Tag: pollination, fertilization and development of endosperm and embryo

Questions Related to pollination, fertilization and development of endosperm and embryo

When a red flowered plant was cross pollinated by white flowered one and the offspring were self pollinated to obtain a phenotypic ratio of 1:2:1, it has to be a case of -

botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Incomplete dominance

  2. Co-dominance

  3. Recessive epistasis

  4. Pleurotropic effect of genes

Show answer
Correct Option: A
Explanation:

Incomplete dominance or blending dominance is a type of inheritance where the hybrid is not related to either of the parents but exhibit a blending of characters of the two parents.

It shows the ratio of 1:2:1 instead of the normal 3:1 phenotypic ratio.
So, the correct option is 'incomplete dominance'


Transfer of pollen from one flower to stigma of another flower of same species is termed as

botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Cross-pollination

  2. Pollination

  3. Self-pollination

  4. None of the above

Show answer
Correct Option: A
Explanation:
  • Cross-pollination is the transfer of pollen from the anthers of one flower to the stigma of another flower by the action of wind, insects, etc. 
  • The two plants genetic material combines and the resulting seeds from that pollination will have characteristics of both varieties and is a new variety. 
  • Sometimes cross-pollinating is used intentionally in the garden to create new varieties. So option A is correct.

Statement $1$ : In pea plant, transfer of pollen grains to the stigma is easy.
Statement $2$: In cross pollinating plants, pollination does not take place.

botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Both statements $1$ and $2$ are correct

  2. Statement $1$ is correct but statement $2$ is incorrect

  3. Statement $1$ is incorrect but statement $2$ is correct

  4. Both statements $1$ and $2$ are incorrect

Show answer
Correct Option: B
Explanation:

In pea, anthers and stigma are present close to each other therefore pollination is easy while in cross pollinating plants pollination takes place with the help of an external agency.

So, the correct answer is 'statement 1 is correct but statement 2 is incorrect'

Heterostyly as a contrivance for cross-pollination is found in.

botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Pennisetum

  2. Impatiens

  3. Primula vulgaris

  4. Oenothera

Show answer
Correct Option: C
Explanation:

Heterostyly is the presence of $2-3$ types of flower with different heights of styles and stamens. In diheterostyly (dimorphic heterostyly), there are two types of flower, pin eyed (long style and short stamens) and thrum eyed(short style and long stamens), e.g., Primula vulgaris (primrose), jasmine.

So, the correct answer is 'Primula vulgaris'

The process of removing stamens of a flower during the hybridization process is called as________________

botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Hybridization

  2. Emasculation

  3. Sterilisation

  4. Crossing

Show answer
Correct Option: B
Explanation:

  • Emasculation is the removal of stamens or anthers or killing the pollen of a flower without the female reproductive organ is known as emasculation. In bisexual flowers, emasculation is essential to prevent self-pollination. In monoecious plants, male flowers are removed or male inflorescence is removed. 
  • In species with large flowers e.g., (cotton, pulses) hand emasculation is accurate and it is adequate. In species with large flowers, removal of anthers is possible with the help of forceps. It is done before anther dehiscence. 
  • The corolla of the selected flower is opened with the help of forceps and the anthers are carefully removed with the help of forceps. 
  • An efficient emasculation technique should prevent self-pollination and produce a high percentage of seed set on cross-pollination.
Therefore, the correct answer is option B.

By cross pollinating certain tobacco species, some fertile hybrids were obtained by

botany pollination, fertilization and development of endosperm and embryo types of pollination cross pollination pollination and its types

  1. Mendel

  2. Morgan

  3. Kolreuter

  4. Khorana.

Show answer
Correct Option: C
Explanation:

In tobacco, due to the continuous self-pollination, homozygosity increases. It results in the occurrence of inbreeding depression, and the plants are called Inbred lines. When these inbred lines are subjected to hybridization, fertile hybrids are obtained. This is called Hybrid vigour or heterosis. This was developed by Kolreuter.

So, the correct option is ‘Kolreuter’.

Both chasmogamous and cleistogamous flowers are present in

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

  1. Helianthus

  2. Commelina

  3. Rosa

  4. Gossypium

Show answer
Correct Option: B
Explanation:

Commelina produces two types of flower chasmogamous flowers which are similar to the flower of other species with exposed anthers and stigma, and cleistogamous flowers which do not open at all. In such flowers, the anthers and stigma lie close to each other. When anthers dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, cleistogamous flowers are invariably autogamous as there is no chance of cross-pollen landing on the stigma. Cleistogamous flowers assure seed-setting even in the absence of pollinators. 

So, the correct answer is 'Commelina'.

How can plants prevent self pollination?

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

  1. Plants should produce bisexual flowers

  2. Pistil should have increased receptivity for pollens from same plant

  3. Stamen and pistil mature at different times

  4. All of the above

Show answer
Correct Option: C
Explanation:

Plants prevent self-pollination by following methods:-

i) Making stamen and pistil mature at different times known as incompatibility.
ii) By producing unisexual flowers.
iii) Pollen release and stigma receptivity are not synchronised.
So, the correct option is 'Stamen and pistil mature at different times'.

Flowering plants have developed certain outbreeding devices to discourage self-pollination and encourage cross-pollination. One of these is not an example of such outbreeding device.

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

  1. Dicliny

  2. Dichogamy

  3. Herkogamy

  4. Cleistogamy

Show answer
Correct Option: D
Explanation:

Cleistogamous flowers are intersexual. They remain closed causing self-pollination. Cleistogamy occurs late in the flowering season in some plants. e.g., Commelina, balsam, Oxalis, Viola. These plants possess both chasmogamous and cleistogamous flowers. In cleistogamous flowers, the anthers dehisce inside closed flowers. The growth of style brings the pollen grains in contact with stigma. Cleistogamy ensures self-pollination. So, the correct answer is 'Cleistogamy'.

Advantage of cleistogamy is ..................

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

  1. More vigorous offspring

  2. Non-dependence on pollinators

  3. Vivipary

  4. Higher genetic variability

Show answer
Correct Option: B
Explanation:

Cleistogamy procedure do not depend on pollinators. It is because, cleistogamy is automatic self-pollination which describes the trait of certain plants to propagate by using non-opening, self-pollinating flowers. Especially well known in peanuts, peas and beans, this behaviour is most widespread in the grass family.