to form a single part of a flower; it is termed as perianth.
Androecium:
- It is composed of the male reproductive organs, the stamens. Each stamen consists of three parts: filament, anther, and connective.
- Filament is the stalk, and anther is the expanded head borne at the tip. Each anther has two lobes, and each lobe produces two chambers called pollen sacs. Within each pollen sac, the pollen grains are present, which are the male reproductive bodies.
Gynoecium:
- It is the female whorl of the flower and is composed of Carpels.
Apocarpous Or Syncarpous:
- When many carpels are present in a pistil and they are free, it is termed as apocarpous, and when the carpels unite together, it is known as syncarpous.
Parts Of A Pistil:
- Each pistil consists of three parts: stigma, style, and ovary. Stigma is the uppermost part, which receives the pollen grains, style is the middle elongated stalk, and ovary is the basal swollen part.
- The ovary has one or more chambers inside. Each chamber contains one to many ovules. The ovary having one chamber is called unilocular, and when many chambers are present, it is known as multilocular. The ovules are attached to the wall of the ovary by small structures called placenta.
Q.16: What is Placentation?
Ans: PLACENTATION:
- Ovules are attached to the inner wall of ovary by special tissues, called placenta. The ovule is attached to the placenta by a short stalk, the funiculus. The arrangement of placenta within the ovary is known as placentation. There are several types of placentation: basal, marginal, central, axile, parietal.
Q.17: Describe the structure of ovule?
Ans: STRUCTURE OF OVULE:
- The ovule is enclosed in two outer coats, called integuments. At one end of the ovule, a small pore is present, the micropyle. Within the integuments, nucleus is present. It is considered as megasporangium. It contains egg sac or embryo sac. At the micropylar end, three cells are present; one of these cells is the egg cell or ovum, and other two cells are called synergids. At the...
Q.18: Describe the Floral Characters of Family Rosaceae?
Ans: FLORAL CHARACTERS:
Inflorescence:
- Solitary, racemose or cymose.
Flower:
- Pedicellate, complete, bisexual, actinomorphic, hypogynous or perigynous, usually showy and scented, pentamerous.
Calyx:
- Sepals 5, gamosepalous (fused) or polysepalous (free), aestivation valvate. Calyx tube is present.
Corolla:
- Petals 5 or numerous in multiple of five, polypetalous, imbricate aestivation, rosaceous, large, showy of various colours.
Androecium:
- Stamens numerous, polyandrous, usually borne in many cycles of 5, anthers small, bilocular.
Gynoecium:
- Carpels 1-5 or many, apocarpous or united, enclosed in calyx tube, superior ovary, sometimes inferior ovary, one or two ovules in each carpel. Style short, stigma linear, capitate.
Placentation:
- Basal in apocarpous or monocarpellary flower, Axile in syncarpous or multicarpellary flower.
Fruit:
- Pome or drupe, or achene follicle.
Seed:
- Non-endospermic.
Floral Formula:
- ⊕, ⊍, K₅, C₅-∞, A∞, G₁-5 or ∞ or G₅
Q.19: Describe the economic importance of Family Rosaceae?
Ans: ECONOMIC IMPORTANCE OF FAMILY ROSACEAE:
Some plants produce edible fruits, such as:
- Apple (Pyrus malus), Apple
- Pear (Pyrus communis), Naspati
- Peach (Prunus persica), Aru
- Almond (Prunus amygdalus), Badam
- Apricot (Prunus arminiaca), Khubani
- Strawberry (Fragaria)
- Rose (Rosa indica), Gulab
Many plants are grown for ornamental purposes, e.g. Rose (Rosa indica), Spiraecea, Sorbus, Potentilla etc.
Scents are obtained from Rose and other plants.
The petals of Rose are used to manufacture a laxative, called gulkand.
The branches of some trees are used as walking sticks.
The extract of Rose (Ark-Gulab) is used in eye diseases and for other purposes.
The wood of Pear (Pyrus pestia) is used to make tobacco pipes.
Q.20: Describe the Floral Characters of Family Solanaceae?
Ans: FLORAL CHARACTERS:
Inflorescence:
An axillary cyme.Flower:
Pedicellate, bisexual, actinomorphic, hypogynous, pentamerous, bracteate or ebracteate.Calyx:
5 sepals, gamosepalous, aestivation valvate, persistent, hairy, campanulate (bell-shaped), green.Corolla:
5 petals, gamopetalous, aestivation valvate, rotate tubular, infundibuliform (funnel-shaped) or tubular.Androecium:
5 stamens, polyandrous, epipetalous (attached with petals), alternate with corolla lobes. Usually of unequal size.Gynoecium:
Bicarpellary; syncarpous, pistil one, ovary obliquely placed, usually 2-chambered, becoming two or many-chambered by false septa, many ovules, Placentation - axile.Fruit:
Capsule (Datura), Berry (Solanum nigrum)Formula:
⊕, ⊍, K5, C5, A5, G2
Q.21: Describe the economic importance of Family Solanaceae?
Ans:
The economic importance of the family Solanaceae is as follows:
- Some plants of the family are used as vegetables. e.g. Potato (Solanum tuberosum), Tomato (Lycopersicum esculentum), Brinjal (S. melongena).
- Some plants are of medicinal value, such as the roots of Solanum xanthocarpum are used in cough, asthma. The leaves of Datura metal are used in the treatment of asthma.
- Tobacco (Nicotiana tabacum) is narcotic in nature. It is a source of nicotine.
- Red pepper or chilli is used as Condiment.
- Some plants are used for Ornamental purposes e.g. Petunia, Queen of night (Jassamine) is grown in the gardens, its flowers are scented at night.
Some Important Plants:
- Solanum tuberosum (Potato)
- Solanum melongena (Brinjal)
Q.22: Describe the important Floral Characters of Family Mimosaceae?
Ans: FLORAL CHARACTERS:
Inflorescence:
Racemose raceme.Flower:
Pedicellate or sessile, bracteate, complete, bisexual, actinomorphic, hypogynous.Calyx:
Usually 5 sepals, gamosepalous, rarely polysepalous, valvate aestivation, in some plants aestivation is imbricate, green.Corolla:
- 5 petals, gamopetalous, rarely polypetalous, valvate aestivation, corolla lobed.
Androecium:
- 5 to numerous, polyandrous, united at the base.
Gynoecium:
- Monocarpellary, ovary superior, unilocular, many ovules, style long, Placentation - Marginal.
Fruit:
- Legume or Lomentum.
Q.23: What is the economic importance of Family Mimosaceae?
Ans: ECONOMIC IMPORTANCE OF FAMILY MIMOSACEAE:
- Many trees provide wood for fuel or furniture, e.g. Acacia, Xylia, and Albizzia.
- Some plants yield gum, e.g., Acacia senegal and Acacia nilotica.
- A dye called Katha is obtained from Acacia catechu.
- The leaves of Acacia nilotica are used as a blood purifier.
- Some plants are of ornamental value, e.g., Mimosa pudica, Acacia melanoxylon.
Important Plants:
- Acacia arabica (Babool)
- Acacia catechu (Katha)
- Mimosa pudica (Touch-me-not)
- Albizzia lebbek (Sins - Timber plant)
- Acacia nilotica (Gum tree, Kikar)
- Prosopis glandulosa (Prosopis)
Q.24: What are the Floral Characters of Family Caesalpiniaceae?
Ans: FLORAL CHARACTERS:
- Inflorescence: Racemose raceme or spike.
- Flower: Pedicellate, bracteate, complete, bisexual, zygomorphic, rarely actinomorphic, perigynous or hypogynous, pentamerous.
- Calyx: 5 sepals, polysepalous or gamosepalous imbricate or valvate.
- Corolla: 5 petals, polypetalous, imbricate, with the lower petal being the innermost.
- Androecium: Few or 10 stamens, polyandrous; filaments are of unequal size, sometimes staminodes (small stamens) are present.
- Gynoecium: Monocarpellary, ovary superior, unilocular, ovules 1–many along the margin, placentation - marginal.
Q.25: What is the economic importance of Family Caesalpiniaceae?
Ans: ECONOMIC IMPORTANCE OF FAMILY CAESALPINIACEAE:
- Some plants are used as food, such as the leaves and buds of Bauhinia variegata (Kachnar) are used as vegetables.
- The leaves of Tamarindus indica contain tartaric acid. These are edible.
- The leaves of Cassia alata are used in skin diseases and for the cure of ringworm.
- Cassia senna yields a drug, senna. It is used in laxative medicines.
- Oil from the seeds of Cymonera is used for skin diseases.
- Some plants are cultivated for ornamental purposes, e.g. Bauhinia variegata (Kachnar); Cassia fistula (Amaltas); Parkinsonia sp.
- A dye haematoxylon is obtained from Haematoxylon species.
- Cassia fistula (Amaltas)
- Bauhinia variegata (Kachnar)
- Parkinsonia sp. (Vilayati Kikar)
- Tamarindus indica (Tamarind - Imli)
- Haematoxylon sp.
- Poinciana regia (Flame of Forest - Gul-e-Mohar)
Important Plants Of The Family:
Q.26: Describe the Floral Characters of Family Fabaceae?
Ans: FLORAL CHARACTERS:
- Inflorescence: Mostly racemose or solitary axillary.
- Flower: Pedicellate, complete, bisexual, zygomorphic, perigynous or hypogynous, pentamerous.
- Calyx: 5 sepals, gamosepalous, valvate aestivation, green, hairy.
- Corolla: 5 petals, polypetalous, petals are of different sizes. The lowest petal is the largest one, called vexillum or standard; two side petals are wings or allae, and the two innermost petals fuse together to form a boat-shaped structure, known as keel or carina. This arrangement is called vexillary; it is called papilionaceous flower.
- Androecium: 10 stamens, diadelphous (found in two groups), nine stamens are united, and one is free (9) + 1.
- Gynoecium: Monocarpellary (one carpel), ovary superior, consists of one chamber (unilocular), many ovules are present along the margin.
- Placentation: Marginal
- Fruit: Legume
- Seed: Non-endospermic.
Floral Formula:
†, K_5, G_(1+2+(2)), A_(9)+1, G_1
Q.27: What is the economic importance of Family Fabaceae?
Ans: ECONOMIC IMPORTANCE:
- Some plants of this family are used as food material, such as Pea, Gram, Bean, Pulses, Groundnut, etc.
- From groundnut oil is obtained, which is used to manufacture banaspati ghee.
- Some plants are used as vegetables, e.g., soybean, pea.
- Some plants are used by animals as their food.
- From some plants, dyes are obtained, such as Indigofera (Neel).
- Some plants are of ornamental value, e.g., Clitoria.
- From Sisso tree, wood is obtained, which is used to make furniture.
Important Plants Of The Family:
- Pisum sativum (Pea)
- Lathyrus odoratus (Sweet pea)
Q.28: Describe the Floral Characters of Family Poaceae?
Ans: FLORAL CHARACTERS OF THE FAMILY:
Inflorescence:
Spike or spikelet. In spikelet, two bracts are present at the lower side, the outer or lower bract is called first glume, and the upper or inner bract is known as the second glume. Each small flower also has two bracts; the outer bract is lemma, and the inner bract is called palea (The lemma is also called superior palea, and the other one is known as inferior palea).Flower:
Sessile, bisexual, zygomorphic, hypogynous. Lemma and palea form the protective covering around the flower.Perianth:
It consists of two lodicules, free, valvate.Androecium:
Stamens 3, polyandrous (free), long filaments.Gynoecium:
Carpels 3 but only one functional, ovary superior, unilocular (one-chamber), one basal ovule placentation - Basal, style two, stigma feathery.
Floral Formula:
†, P₂ lodicules, A₃, G₃ or G₁
Q.29: What is the economic Importance of Family Poaceae?
Ans: ECONOMIC IMPORTANCE OF THE FAMILY:
- Many plants of this family are used as food material, such as Maize, Rice, Wheat, Oat, etc.
- Some plants are used by animals as their food.
- Bamboo and other plants are used as building material.
- From sugarcane, sugar is prepared.
- From Bamboo and other plants, paper is manufactured.
- From some grasses, oils and medicines are obtained.
Q.30: Distinguish between:
Ans: SEXUAL & ASEXUAL REPRODUCTION:
| Sexual reproduction | Asexual reproduction |
|---|---|
| In sexual reproduction, formation of two different kinds of reproductive bodies are produced, male gametes and female gametes. | In asexual reproduction, usually the same type of bodies are formed, called Spores. (In rare cases, spores may be of two types). |
| The male and female gametes fuse together; this process is called fertilization. | There is no fertilization process. |
| By the fusion of gametes, a zygote is formed. | There is no formation of zygote. |
Important Plants Of The Family:
- Triticum (Wheat)
- Zea-mays (Maize)
- Oryza Sativa (Rice)
- Saccharum Officinarum (Sugar-cane)
- Bambusa (Bamboo)
ISOMORPHIC & HETEROMORPHIC ALTERNATION OF GENERATION:
| Isomorphic Alternation Of Generation | Heteromorphic Alternation Of Generation |
|---|---|
| In some plants, the life cycle is completed in two stages, sporophytic stage (asexual stage) and gametophytic stage (sexual stage). Both plants of two stages are similar in morphology; it is called isomorphic alternation of generations. | In some plants, the life cycle is also completed in two stages, sporophytic stage and gametophytic stage, but the plants of two stages are different in morphology; it is known as heteromorphic alternation of generations. |
| E.g., Ulva, Dictyota. | E.g., Marchantia Sunflower. |
SPOROPHYTE & GAMETOPHYTE:
| Sporophyte | Gametophyte |
|---|---|
| Sporophyte is the plant which shows asexual stage. | Gametophyte is the plant which shows sexual stage. |
| It produces spores, which may be similar or, in few cases, of different types. | It produces gametes, which are of two types, male and female. |
| There is no fusion of spores; each spore directly develops into a new plant or gametophytic stage. | The male and female gametes fuse together to form zygote. The zygote develops into a new plant or sporophytic stage. |
XYLEM & PHLOEM:
| Xylem | Phloem |
|---|---|
| It is a complex tissue which helps in the conduction of water from roots to the upper. | Phloem is also a complex tissue which helps in the translocation of food from one part to another part in the body of plants. |
| The flow of water in xylem occurs only in one direction i.e., from roots to the upper region, up to the leaves. | The flow of food in the xylem occurs in both directions i.e., from the upper region to the lower region or from lower to upper region. |
| Xylem consists of four different types of tissues: | Phloem consists of four different types of tissues: |
| - Tracheids | - Sieve tubes |
| - Vessels or Tracheae | - Companion cells |
| - Wood parenchyma | - Phloem parenchyma, bast parenchyma. |
| - Wood fibers | - Phloem fibres or bast fibres. |
MALE (STAMINATE) & FEMALE (OVULATE) CONE OF PINUS:
| Male cone of pinus (Staminate cone) | Female cone of pinus (Ovulate cone) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| It is a small cone. Its size is less than 3 cm. | It is a large cone. Its size is more than 3cm. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Each cone consists of a central axis. | It also consists of a central axis. From its sides, scales arise, which are of two types: | ||||||||||||||||||||||||||||||||||||||||||||||||||||
VESSELS & SIEVE TUBES:
GYNOECIUM OF ROSACEAE & GYNOECIUM OF SOLANACEAE:
ALGAE & PLANTS:
BRYOPHYTA & TRACHEOPHYTA:
| - Thin brownish scales, the carpellary scales or bract scales. |
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