Biology

Morphology of Flowering Plants

Question:

Describe the various types of placentations found in flowering plants.

Answer:

Placenta is a parenchymatous cushion present inside the ovary where ovules are borne. The number, position, arrangement or distribution of placentae inside an ovary is called placentation. The placentation are of different types namely, marginal, axile, parietal, basal and free central.
(i)Marginal placentation : The placenta forms a ridge along the ventral suture of the ovary and the ovules are borne on this ridge forming two rows, e.g., pea.
(ii)Axile placentation : When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentation is said to be axile, e.g., china rose, tomato and lemon.
(iii)Parietal placentation : The ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one-chambered but it becomes two-chambered due to the formation of the false septum, e.g., mustard and Argemone.
(iv)Free central placentation : When the ovules are borne on central axis and septa are absent, as in Dianthus and primrose the placentation is called free central.
(v)Basal placentation: The placenta develops at the base of ovary and a single ovule is attached to it, as in sunflower, marigold.

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Morphology of Flowering Plants

Q 1.

Reticulate venation is found in dicot leaves while in monocot leaves venation is of parallel type. Biology being a ‘Science of exceptions’, find out any exception to this generalisation.

Q 2.

How do you distinguish between hypogeal germination and epigeal germination? What is the role of cotyledon (s) and the endosperm in the germination of seeds?

Q 3.

Mango and coconut are ‘drupe’ type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?

Q 4.

Write the floral formula of an actinomorphic, bisexual, hypogynous flower with five united sepals, five free petals, five free stamens and two united carples with superior ovary and axile placentation.

Q 5.

You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a 'pitcher'? How does this modification help the plant for food even though it can photosynthesize like any other green plant?

Q 6.

In Opuntia the stem is modified into a flattened green structure to perform the function of leaves (i.e., photosynthesis). Cite some other examples of modifications of plant parts for the purpose of photosynthesis.

Q 7.

Draw diagrams of a typical monocot and dicot leaves.to show their venation pattern.

Q 8.

In swampy areas like the Sunderbans in West Bengal, plants bear special kind of roots called _______

Q 9.

Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils.
(a) Cucumber
(b) Peas
(c) Pumpkins
(d) Grapevine
(e) Watermelons

Q 10.

Match the followings and choose the correct option.

Group A

Group B

A.

Aleurone layer (i)

Without fertilization

B.

Parthenocarpic fruit (ii)

Nutrition

C.

Ovule (iii)

Double fertilization

D.

Endosperm

(iv)

Seed

Options:

  • A—(i), B—(ii), C—(iii), D—(iv)
  • A—(ii), B—(i), C—(iv), D—(iii)
  • A—(iv), B—(ii), C—(i), D—(iii)
  • A—(ii), B—(iv), C—(i), D—(iii)

Q 11.

In aquatic plants like Pistia and Eichhomia, leaves and roots are found near

Q 12.

You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a ‘pitcher’? How does this modification help the plant for food even though it can photosynthesise like any other green plant?

Q 13.

In swampy areas like the Sunderbans in West Bengal, plants bear special kind of roots called _______

Q 14.

Mango and coconut are ˜drupe' type of fruits. In mango fleshy mesocarp is edible. What is the edible part of coconut? What does milk of tender coconut represent?

Q 15.

Tendrils are found in the following plants. Identify whether they are stem tendrils or leaf tendrils,
a.Cucumber
b. Peas
c. Pumpkins  
. Grapevine
e. Watermelons

Q 16.

How do you distinguish between hypogeal germination and epigeal germination? What is the role of cotyledon (s) and the endosperm in the germination of seeds?

Q 17.

Given below are a few floral formulae of some well known plants. Draw floral diagrams from these formulae.

Q 18.

Sunflower is not a flower. Explain.

Q 19.

Tendrils of grapevines are homologous to the tendril of pumpkins but are analogous to that of pea. Justify the above statement.

Q 20.

Give two examples of roots that develop from different parts of the angiospermic plant other than the radicle.

Q 21.

Describe the arrangement of floral members in relation to their insertion on thalamus.

Q 22.

Write floral formula for a flower which, is bisexual; actinomorphic; sepals five, twisted aestivation, petals five; valvate aestivation; stamens six; ovary tricarpellary, syncarpous, superior, trilocular with axile placentation.

Q 23.

Add the missing floral organs of the given floral formula of Fabaceae. ncrt-exemplar-class-11-biology-solutions-morphology-of-flowering-plants-2 (2)

Q 24.

How can you differentiate between free central and axile placentation?

Q 25.

Describe various stem modifications associated with food storage, climbing and protection.

Q 26.

Describe modifications of stem with suitable examples.

Q 27.

Define the term inflorescence. Explain the basis for the different types of inflorescence in flowering plants.

Q 28.

Reticulate and parallel venation are characteristic of_______and_______

Q 29.

Sunflower is not a flower. Explain.

Q 30.

Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of 02, root growth is restricted or completely stopped. How do the plants growing in marshlands or swamps obtain their 02 required for root respiration?

Q 31.

You have heard about several insectivorous plants that feed on insects. Nepenthes or the pitcher plant is one such example, which usually grows in shallow water or in marsh lands. What part of the plant is modified into a 'pitcher'? How does this modification help the plant for food even though it can photosynthesize like any other green plant?

Q 32.

Rhizome of ginger is like the roots of other plants that grows underground. Despite this fact ginger is a stem and not a root. Justify.

Q 33.

Describe various stem modifications associated with food storage, climbing and protection.

Q 34.

Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of 02, root growth is restricted or com pletely stopped. How do the plants growing in marshlands or swamps obtain their 02 required for root respiration?

Q 35.

In aquatic plants like Pistia and Eichhornia, leaves and roots are found near_______

Q 36.

Which parts in ginger and onion are edible?

Q 37.

A typical angiosperm flower consists of four floral parts. Give the names of the floral parts . and their arrangements sequentially.

Q 38.

Stolon, offset and rhizome are different forms of stem modifications. How can these modified forms of stem be distinguished from each other?

Q 39.

Seeds of some plants germinate immediately after shedding from the plants while in other plants they require a period of rest before germination. The later phenomena is called as dormancy. Give the reasons for seed dormancy and some methods to break it.

Q 40.

Reticulate and parallel venation are characteristic of ________ and ______ respectively.

Q 41.

Add the missing floral organs of the given floral formula of Fabaceae.

Q 42.

The essential functions of roots are anchorage and absorption of water and minerals in the terrestrial plant. What functions are associated with the roots of aquatic plants? How are roots of aquatic plants and terrestrial plants different?

Q 43.

Tendrils of grapevines are homologous to the tendril of pumpkins but are analogous to that of pea. Justify the above statement.

Q 44.

The mode of arrangements of sepals or petals in a floral bud is known as aestivation. Draw the various types of aestivation possible for a typical pentamerous flower.

Q 45.

Define the following terms:
(a) aestivation (b) placentation
(c) actinomorphic (d) zygomorphic
(e) superior ovary (f) perigynous flower (g) epipetalous stamen.

Q 46.

What is a flower? Describe the parts of a typical angiosperm flower.

Q 47.

How do the various leaf modifications help plants?

Q 48.

How do the various leaf modifications help plants?

Q 49.

Rearrange the following zones as seen in the root in vertical section and choose the correct option.
A. Root hair zone
B. Zone of meristems
C. Rootcapzone
D. Zone of maturation
E. Zone of elongation
(a) C, B, E, A, D (b) A,B,C,D,E
(c) D, E, A, C, B (d) E, D, C, B, A

Q 50.

Namedhe body part modified for food storage in the following.
(a) Carrot________________
(b) Colocasia_______________
(c) Sweet potato_______________
(d) Asparagus_______________
(e) Radish_______________
(f) Potato_______________
(g) Dahlia_______________
(h) Turmeric_______________
(i) Gladiolus_______________
(j) Ginger________________
(k) Portulaca_______________