Tag: botany

Questions Related to botany

Allogamy is favoured by

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

  1. Homogamy

  2. Cleistogamy

  3. Monocliny

  4. Dicliny

Show answer
Correct Option: D
Explanation:
Allogamy, also known as cross pollination, is the transfer of pollen grains from the anther of one flower to the stigma of another flower borne on a separate plant.
Dicliny is the presence of only one kind of reproductive whorl in a flower. It is also called unisexuality.
A plant may be monoecious i.e. male and female flowers are present on the same plant. In such cases, both cross pollination and self pollination can occur.
Or the plant may be dioecious i.e. male and female flowers are present on different plants. In such cases, only cross pollination can occur. Thus, dicliny favours allogamy or cross pollination.
So, the correct answer is D.

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

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

  1. Herkogamy

  2. Dichogamy

  3. Cleistogamy

  4. Heterostyle

Show answer
Correct Option: C
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. 

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

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

  1. Prepotency

  2. Self sterility

  3. Dichogamy

  4. All of the above

Show answer
Correct Option: A
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'.

Which of the following plants shows the tendency of prepotency?

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

  1. Guava

  2. Apple

  3. Grapes

  4. Both B and C

Show answer
Correct Option: D
Explanation:

Prepotency is the phenomenon in which Pollen grains of another flower of the same species germinate more rapidly over the stigma, in comparison to the pollen grains of the same flower. For example Apple, Grape, etc.

So the correct answer is D.

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

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

  1. Self incompatibility

  2. Dichogamy

  3. Monocliny

  4. Prepotency

Show answer
Correct Option: D
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.

Barrier to avoid self pollination between stamens and pistils is

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

  1. Heterostyly

  2. Herkogamy

  3. Dichogamy

  4. Dicliny

Show answer
Correct Option: B
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.
Dicliny is found in
botany pollination and fertilization types of pollination cross pollination pollination and its types

  1. Calotropis

  2. Cucurbita

  3. Crotalaria

  4. Pisum

Show answer
Correct Option: B
Explanation:
Dicliny is the presence of only one kind of reproductive whorl in a flower. Dicliny is thus called unisexuality. In dicliny, a plant may be monoecious i.e. both male and female flowers are borne on the same plant or the plant may be dioecious i.e. male and female flowers are borne on different plants. Among all the options given in the question, Calotropis, Pisum and Crotalaria have bisexual flowers. But, Cucurbita is monoecious plant. Thus, Cucurbita exhibit dicliny. So, the correct answer is B.

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

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

  1. Dichogamy

  2. Herkogamy

  3. Heterostyly

  4. Cleistogamy

Show answer
Correct Option: B
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.

Which is not a correct explanation of cross pollination?

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

  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

Show answer
Correct Option: D

In Kigellia pinnate/ Sausage Tree, pollination is performed by.

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

  1. Bats

  2. Birds

  3. Insects

  4. Wind

Show answer
Correct Option: A