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 botany pollination and fertilization types of pollination cross pollination pollination and its types

Pollen grains do not germinate on the stigma of the same flower. The phenomenon is

  1. Prepotency

  2. Self sterility

  3. Dicliny

  4. Dichogamy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
When a pistil having functional female gametes fails to set seeds with viable and fertile pollen, which can bring about fertilisation in another pistil, the pistil and pollen are said to be incompatible and this is known as incompatibility. 
When the sexual incompatibility is between individuals of different species, it is interspecific.
When the sexual incompatibility is between individuals of same species, it is intraspecific. This intraspecific incompatibility is also called as self-incompatibility which may include many reasons like pollen fail to germinate on the surface of the stigma of the same flower, which is also known as self-sterility.
So, the correct answer is B.
Multiple choice botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

Transfer of pollen between two plants is 

  1. Cross pollination

  2. Self pollination

  3. Pollen transfer

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

The transfer of pollen from an anther of a flower of one plant to a stigma of a flower of another plant of the same species by the action of wind, insects etc is known as cross pollination. 

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Name the phenomenon of two flowers, one having long stamens and short styles, and other having short stamens and long style

  1. Allogamous device

  2. Heterostyly

  3. Dicliny

  4. Herkogamy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Heterostyly is the presence of 2 or 3 types of flowers within the same plant and such flowers differ in the length of style and stamens. Example, Primula which shows distyly.
It has two types of flowers:
1. Pin eyed flowers: These have long styles with short stamens.
2. Thrum eyed flowers: These have a short style and long stamens.
So, the correct answer is B.
Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

In dimorphic flowers, cross pollination is contrived by 

  1. Dicliny

  2. Dichogamy

  3. Herkogamy

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

Heterostyly is a form of polymorphism. In this condition, styles are of different lengths relative to the stamens in flowers. This reduces self pollination and promotes cross pollination. Primrose plants shows heterostyly.

Thus, the correct answer is option D.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Non-transfer of pollen from anther to stigma of the same flower due to a physical barriers is called as 

  1. Dichogamy

  2. Herkogamy

  3. Heterostyly

  4. Homogamy
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Herkogamy - common strategy employed by hermaphroditic angiosperms to reduce sexual interference between male and female function. It differs from other such strategies by supplying a spatial separation of the anthers and stigma.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

When the pollen grains are not transferred from anthers to the stigma in flower due to the barrier or fence, it is referred or when some natural barrier exists between androecium and gynoecium to check self pollination, it is known as _____________.

  1. Heterostyly

  2. Herkogamy

  3. Dichogamy

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

Herkogamy is a probable strategy applied by hermaphroditic angiosperms to reduce sexual interference between male and female function. It varies from other such strategies by supplying a spatial parting of the anthers and stigma.

Heterostyly is referring to the condition of having styles of different lengths, These are relative to the stamens in the flowers of various individual plants for reducing self-fertilization.

Dichogamy is the condition in which the male and female reproductive organs of the flower mature at different times to ensure that self-fertilization does not occur.

Cleistogamy refers to the self-fertilization which occurs within a permanently closed flower.

So option B is correct.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Which one of the following is not a device to promote cross-pollination?

  1. Herkogamy

  2. Dichogamy

  3. Cleistogamy

  4. Heterostyle
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Cleistogamy is not a device to promote cross-pollination as the flowers remain closed and they promote self-pollination. For example, Balsam, Oxalis and Viola anthers dehisce inside closed flowers. 

Herkogamy, dichogamy and heterostyly are the devices which promote cross-pollination. Herkogamy is a mechanical device to prevent self-pollination. For example in Pansy, stigma lies inside a flap.
In dichogamy, anthers and stigma mature at different times which ensures cross-pollination. When anthers mature earlier, it is known as protandry as in sunflower and when stigmas mature earlier it is known as protogyny as in Gloriosa.
In heterostyly, there are 2 or 3 different types of flowers with different heights of stamens and stigmas which prevent self-pollination as in jasmine. 
Thus, the correct answer is option C. 

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

The pollen of apple germinates easily on the stigma than the pollen of another flower. This tendency is known as

  1. Prepotency

  2. Self sterility

  3. Dichogamy

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In some plants when the stigma receives pollen from the same flower as well as from the other flower simultaneously, the foreign pollen germinates vigorously and fertilize the ovule.

So the correct option is 'Prepotency'.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Faster and better growth of pollen from other plants than the pollen from the same plant is?

  1. Self incompatibility

  2. Dichogamy

  3. Monocliny

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

Self-incompatibility is the widespread mechanism in flowering plants which prevents the inbreeding and promotes the outcrossing. Dichogamy is the mechanism when the stigma and anther mature at different times.  Monocliny i.e. Bisexuality is applicable for bisexual flowers. Pollen prepotency is the mechanism when the pollen of a different flower germinates faster than of the same flower thus preventing autogamy.

Thus, the correct option is D.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Barrier to avoid self pollination between stamens and pistils is

  1. Heterostyly

  2. Herkogamy

  3. Dichogamy

  4. Dicliny
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Plants have adapted various ways to prevent self pollination, such as:
Heterostyly- It is the occurrence of 2-3 types of flowers within the same plant and such flowers have the difference in length of styles and stamens.
Herkogamy- It is the condition in which the flower structure is such that even being bisexual, the pollen grains fail to reach the stigma. In some flowers, a mechanical barrier exists between the compatible pollen and stigma so that self pollination is not possible. Sometimes, there is a hood like covering that covers the stigma.
Dichogamy- It is the condition when the anther and stigma mature at different times. Either anthers dehisce before the stigma becomes receptive (called protandry) or stigma becomes receptive before anthers dehisce (called protogyny).
Dicliny- It is the presence of only one kind of reproductive whorl in a flower. It is also called unisexuality.
Therefore, from all of the above measures, herkogamy is the one in which self pollination is prevented by floral barriers between stamens and pistils.
So, the correct answer is B.
Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Nontransfer of pollen from anther to stigma of the same flower due to a mechanical barrier is

  1. Dichogamy

  2. Herkogamy

  3. Heterostyly

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

Dichogamy- It is the condition when the anther and stigma mature at different times. Either anthers dehisce before the stigma becomes receptive (called protandry) or stigma becomes receptive before anthers dehisce (called protogyny).

Herkogamy- It is the condition in which the flower structure is such that even being bisexual, the pollen grains fail to reach the stigma. In some flowers, a mechanical barrier exists between the compatible pollen and stigma so that self pollination is not possible. Sometimes, there is a hood like covering that covers the stigma.
Heterostyly- It is the occurrence of 2-3 types of flowers within the same plant and such flowers have the difference in length of styles and stamens.
Cleistogamy- It is a phenomenon, where flowers never open and in such flowers, only self-pollination occurs within the bud (unopened flower). 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. 
Thus, from all the options given in question, mechanical barrier to prevent the transfer of pollen grains from the anther to the stigma is found in Herkogamy.
So, the correct answer is B.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types

Which is not a correct explanation of cross pollination?

  1. Pollen grains of male flowers are transferred to stigma of female flowers

  2. Pollen grains are transferred from one flower to another flower of another plant of the same species

  3. Pollen grains are transferred from one flower to another flower situated on the same species

  4. Pollen grains of one flower are transferred to the stigma of the same flower
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Cross-pollination involves the transfer of pollen from one flower to another. Transferring pollen to the same flower is self-pollination, not cross-pollination.

Multiple choice botany pollination and fertilization types of pollination cross pollination pollination and its types
Gloriosa superba exhibits

  1. Heterostyly

  2. Self sterility

  3. Herkogamy

  4. Cleistogamy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
In Gloriosa superba, flower structure is such that inspite of being bisexual the pollen grains are not able to reach the stigma. The anther dehisce outwardly at a distance from the stigma and therefore, pollen can't fall on the stigma and self-pollination is prevented. This adaptation by Gloriosa to prevent self-pollination by means of floral barriers is called Herkogamy.
So, the correct answer is C.