Exercises: Reproduction in Plants | Class 7 Oxford Science: Chapter Notes, Worksheets & Tests PDF Download

Objective type questions 

A. Fill in the blanks with the correct words. 
Q.1. The male and female reproductive cells called ___________form a single cell called ____ (gametes/zygote). 

The male and female reproductive cells called gametes form a single cell called zygote.

Gametes are the reproductive cells in plants that fuse during fertilization to form a zygote, which develops into a new individual.

Q.2. ___________ (Spores/Fragments) are microscopic single-celled or several-celledd reproductive bodies that are mostly spherical in shape. 

 Spores are microscopic single-celled or several-celled reproductive bodies that are mostly spherical in shape.
Spores are a type of reproductive structure found in some plants, such as ferns and mosses. They are usually small and round, and can develop into new individuals under favorable conditions.

Q.3. ___________ (Grafting /Tissue culture) is a method used for large scale multiplication to develop better variety of crops and to save endangered species of plants. 

Tissue culture is a method used for large scale multiplication to develop better variety of crops and to save endangered species of plants.
Tissue culture is a technique used by plant biologists to grow new plants from small pieces of tissue, such as leaf or stem cells. This method is used for mass propagation of plants and to preserve rare or endangered species.

Q.4. ________(Pollination/Fertilization) is the first step in the process of seed formation. 

Pollination  is the first step in the process of seed formation.
Pollination is the transfer of pollen from the male reproductive organ of a flower to the female reproductive organ, which leads to fertilization and the formation of seeds.

Q.5. The__________ (fruit/flower) is the seed-bearing part of a flowering plant.

The fruit is the seed-bearing part of a flowering plant. 
After fertilization, the ovary of a flower develops into a fruit, which protects and nourishes the seeds inside. The fruit is an important reproductive structure in plants, as it helps in seed dispersal and ensures the survival of the species.

B. Write T for the True and F for the False statements. Correct the false statements. 
Q.1. Plants can only reproduce by asexual methods. 

False
Plants can reproduce through asexual methods such as vegetative propagation, where new plants are produced from parts of an existing plant such as leaves, stems, or roots. They can also reproduce sexually through the fusion of male and female gametes.

Q.2. An algae multiplies by the process of layering. 

False
Algae can reproduce through various methods including asexual reproduction where daughter cells are formed by cell division, sexual reproduction where male and female gametes fuse, and fragmentation where cells break off from the parent and grow into new individuals.

Q.3. The pistil bears the anthers that contain female gametes. 

False
The pistil is the female reproductive organ of a flower and consists of three parts - the stigma, style, and ovary. The stigma is the topmost part of the pistil and is where the pollen lands and germinates to form a pollen tube that grows down to the ovary. The anthers, on the other hand, are the male reproductive organs of a flower and produce and release pollen grains that contain male gametes.

Q.4. After successful pollination, the stigma secretes nutrients. 

False
After successful pollination, the pollen tube reaches the ovules in the ovary and the male gametes fertilize the female gametes to form a zygote. The ovary at the base of the pistil then develops into a fruit that encloses the seeds and protects them from external damage. The stigma does not secrete nutrients but acts as a landing platform for the pollen grains.

Q.5. Wind blows away pollen grains from anthers of one flower to the stigma of another flower. 

False
Wind is one of the common agents of pollination in plants where pollen grains are carried away from the anthers of one flower to the stigma of another flower by the wind. This is called anemophily and is seen in plants such as grasses and trees. Other agents of pollination include insects, birds, bats, and water.

Choose the correct option.

Very short answer type questions Give two examples for the following

Plants that multiply by fragmentation - Spirogyra and Bryophyllum

Q.2. Plants that multiply by their tuberous roots  _________ _________

Plants that multiply by their tuberous roots - Sweet potato and Dahlia

Q.3. Plants that have corms  _________ _________

Plants that have corms - Gladiolus and Crocus

Q.4. Plants that multiply by cutting  _________ _________

Plants that multiply by cutting - Rose and Chrysanthemum

Q.5. Plants that multiply by layering  _________ _________

Plants that multiply by layering - Jasmine and Blackberry

Q.6. Plants that pollinate by wind   _________ _________

Plants that pollinate by wind - Maize and Coconut

Q.7. Plants that pollinate by water  _________ _________

Plants that pollinate by water - Vallisneria and Hydrilla

Q.8. Plants whose seeds disperse through explosion  _________ _________

Plants whose seeds disperse through explosion - Balsam and Touch-me-not

Short answer type questions 

Underground stems are swollen due to the accumulation of food reserves in them. This helps in the survival of the plant during adverse conditions such as drought or winter.

Q.2. Differentiate between the following!
a. Asexual and sexual reproduction
b. Self-pollination and cross-pollination

a. Asexual reproduction is the process of producing offspring without involving the fusion of gametes, while sexual reproduction involves the fusion of male and female gametes.
b. Self-pollination is the transfer of pollen from the anther of a flower to the stigma of the same flower or another flower on the same plant, while cross-pollination is the transfer of pollen from the anther of a flower to the stigma of a flower on a different plant of the same species.

Q.3. Why do seeds need to disperse? 

Seeds need to disperse to ensure the survival and growth of the plant species. Dispersal helps in reducing competition among plants for resources and also helps in colonizing new areas. It also helps in avoiding inbreeding and maintaining genetic diversity in the population.

Long answer Type Questions 

Tissue culture involves the following steps:

a) Selection of a suitable plant tissue from the desired plant species.

b) Sterilization of the plant tissue to remove any bacteria or fungi.

c) Placing the tissue in a nutrient-rich medium containing growth hormones such as auxins and cytokinins.

d) Incubation of the tissue in a controlled environment with appropriate temperature, light, and humidity conditions.

e) Regular monitoring and maintenance of the tissue culture to ensure proper growth and development.

f) Subculturing of the tissue culture to obtain multiple copies of the desired plant species.

Q.2. What are the advantages of vegetative reproduction? 

The advantages of vegetative reproduction are:

a) The offspring produced are genetically identical to the parent plant.

b) It is a faster and more efficient way of reproducing plants than sexual reproduction.

c) It allows for the propagation of desirable traits and characteristics in plants.

d) It is useful in the propagation of plants that are difficult to grow from seeds.

e) It allows for the production of large numbers of plants in a short period of time.

Q.3. What happens after successful pollination? 

After successful pollination, the following events take place:

a) The pollen tube grows down the style towards the ovary.

b) The male gamete travels down the pollen tube and fuses with the female gamete to form a zygote.

c) The fertilized ovule develops into a seed.

d) The ovary develops into a fruit.

e) The seed disperses and germinates, giving rise to a new plant.

Q.4. Explain with examples, the different ways in which seeds disperse.

The different ways in which seeds disperse are:

a) Wind dispersal - Seeds that are light and have wing-like structures are carried away by the wind. Examples include dandelions and maple trees.

b) Water dispersal - Seeds that are buoyant can float away in water. Examples include water lilies and coconut trees.

c) Animal dispersal - Some seeds have hooks or barbs that attach to animal fur or clothing. Examples include burdock and cocklebur.

d) Explosive dispersal - Some plants have seed pods that explode, scattering the seeds. Examples include the touch-me-not plant and the violets.

e) Gravity dispersal - Seeds that are heavy and have no special structures to aid in dispersal fall directly beneath the parent plant. Examples include the apple tree and the peach tree.