Class 9th ICSE Biology Solutions Chapter 4 The Flower
Progress Check
Question 1.
Mention, if the following statements are true (T) or false (F):
(i) Flowers can be complete or incomplete. T/F
(ii) A flower typically has six floral whorls. T/F
(iii) Bracts are usually green, but sometimes large and colourful. T/F
(iv) Nasturtium has nectaries. T/F
(v) Stamens and catpels are die male and female parts. T/F
(vi) The prefix “gamo-” is used whenever any of the floral whorls are fused T/F
(vii) Stigma may be simple or divided into two or more lobes. T/F
(viii) Papaya is monoecious plant. T/F
Answer:
(i) True
(ii) False
(iii) True
(iv) True
(v) True
(vi) True
(vii) True
(viii) False
Review Questions
A. Multiple Choice Type :
Question 1.
Bougainvillea flower is an example of
(a) an incomplete flower
(b) having a large nectary
(c) water pollination
(d) large colourful bracts
Answer:
(d) large colourful bracts
Question 2.
A flower is said to be complete when :
(a) It has the corolla and calyx
(b) It has the corolla and gynoecium
(c) It has the androecium and gynoecium
(d) It has all the four whorls.
Answer:
(d) It has all the four whorls.
Question 3.
The part of the flower that gives rise to the fruit is
(a) Sepals
(b) Petals
(c) Ovary
(d) Stamens
Answer:
(c) Ovary
Question 4.
The part of the flower that gives rise to the seed is
(a) Ovary
(b) Placenta
(c) Ovule
(d) Pollen grains
Answer:
(c) Ovule
Question 5.
The essential whorls of a flower are the
(a) Calyx and Corolla
(b) Stamen and ovary
(c) Calyx and epicalyx
(d) Androecium and gynoecium
Answer:
(b) Stamen and ovary
B. Very Short Answer Type
Question 1.
Match the parts in column A with the flowers or parts of flower in column B.
| Column A |
Column B |
| (a) Polyadelphous | (i) Polypetalous |
| (b) Pollen grains | (ii) Calyx, corolla |
| (c) Free petals | (iii) Nectar |
| (d) Non-essential | (iv) Bombax |
| (e) Sweet fragrant fluid | (v) Pollen sac |
Answer:
(a) Bombax
(b) Pollen sac
(c) Polypetalous
(d) Calyx, corolla
(e) Nectar.
C. Short Answer Type
Question 1.
Explain the following terms :
(a) Incomplete flower
(b) Staminate flower
(c) Pistillate flower
(d) Bisexual flower
Answer:
(a) Incomplete flower –
If one or more sets of floral structures are missing, the flower is called incomplete.
(b) Staminate flower –
A flower which contains stamens i.e., male parts of flower. Requires cross-pollination.
(c) Pistillate flower –
A flower that contains a centrally located pistil that may be formed of a single female unit or a flower that contains only the carpels.
(d) Bisexual flower –
A flower which contains both stamens and carpels is called bisexual or hermaphrodite.
Question 2.
Distinguish between the following pairs :
(a) Flower and inflorescence,
(b) Petals and petaloid sepals.
Answer:
(a) Flower:
Flower is the reproductive part of the plant which is responsible for gamete formation and fertilization.
Inflorescence:
Inflorescence is the arrangement of flowers on the floral stem.
(b) Petals –
Non-essential parts of flower which help in protection of reproductive parts or make the flower attractive for pollination.
Petaloid sepals –
Sometimes sepals are undifferentiated. These taken together are called perianth. When perianth is non-green, it is described as a petaloid.
Question 3.
Where are the following structures/parts located and what are their functions?
(a) Placenta
(b) Thalamus
(c) Anther
(d) Stigma
(e) Micropyle.
Answer:
(a) Placenta –
It is present inside the ovary. Its role is to attach ovules to ovary.
(b) Anther –
It is present at the end of a stamen. Anther has poller sacs in which pollen grains are formed. Pollen grains contain the male gametes.
(c) Thalamus –
Pedicel (stalk) swells up at its tip to form a cup-shaped thalamus. All the floral whorls arise from the thalamus.
(d) Stigma –
It is the terminal knob-like part, it may be divided into two or more lobes and assume a feathery appearance. The stigma is covered with hair or with glandular papillae. It serves as the landing place grains for pollen during pollination.
(e) Micropyle –
The orifice in the coats of the ovule leading to the apex of the nucellus through which the pollen tube commonly enters.
Question 4.
Why are the following described as stated:
(a) The androecium of pea flower is diadelphous.
(b) Ray florets of sunflower as neuters
(c) Salvia sepals as petaloid
(d) China rose stamens as epipetaloid.
(e) Maize plant as monoecious
Answer:
(a) The androecium of pea flower is didelphous because the filaments are united in two bundles.
(b) Ray florets of sunflower are neuters because both male and female reproductive are lacking.
(c) Salvia sepals are petaloid as the three sepals are united and are red in colour like petals and hence, undifferentiated from the petals.
(d) China rose stamens are epipetaloid, as they arise from the base of the petals.
(e) Maize plant is monoecious because though both male and female flowers are found on the same plant, they occur in two different inflorescences.
D. Long Answer Type
Question 1.
Name the different types of androecium found in flowers.
Answer:
Depending on the stamens being free or fused, four types of androecium in flowers are:
- Polyadelphous androecium –
The stamens may be free but filaments are united in many groups, e.g. mustard. - Monadelphous androecium –
Anthers are free but filaments are united in one group, e.g. china rose, peas, hibiscus. - Diadelphous androecium –
Filaments are united in two bundles and the anthers remain free. e.g. pea, gram, beans. - Syngenesious androecium –
Filaments are free but the anthers are united, e.g. sunflower.
Question 2.
Name the type of androecium found in
(a) China rose,
(b) Bombax
(c) pea
Answer:
(a) China-rose – Monadelphous
(b) Bombax – Polyadelphous
(c) Pea – Diadelphous
E. Structured / Application / Skill Type
Question 1.
There is a flower in which you use the following names : Standard, wings and keel.
(a) Name the flower
(b) What part of the flower do the names given above refer to?
Answer:
(a) The flower is Sweet Pea.
(b) Standard –
Outermost petal which is large and broad.
Wings –
The two lateral petals are in the form of wings.
Keel –
Two wings enclose two inner petals which unite to form a keel.
Question 2.
The figure given alongisde represents generalised arrangement of the different parts of a bisexual flower. Name the parts numbered 1-10.
Answer:
- Anther
- Filament
- Ovule
- Placenta
- Stigma
- Style
- Overy
- Petal
- Sepal
- Receptacle
Question 3.
Given below are two figures (A & B) of a certain part of flower. Study the figures carefully and answer the following questions :
(a) Which major organ of a flower does the figure A represent? What is the collective term for this organs?
(b) Are the contents of the pollen sacs in B, male or female?
(c) Can you state how the contents of the pollen sacs would come out?
Answer:
(a) Stamen, collective name Androecium.
(b) Contents in the pollen sacs B, are male.
(c) Through agents like-air, wind insects leading to Pollination.
Question 4.
What are bracts? State their function.
Answer:
When a flower arises in the axil of a leaf-like structure, this structure is known as bract. It may be green like leaves or colored as in case of Bougainvillea.
Bract protect the flowers from pests and harsh weather. Some brightly coloured bracts attract pollinators. Some bracts serve as insulators, protecting the delicate flowers within from freezing weather.
Question 5.
Explain the terms Monodelphous. Didelphous and Polydelphous. In each case name a flower possessing such an androecium.
Answer:
- Monadelphous :
Stamens are united in one group by their filaments. Only anthers are free, e.g., china rose (staminal tube), cotton. - Diadelphous :
The filaments are united in two bundles. e.g., pea (out of ten, nine stamens form a staminal tube while one is free). - Polyadelphous :
The filaments are united in several groups. e.g., Bombax.
Question 6.
Write about the following pertaining to maize :
(i) Glumes,
(ii) Ears
(iii) Tassel
(iv) Paleae
Answer:
(i) Glumes –
Male flowers are in pairs. Each pair is enclosed by two bracts called glumes.
(ii) Ears –
Leafy structures covering female inflorescence.
(iii) Tassel –
The inflorescence bearing male flowers is formed at the terminal part of plant in the form of a crown called tassel.
(iv) Paleae –
The androecium consists of three stamens and is enclosed by two smaller bracts called paleae.
Question 7.
Why are the following described as stated:
(i) Maize plant as monoecious
(ii) Ray florets of sunflower as neuters
(iii) Salvia sepals as petaloid
(iv) China-rose stamens as epipetaloid.
Answer:
(i) Maize plant is monoecious because though both male and female flowers are found on the same plant, they occur in two different inflorescences.
(ii) Ray florets of sunflower are neuters because both male and female reproductive are lacking.
(iii) Salvia sepals are petaloid as the three sepals are united and are red in colour like petals and hence, undifferentiated from the petals.
(iv) China-rose stamens are epipetaloid, as they arise from the base of the petals.
Additional Questions
Question 1.
Define the following terms :
(i) Sexual reproduction
(ii) Fertilisation
Answer:
(i) SEXUAL REPRODUCTION :
“The union of male and female gametes to produce new individual is called SEXUAL REPRODUCTION.”
Or
“The fusion of sperm with Egg to form a ZYGOTE from – which the new individual develops is called SEXUAL RE-”
PRODUCTION”
(ii) FERTILISATION :
“The fusion of gametes results in the formation of a ZYGOTE from which the new individual ‘ develops. This process is called FERTILISATION.”
Question 2.
State the advantages of sexual reproduction.
Answer:
Advantages of Sexual Reproduction :
- Chances of survival of the species at times of sudden environmental changes improves.
- New combinations of traits are formed which are a step toward EVOLUTION.
- Variations resulting help to eliminate undesirable characteristics from the population.
Question 3.
Name the essential whorls of a flower and explain why they are so called.
Answer:
The ANDROECIUM [STAMEN] and GYNOECIUM [PIS¬TIL] which are essential for zygote formation are collec¬tively called ESSENTIAL WHORLS as they are directly involved in the formation of male and female cells.
Question 4.
Fill in the blanks :
(i) The male reproductive whorl of a flower is called …………………
(ii) The female reproductive whorl of a flower is called ………………….
(iii) A pollen grain has two coats called the …………… and the …………………
(iv) The ………………. connects the stigma to the ……………..
(v) Each member of the gynoecium is called a ………………..
(vi) Each pistil is made up of the ……………….. the ……………… and the ………………
Answer:
(i) Androecium
(ii) Gynoecium
(iii) The exine, The intine
(iv) Style, Ovary
(v) Pistil
(vi) Stigma, style, ovary .
ICSE Class 9 Biology Solutions