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Karnataka 1st PUC Biology Question Bank Chapter 5 Morphology of Flowering Plants
1st PUC Biology Plant Kingdom NCERT Text Book Questions and Answers
What is meant by modification of root?
When roots are modified to carry out some additional functions like storage of food, additional mechanical support, other than the absorption of water, minerals and main support to plant then, they represent a modification of roots.
What type? of modification of root is found in the:
(a) Banyan tree
(c) Mangrove trees
(a) In banyan tree, adventitious roots are modified into hanging supporting roots for a giant banyan tree. These roots develop from branches and provides additional support to reach down the ground. Hence this modification is prop root.
(b) Taproots of turnip get swollen and modified for storage of food. Such roots are called napiform roots.
(c) In mangrove tree, roots come out from the ground and grow vertically. Such roots are called pneumatophores or respiratory roots. They help to get oxygen for respiration, to get modified into pneumatic structures. Mangrove trees generally grow in a marshy areas.
Justify the following statements on the basis of external features:
1. Underground parts of a plant are not always roots.
2. Flower is a modified shoot.
1. Underground parts of a plant are not always roots as some perennial herbs develop their stems underground for the purpose of perennation, and food storage during unfavourable conditions. The stem produces aerial branches every year when conditions become favourable. The underground stems act as storage organs and also help in vegetative propagation by means of their buds. These stems are non-green and leafless like roots but differ from them on the basis of:
- presence of nodes and internodes, scale-leaves, and axillary and terminals buds
- absence of root hair and root cap.
2. Flower is highly modified and condensed
shoot meant essentially for the sexual reproduction of the plant. Calyx, corolla, androecium and gynoecium are modifications of leaf for playing a various role in reproduction.
How is a pinnately compound leaf different from a palmately compound leaf?
Phyllotaxy is the pattern of arrangement of leaves at the stem or branch. This is usually of three types :
- Alternate: In this arrangement, a single leaf arises at each node in an alternate manner. e.g., in china rose, mustard & sunflower plants.
- Opposite: A pair of leaves arise on each node in the manner that these lie opposite to each other, e.g. guava leaves.
- Whorl: In this arrangement, more than two leaves arise at the node and form a whorl. e.g., in Alstonia, Nerium (Oleander).
Explain with suitable examples the different types of phyllotaxy.
Phyllotaxy is the pattern of arrangement of leaves on the stem or branch. This is usually of three types alternate, opposite, whorled. In the alternate type of phyllotaxy, a single leaf arises at each node in m alternate manner, as in china rose, mustard, and sunflower plants. In opposite types, a pair of leaves arise at each node and lie opposite to each other as in holotropic, Guava plants. If more than two leaves arise at a node and form a whorl, it is called whorled, as Nerium, Alstonia.
Define the following terms:
- superior ovary
- perigynous flower
- epipetalous stamen
- Aestivation: It is the arrangement of sepals/ petals in relation to one another in floral buds. It is of four types open, valvate, twisted, and imbricate.
- Placentation: The manner of arrangement of placentae inside the cavity of the ovary for providing cushions is called placentation.
- Actinomorphic: A flower that can be vertically divided into two equal halves by any vertical division passing through a centre is actinomorphic. Such flowers are radially symmetrical, e.g., Mustard.
- Zygomorphic: A flower that can be vertically divided into two equal halves in one vertical plane only. Such flowers are bilaterally symmetrical, e.g., Pea, Salvia.
- Superior ovary: When the flower is hypogynous, it has an ovary attached to the receptacle above the attachments of floral parts, ex.- berries, drupes etc.
- Perigynous: When the sepals, petals, and stamens appear to be arising from the middle of the ovary, the flower is described as perigynous. In these flowers, the ovary is semi-inferior, e.g., Saxifraga.
- Epipetalous stamen: Stamen are attached with petals.
(a) Racemose and cymose Inflorescence
(b) Fibrous root and adventitious root
(c) Apocarpous and syncarpous ovary
(a) Racemose and cymose inflorescence:
In the racemose type of inflorescence, the main axis continues to grow, the flowers are borne laterally in acropetal succession. Acropetal succession means that older flowers are at the base and younger flowers are near the apex. In the cymose type of inflorescence the main axis terminates in a flower, hence is limited in growth. The flowers are borne in a basipetal order. In basipetal succession older flowers are at the apex and younger flowers are near the base.
(b) Fibrous root and adventitious root:
In monocotyledonous plants, the primary root is short-lived and is replaced by a large number of roots. These roots originate from the base of the stem and constitute the fibrous root system, as seen in the wheat plant. In some plants, like grass, monster, and the banyan tree, roots arise from parts of the plant other than the radicle and are called adventitious roots.
(c) Apocarpous and syncarpous ovary:
When more than one carpel is present, they may be free as in lotus and rose and are called apocarpous. When carpels are fused as in mustard and tomato, they are termed syncarpous.
Draw the labelled diagram of the following:
(i) gram seed
(ii) V.S. of maize seed
Describe modifications of the stem with suitable examples.
Modifications of Stem
Food Storage: Stems are modified to perform different functions. Underground stems of potato, ginger, turmeric, Colocasia are modified to store food in them. They also act as organs of perennation to tide over conditions unfavourable for growth.
Tendrils Stem: Tendrils which develop from axillary buds, are slender and spirally coiled and help plants to climb, such as in gourds (cucumber, pumpkins, watermelon) and grapevines.
Thorns: Axillary buds of stems may also get modified into woody, straight and pointed thorns.
Thoms are found in many plants such as Citrus, Bougainvillea. They protect plants from grazing animals.
Some plants of arid regions modify their stems into flattened (Opuntia), or fleshy cylindrical (Euphorbia) structures.
They contain chlorophyll and carry out photosynthesis. Vegetative
Reproduction: Underground stems of some plants such as grass and strawberry, etc., spread to new niches and when older parts die, new plants are formed.
In plants, like mint and jasmine, a slender lateral branch arises from the base of the main axis and after growing aerially for some time arch downwards to touch the ground.
A lateral branch with short internodes and each node bearing a rosette of leaves and a tuft of roots are found in aquatic plants like Pistia and Eichhornia. In banana, pineapple, and Chrysanthemum, the lateral branches originate from the basal.
Take one flower each of the families Fabaceae and Solanaceae and write its semi-technical description. Also, draw their floral diagram after studying them.
This family was earlier called Papilionoideae, a subfamily of family Leguminosae. It is distributed all over the world.
- Vegetative characters: Trees, shrubs, herbs, root with root nodules Stem: erect or climber
- Leaves: alternate, pinnately compound or simple, leaf base, pulvinate, stipulate, venation reticulate.
- Floral characters: Inflorescence: racemose Flower: bisexual, zygomorphic Calyx: Sepals five, gamosepalous, imbricate aestivation.
- Corolla: Petals five, polypetalous,
papilionaceous, consisting of a posterior standard, two lateral wings, two anterior ones forming a kneel (enclosing stamens and pistil), vexillary aestivation.
- Androecium: ten, diadelphous, anther dithecous
- Gynoecium: Ovary superior, monocarpellary, unilocular with many ovules, style
- Fruit: legume, seed, one to many, non- endospermic
- Economic Importance: Many plants belonging to the family are sources of pulses (gram, arhar, sem, moong, soyabean); edible oil (soyabean, groundnut); dye (indigofera); fibres (sunhemp); fodder (Sesbania, Trifolium), ornamentals (lupin, sweet, pea); medicine (muliathi).
It is a large family, commonly called as the ‘potato family’. It is widely distributed in tropics, subtropics and even temperate zones
Plants mostly herbs, shrubs, and small trees
- Stem: herbaceous rarely woody, aerial; erect, cylindrical, branched, solid of hollow, hairy or glabrous, underground stem in potato (Solanum tuberosum)
- Leaves: alternate, simple, rarely pinnately compound, exstipulate; venation reticulate
- Inflorescence: Solitary, axillary, or cymose as in Solanum
- Flower: bisexual, actinomorphic
- Calyx: sepals five, united, persistent, valvate aestivation.
- Corolla: petals five, united; valvate aestivation Androecium: stamens five, epipetalous
- Gynoecium: carpellary, syncarpous; ovary superior, bilocular, placenta swelled with many ovules.
- Fruits: berry or capsule
- Seeds: many, endosperms
- Floral Formula:
- Economic Importance: Many plants belonging to this family are sources of food (tomato, brinjal, potato), spice (chili); medicine (belladonna, ashwagandha); fumigatory (tobacco); ornamentals (petunia).
Describe the various types of placentations found in flowering plants.
- The flower is a condensed shoot which is specialised to take part in sexual reproduction of angiosperms.
- Part of Flower. A flower is generally raised above the point of origin by means of a stalk called a pedicel. Base of flower is broadened to accommodate all the components. It is called thalamus.
- It has condensed nodes and internodes. The various parts of the flower are called floral organs. They are of four types – sepals, petals, stamens and carpels.
- Sepal or Calyx. They are green, foliaceous outermost and lowermost floral organs. They can be free (polysepalous) or fused (gamosepalous). An extra whorl of green bracts called epicalyx occurs in many members of the family Malvaceae.
- The major function of sepals is protection and support to other floral organs. Petals or Corolla. They are brightly coloured flat leaf-like floral organs which lie inner to sepals and outside the stamens.
- Petals may be free (polypetalous) or fused (gamopetalous). Their major function is to attract pollinating animals.
- Stamens or Androecium. They are male reproductive organs or microsporophylls of a flower. Stamens may be borne directly over the thalamus or attached to petals (epipetalous).
- Stamens can be free or fused by their filaments (adelphous condition), anthers (syngenesious) or both (synandrous).
- Each stamen has a thread-like stalk or filament and knob-like anther. Anther is bilobed and tetrasporangiate. Pollen grains are formed inside the sporangia of anther.
- Carpels or Gynoecium. They are mega- sporophylls or female reproductive organs of the flower. Carpels may be free (apocarpous) or fused (syncarpous).
- It has three parts – stigma, style and ovary. Stigma is the terminal part of the pistil which is specialized to receive and nourish the pollen grains. Style is a stalk that raises the stigma above the ovary.
- Ovary is the basal swollen part which internally bears ovules over the placenta. Ovules later ripen to form seeds while ovary develops into a fruit.
What is a flower? Describe the parts of a typical angiosperm flower.
A flower is a reproductive unit in angiosperms:
It is meant for sexual reproduction. A typical flower has four different kinds of whorls arranged successively on the swollen end of the stalk or pedicel, called thalamus or receptacle. These are calyx, corolla, androecium and gynoecium.
The calyx is the outermost whore of the flower and the members are called sepals.
Generally, sepals are green leaf-like and protect the flower in the bud stage. The calyx may be gamosepalous (sepals united) or polysepalous (sepals free).
Corolla is composed of petals. Petals are usually brightly colored to attract insects for pollination may be free or united. The shape and colour of corolla vary greatly in plants. Corolla may be tubular, bell-shaped, funnel-shaped or wheel-shaped.
The androecium is composed of stamens. Each stamen which represents the male reproductive organ consists of a stalk or a filament and an anther. Each anther is usually bilobed and each lobe has two chambers, the pollen sacs. The pollen grains are produced in pollen-sacs. When stamens are attached to petals, they are epipetalous as in brinjal or epiphyllous when attached to perianth as in the flowers of lily. The stamens may be united into one bundle (monadelphous) as in China rose, or two bundles (diadelphous) as in pea, or into more than two bundles (polyadelphous) as in citrus.
The gynoecium is the female reproductive part of the flower and is made up of one or more carpels. A Carpel consists of three parts namely stigma, style, and ovary. The ovary is the enlarged basal part, on which lies the elongated tube, the style. The style connects the ovary to stigma. The stigma is usually at the tip of the style and is the receptive surface for pollen grains. Each ovary bears one or more ovules attached to a flattened, cushion-like placenta.
How do the various leaf modifications help plants?
- Leaves are often modified to perform functions other than photosynthesis.
- They are converted into tendrils for climbing as in peas or into spines for defence as in cacti.
- The fleshy leaves of onion and garlic store food. In some plants such as Australian acacia, the leaves are small and short-lived.
- The petioles in these plants expand, become green and synthesise food.
- Leaves of certain insectivorous plants such as pitcher plant, venus-fly trap are also modified leaves and get nitrogen from prey.
Define the term inflorescence. Explain the basis for the different types of Inflorescence in flowering plants.
The arrangement of flowers on the floral axis is termed an inflorescence. Depending on whether the apex gets converted into a flower or continues to grow, two major types of inflorescences are defined-racemose and cymose. In the racemose type of inflorescences, the main axis continues to grow, the flowers are borne laterally in acropetal succession. In the cymose type of inflorescence the main axis terminates in a flower, hence is limited in growth.
Write the floral formula of an actinomorphic, bisexual, hypogynous flower with five united sepals, five free petals, five free stamens and two united carpels with superior ovary and axile placentation.
Describe the arrangement of floral members in relation to their insertion on the thalamus.
- Based on the position of calyx, corolla and androecium in respect of the ovary on the thalamus, the flowers are described as hypogynous, perigynous and epigynous.
- In the hypogynous flower, the gynoecium occupies the highest position while the other parts are located below it. The ovary in such flowers is said to be superior, e.g., Mustard, China rose etc.
- If gynoecium is situated in the centre and other parts of the flower are located on the rim of the thalamus almost at the same level, it is called perigynous.
- The ovary here is said to be half inferior e.g., Pea (disc-shaped perigynous), Plum (cup-shaped perigynous).
- In an epigynous flower, the thalamus grows upward enclosing the ovary completely and getting fused with it, the other parts of the flower arise above the ovary.
- Hence, the ovary is said to be inferior as in flowers of guava and cucumber and the ray florets of sunflower.
1st PUC Biology Plant Kingdom Additional Questions and Answers
1st PUC Biology Plant Kingdom One Mark Questions
Garlic is a good example of
A good example of a stolon bearing plant is
Bombax (silk cotton) is a good example of
multifoliate compound leaf.
Name the kind of phyllotaxy in Hibiscus.
Name two plants that produce rhizome.
What is heterophylly?
Heterophylly refers to the presence of leaves of more than one shape on a plant.
What is a cladode?
Cladode is a phylloclade of one or two ‘ internodes.
What is pulvinus?
The swollen leaf base is called a pulvinus.
Morphology is the branch of science or biology that studies the external features of an organism.
What are adventitious roots?
Adventitious roots are those roots which arise from any part of the plant, other than the radicle.
What are tendrils?
Tendrils are slender, spirally coiled structures that help the weak-stemmed plants to climb on the support.
What is a leaf lamina?
The leaf lamina is the green expanded part of the leaf with veins and veinlets.
What is a bract?
Bract is a reduced leaf-like structure found at the base of the pedicel of a flower.
What is a staminode?
Staminode is a sterile stamen, that does not produce pollen grains.
What are parthenocarpic fruits?
Parthenocarpic fruits are those fruits which develop without fertilization of the ovary
1st PUC Biology Plant Kingdom Two Marks Questions
How is a stolon different from a sucker in plants? Give an example of each.
|It is an aerial branch of the stem that bends down and touches the ground||It is a branch of a stem arising from the underground part of the main stem|
|When the tip is buried in the soil, buds produce adventitious roots above the ground Eg: Jasmine||It grows horizontally under the ground and produces a leafy shoot Ex: Chrysanthemums|
What is a root cap? What is its function?
The root cap is the thimble-like structure that covers the root apex/tip. It protects the tender apex of the root as it penetrates through the soil.
What are nodes and internodes?
Nodes are the regions on the stem where leaves arise. Internodes are the regions on the stem between two nodes.
What is a petiole? Mention the function of the petiole.
The stalk of the leaf is called a petiole
- It helps to hold the leaf blade to the light
- It also helps the blade to flutter in wind.
What is a seed? What are the two major parts a seed consists of?
A fertilised and mature ovule is called a seed. A seed has two parts.
- An embryonal axis
- One or two cotyledons
What are trimerous flowers? Which group of plants has trimerous flowers?
Trimerous flowers are those where the floral appendages are in threes or multiples of three. Monocotyledonous plants generally have trimerous flowers.
What are coleoptile and coleorhiza?
- Coleoptile is the sheath that covers and protects the plumule fn cereal grains.
- Coleorhiza is the protective sheath of the radicle in cereal grains.
What is the Aleurone layer? Where is it found?
Aleurone layer is a layer of cells rich in proteins, that separates the embryo from the endosperm in cereal grains like rice, maize, wheat, etc.
What is endosperm? Name two plants where endosperm is absent.
The endosperm is the tissue that stores food materials for the developing embryo, it develops as a result of triple fusion in double fertilization. The endosperm is absent in
Name the plant and its family, from which colchicine is obtained.
Colonicine is obtained from Colchicum autumnale. The plant belongs to the family Liliaceae.
1st PUC Biology Plant Kingdom Three Marks Questions
How are plants classified based on their life span? Give an example each?
Based on the life-span, plants are classified into
- Annuals – plants which complete their life-cycle in one season eg: mustard, sunflower
- Biennials- plants which complete their life-cycle in two seasons
eg: radish, beetroot
- Perennials – plants which live for a number of years and produce flowers and fruits at specific seasons every year eg: mango, tamarind.
Define venation. Differentiate between reticulate and parallel venation.
Venation refers to the arrangement of veins and veinlets on the lamina of leaf
|Reticulate venation||Parallel venation|
|The midrib & other branches of veins are irregularly distributed to form a network||The veins run parallel to one another and no network is formed on the lamina|
|It is characteristic of dicot plants||It is characteristic of monocot plants|
How is marginal placentation different from parietal placentation? Give an example of each.
|Marginal placentation||Parietal placentation|
|It is found in the monocarpellary, unilocular ovary.||It is found in syncarpous ovaries.|
|Placentae are found along the ventral suture, formed by the fusion of margins of a carpel. eg: pea, bean||carpels are fused laterally and the placentae develop on the ovary wan as many as numbers of carpels eg: cucurbits, mustard.|
What is a floral diagram? Describe.
A floral diagram is the diagrammatic representation of the ground plan of a flower. It provides information about.
- The number of floral parts
- Their arrangement and interrelationships among various floral parts
The position of the mother axis with respect to the flower is indicated by a dot on top of the floral diagram – calyx, corolla, androeium and gynoeium are represented in successive whorls with calyx being the outermost.
What is pneumatophore? How do they help the plant? Name an example.
Roots that grow vertically upwards and come” above the soil surface are called pneumatophores. They bear openings called pneumatophores for the exchange of gases.
This feature is an adaptation for plants growing in marshy/swampy areas, where oxygen is deficient in the soil. These roots help the plants to get oxygen from the air for respiration. Eg: Rhizophora.
1st PUC Biology Plant Kingdom Five Marks Questions:
What are herbs, shrubs, and trees among plants? Give an example for each. What is the criterion for this classification?
(a) Herbs: They are small seasonal plants with soft stem
(b) Shrubs: They are medium-sized plants with woody stems that branch profusely from the base and attain a bushy appearance
(c) Trees: These are plants with a short and tall trunk with profuse branching.
Eg: Mango, Neem. Plants are classified on the basis of height and strength of stems.
What is a flower? Describe the parts of a typical angiosperm flower.
A flower is a modified shoot, meant for reproduction in angiosperms. A typical flower has a stalk called pedicel and four different kinds of appendages arranged in successive whorls on the swollen end of the axis called the thalamus. The outermost whorl is the calyx and consists of sepals. The next inner whorl is the corolla and consists of petals. The third whorl is the androeium which is composed of stamens. The fourth and innermost whorl is the gynoecium which is composed of carpels. The calyx and corolla are called accessory whorls and the androeium and gynoecium are called essential reproductive whorls.
Describe vexillary aestivation along with a diagram name an example.
It is found in papilionaceous corolla. The posterior vexillum or standard petal is completely external and overlaps the two lateral wing petals.
The other margin of each of the wing petals overlaps the margin of the keel petals. Keel petals are the smallest and anterior and their other margins are fused together.
Eg: Pea, Bean
Write five differences between a dicot seed and a maize grain.
|Dicot seed||Maize Grain|
|It is a seed that has developed from the ovule||It is a single-seeded fruit, the ovary modified|
|The seed coat is distinct from the fruit wall||The seed coat is completely fused with the pericarp single cotyledon|
|Two cotyledons Endosperm is absent||Single cotyledon Endosperm is present|
|There is no proactive sheath for the plumule and radicle||The plumule is protected by coleoptile and radicle by coleorhiza|
Name one plant of Fabaceae, that yields each of these:
- Edible oil – Arachis hypogea
- Dye – Indigofera
- Fibres – Crotalariajuncea
- Medicine – Trigonella
- Fodder -Trifolium