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प्रश्न
Give scientific reason.
Fertilization in plants is called double fertilization.
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उत्तर
- The pollen grain germinates over the stigma and gives rise to pollen tube.
- The pollen tube bursts and releases two male gametes in the embryo sac.
- One male gamete fuses with the egg cell to form the zygote, whereas the second male gamete fuses with two polar nuclei in the embryo sac to form an endosperm.
- Since, in flowering plants, the process of fertilization occurs twice in the same embryo sac, by two male gametes, it is called as double fertilization.
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संबंधित प्रश्न
Match the following:
| Column A | Column B |
| (i) Stigma | (a) Neuron |
| (ii) Pepsin | (b) Carpel |
| (iii) Dendrites | (c) Protein |
| (d) Stamen |
Name the parts A, B and C shown in the diagram and write their functions.
(i) Name the part marked 'A' in the diagram.
(ii) How dose 'A' reachese part 'B'?
(iii) State the importance of the part 'C'.
(iv) What happens to the part marked 'D' after fertilisation is over?
Name and differentiate between the two modes of pollination in flowering plants.
Give one example of a unisexual flower.
Mention the changes a flower undergoes after fertilisation.
You are asked by your teacher to study the different parts of an embryo of a gram seed. Given below are the steps to be followed for the experiment:
I. Soak the gram seeds in plain water and keep them overnight.
II. Cut open a soaked seed and observe its different parts.
III. Take some dry gram seeds in a petri dish.
IV. Drain the excess water.
V. Cover the soaked seeds with a wet cotton cloth and leave them for a day.
The correct sequence of these steps is :
(A) III, I, V, IV, II
(B) III, I, II, IV, V
(C) III, IV, V, I, II
(D) III, I, IV, V, II
State the function of flowers in the flowering plants.
How does the process of fertilisation take place in flowers?
What is the name of female part of a flower?
Where is the female gamete formed in flowering plants?
Fill in the following blank with suitable word :
Flowering plants reproduce by ...........method of reproduction.
Fill in the following blank with suitable word :
The female organ of reproduction in the flower is the...........
Explain the term 'fertilisation'.
Name the part of a seed which contains stored food.
Name the part of a seed which grows into root.
Which among the following statements are true for unisexual flowers?
(i) They possess both stamen and pistil
(ii) They possess either stamen or pistil
(iii) They exhibit cross pollination
(iv) Unisexual flower possessing only stamens cannot produce fruits
(a) (i) and (iv)
(b) (ii), (iii) and (iv)
(c) (ii) and (iii)
(d) (i), (iii) and (iv)
In a bisexual flower, inspite of the young stamens being removed artificially, the flower produces fruit. Explain.
Multiple choice question. Tick (✓) the correct choice:
The male gamete is present inside the which germinates.
- the style
- the stigma
- the anther
- the ovary
Mention the function of Flower.
Mention the function of Stigma.
What part is played by stamens and carpels in reproduction?
Give one example each of unisexual and bisexual flowers. Differentiate between the two types of pollination that occur in flowers. What happens when a pollen lands on a suitable stigma? Write about the events that occur till the seed formation in the ovary.
You have to perform the experiment, "To identify the different parts of an embryo of a gram seed." Describe the procedure that you would follow.
“Cell division is a type of reproduction in unicellular organism.” Justify.
Distinguish between unisexual and bisexual flowers giving one example of each. Draw a diagram showing process of germination of pollen grains on stigma and label the following parts:
(a) Female germ cell
(b) Male germ cell
(c) Ovary
Answer the following question.
List two agents of pollination?
What does germination mean?
Observe the figure below. Write functions of the labelled parts.
Write the events involved in the sexual reproduction of a flowering plant.
a. Discuss the first event and write the types.
b. Mention the advantages and the disadvantages of that event.
Where does the endothecium layer of anther lobes is present?
Generally, in a pollen tube, which of the following moves to the tip of the tube?
Flowers showing ornithophily show few characteristic like ______.
The flower of the Hibiscus plant is ______
Complete the table
| Carly x | ______ | ______ |
| ______ | petal | attract insects |
| Androecium | ______ | Male reproductive part |
| ______ | ______ | Female reproductive part. |
Is the chromosome number of zygote, embryonal cells and adult of a particular organism always constant? How is the constancy maintained in these three stages?
What are the agents for pollination?
