Biology · Science General

Botany and Plant Science

5,038 Questions

Botany and plant science delve into the biological study of plant life, covering structural anatomy, physiological processes, and reproductive mechanisms. Key topics include inflorescence patterns, root modifications, and seed development, which are vital for biology sections in medical entrance exams. This collection of practice questions helps solidify understanding of complex plant functions.

Plant ReproductionPlant AnatomyRoot ModificationsInflorescence PatternsPlant Morphology

Botany and Plant Science Questions

Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

During self pollination of Mirabilis, 

  1. Flowers are closed

  2. Flowers are open and growing style brings the stigma in contact with anthers

  3. Filaments bring anthers in contact with stigma

  4. Style bends to bring stigma in contact with anthers
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Mirabilis has homogamous flowers. Homogamous flowers are the bisexual flowers in which anthers and stigma mature at the same time. Thus, self pollination occurs in Mirabilis. When the anthers and stigma mature, the filaments of anther recoil to bring them in contact with the stigma and as the anthers dehisce, pollen grains are deposited on the surface of the stigma. Thus, self pollination occurs in this way.
So, the correct answer is C.
Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

A mechanism to prevent cross pollination is

  1. Protogyny

  2. Protandry

  3. Heterostyly

  4. Cleistogamy
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A mechanism to prevent cross-pollination is called cleistogamy. It is a condition in which flower does not open. In such flowers, the anthers and sigma lie close to each other. When anther dehisces in the flower buds, pollen grains come in contact with stigma to effect pollination, e.g., Arachis hypogea. It ensures seed formation even in the absences of any pollination agent. It is cheaper for the plant as there is no costly nectar or fragrance which the plant has to produce for pollination.

Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Assured seed set is possible even in absence of pollinators when flower is

  1. Xenogamous

  2. Chasmogamous

  3. Geitonogamous

  4. Cleistogamous.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
•Xenogamous flowers are the flowers in which pollen are transferred from the anther to the stigma of a different flower on different plant. Xenogamous flowers are cross pollinated and depend on external agencies for pollination.
•Chasmogamous flowers are the flowers which have exposed anthers and stigma and thus, both self pollination and cross pollination can occur. Chasmogamous flowers may also depend on external agencies for cross pollination.
•Geitonogamous flowers are the flowers in which pollen are transferred from the anther to the stigma of other flower on the same plant. These flowers also need external agencies for pollination.
•Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs. Cleistogamous flowers are not dependent on external agencies for pollination. Hence, seed setting is not dependent on pollinators.
Hence, assured seed set is possible even in the absence of pollinators when the flower is Cleistogamous.
So, the correct answer is D.
Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Cleistogamy is effective in

  1. Oryza sativa

  2. Brassica campestris

  3. Allium cepa

  4. Pisum sativum.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs. In Oryza sativa (rice), anther and stigma mature before the opening of the flower and thus, self-pollination is promoted.
Hence, cleistogamy is effective in Oryza sativa.
So, the correct answer is A.
Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Bisexual flower which never opens is

  1. Homogamous

  2. Heterogamous

  3. Dichogamous

  4. Cleistogamous
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A bisexual flower which never opens is cleistogamous. It is a condition in which flower does not open. It is an adaptation seen in plants to ensure self-pollination. In such flowers, the anthers and stigma lie close to each other. When anther dehisces in the flower buds, pollen grains come in contact with stigma to effect pollination, e.g., Arachis hypogaea. 

Thus, the correct answer is  D.

Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Cleistogamous flower is found in

  1. Tobacco

  2. Mirabilis

  3. Viola

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cleistogamy is a type of automatic self-pollination of certain plants that can propagate by using non-opening, self-pollinating flowers. The largest genus of cleistogamous plants is Viola.

So the correct option is 'Viola'.

Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

In Catharanthus ($=$ Vinca) anthers occur near the mouth of corolla tube. Self pollination is performed by.

  1. Growth of style

  2. Bending of filaments

  3. Shedding of pollen and falling on the low lying stigma

  4. Entry of insect
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The anthers and stigmas of chasmogamous or the open flowers are brought together by the growth, bending as well as by folding. In Catharanthus, the growth of style brings the stigma in contact of ripe anthers present on the mouth of corolla tube When cross-pollination fails in Sunflower, the bifid bent style stigma curls back so as to pick the pollen sticking to the surface of style. It is a fail-safe mechanism of self-pollination.

So the correct option is A.

Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Cleistogamous flowers are

  1. Male female which never open

  2. Female flowers which never open

  3. Bisexual flowers which never open

  4. Open bisexual flowers which perform self pollination in bud condition
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs. 
So, the correct answer is C.
Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

In Tape Grass ($=$ Vallisneria).

  1. Both male and female flowers break from the plant and float on the surface of water

  2. Only the female flowers break from the plant while the male flowers are brought to the surface by long stalks

  3. Only the male flowers break from the plant and rise to the surface while the female flowers are brought to the surface by long pedicels

  4. Any of the two types of flowers can break
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Tape grass is a submerged hydrophyte. It is a dioecious plant with the flowers borne underwater. The male flowers detach on maturity and float on the surface of the water while the female flowers grow underwater and they come up to the surface with the help of their thin long stalk.

So the correct option is C.

Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Lever or turn - pipe mechanism of pollination occurs in.

  1. Salvia

  2. Antirrhinum

  3. Phlox

  4. Gloriosa
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In Salvia, pollination is entomophilous, which means it occurs by insects. Pollination occurs by the lever or turns pipe mechanism. The petals of the Salvia are bifurcated. When the insect visits some flower and sits on the petals, then the stamens are brought down to the touch the back of insect and pollen are laden on it.

When the insect visits another flower, cross-pollination occurs.

 Thus, the correct answer is A.

Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Continued self pollination results in

  1. Self incompatibility

  2. Gametes lose vigour

  3. Inbreeding depression

  4. Formation of unisexual flowers.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Continued self-pollination over many generations leads to the accumulation of recessive deleterious alleles, a phenomenon known as inbreeding depression.

Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Identify the correct pair of statements.
(i) White kernel of Coconut is a free nuclear endosperm
(ii) In dioecious plants, autogamy is prevented but geitonogamy occurs
(iii) Cleistogamous flowers are always self pollinated
(iv) Castor is an endospermic seed.

  1. i, ii

  2. iii, iv

  3. ii, iv

  4. ii, iii
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
•Coconut has free nuclear endosperm. During the development of a nuclear type of endosperm, the primary endosperm mother cell divides by free nuclear divisions, and these divisions are not followed by cell wall formation. Thus, the free nuclei remain in the cytoplasm of the embryo sac. These nuclei now arrange themselves towards the periphery of the embryo sac and centripetal wall formation occurs that finally leads to a cellular type of endosperm. Thus, the kernel of coconut is cellular endosperm.
•Dioecious plants have unisexual male and female flowers on different plants i.e. a plant may have either male flowers or female flowers but not both. Dioecious plants prevent Autogamy which is the transfer of pollen from the anther to the stigma of the same flower, as only unisexual flowers are there. Also, Geitonogamy which is the transfer of pollen from the anther to the stigma of another flower on the same plant is prevented because male and female flowers are not present on the same plant.
•Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs.
•Castor is an endospermic seed in which endosperm is not fully consumed by the growing embryo and it is persistent in the seed.
Hence, from all the statements given in the question, statements (iii) and (iv) are correct.
So, the correct answer is B.
Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Above ground cleistogamous flowers are formed late in the season in

  1. Balsam

  2. Viola

  3. Oxalis

  4. All the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs. Example of Cleistogamous flowers is Viola. Viola has two kinds of flowers, Chasmogamous flowers that are formed on the upper branches in early season, which are pollinated by insects and Cleistogamous flowers that are formed above the ground late in the season.
So, the correct answer is B.
Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types
Cleistogamy does not require anthesis because

  1. No pollination agent is required

  2. It assures heterozygosity

  3. It allows xenogamy

  4. It favours insect pollination
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Anthesis is the flowering period in which flowers are fully opened.
Cleistogamy is the phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). Bisexual flowers which do not open at all are called cleistogamous. In such flowers, anthers and stigma lie close to each other. When the anthers dehisce in the flower buds, pollen grains come in contact with the stigma and pollination occurs. Cleistogamous flowers are not dependent on external agencies for pollination.  Since, Cleistogamous flowers have self pollination and don't depend on pollination agents, anthesis is required in them as these flowers do not open at all.
So, the correct answer is A.
Multiple choice biology pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Both autogamy and geitonogamy cannot occur in

  1. Papaya

  2. Cucumber

  3. Castor

  4. Maize
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Autogamy is the kind of self pollination in which pollens are transferred from the anther to the stigma of the same flower. Geitonogamy is the kind of self pollination in which pollens are transferred from the anther of one flower to the stigma of another flower on the same plant.
Papaya is a dioecious plant i.e. it has male and female flowers on separate plants. Hence, neither Autogamy nor Geitonogamy can occur. So, the correct answer is A.