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प्रश्न
Give scientific reason.
Fertilization in plants is called double fertilization.
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
Answer the following question.
What is pollination? Explain the different types of pollination.
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
How is the process of pollination different from fertilization?
The anther contains ______.
Name the swollen lower part of the carpel.
Name the male part of the flower.
Where is the female gamete formed in flowering plants?
Fill in the following blank with suitable word :
The ovary of a flower becomes ....... after fertilisation.
Explain the terms 'self pollination'
Explain the term 'fertilisation'.
What is seed? What are the parts of a seed? Explain with the help of a labelled diagram.
What is meant by 'unisexual flowers' and 'bisexual flowers'? Give two examples of each.
Fill in the blanks:
A stamen consists of ______ and ________.
State whether the following statement is true (T) or false (F):
Stamens make egg cells.
State whether the following statement is true (T) or false (F):
Flowers which possess stamens and carpel are called unisexual.
Mention the function of Stigma.
“Cell division is a type of reproduction in unicellular organism.” Justify.
Draw a diagram of the longitudinal section of a flower and label the following parts.
__________ is present in unisexual flower.
Find an odd one out.
Calyx : Sepals : : Corolla : ________________
Bisexual : Hibiscus : : Unisexual : ___________
Accessory whorls : Calyx and corolla : : essential whorls : ______________
Pollen grains from anther are transferred to the stigma.
Write the functions of sepals
Observe the figure below. Write functions of the labelled parts.
The male reproductive part of a flower is ______.
Write the events involved in the sexual reproduction of a flowering plant.
Discuss the first event and write the types.
Where does the endothecium layer of anther lobes is present?
The 3-celled egg apparatus at the micropylar end comprises of ______
Gloriosa superba exhibits ______.
Sperm and egg nuclei fuse due to ______.
The process of release of eggs from the ovary is called ______
State the number of sets of chromosomes present in a zygote.
Name the reproductive parts of an angiosperm. Where are these parts located? Explain the structure of its male reproductive part.
The pollen tube usually enters the embryo sac ______.
Consider the following three flowers namely X, Y and Z. Which flower(s) would develop into a fruit?
| Flower X | Flower Y | Flower Z |
 |
 |
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