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प्रश्न
How do the insects help in cross-pollination?
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उत्तर
When an insect sits on a flower, the pollens from the anther stick to their wings. The same insect when sits on another flower, the pollens from its wings stick to the stigma of that flower thereby affecting pollination.
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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 and differentiate between the two modes of pollination in flowering plants.
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
The fusion of male and female gametes is termed as ______.
Explain the term 'fertilisation'.
Which of the following statements are true for flowers?
(i) Flowers are always bisexual.
(ii) They contain sexual reproductive organs.
(iii) They are produced in all groups of plants.
(iv) after fertilization they give rise to fruits.
The students of a class were asked by the teacher to study the different parts of an embryo of an angiosperm. Given below are the essential steps for the experiment :
A. Soak the seeds in plain water and keep them overnight.
B. Cut open the soaked seed and observe its different parts.
C. Take some healthy seeds in a petri-dish.
D. Drain the excess water, cover the seeds with a wet cotton cloth and leave them as it is for a day.
The correct sequence of these steps is
(a) C, A, D, B
(b) C, D, A, B
(c) A, C, D, B
(d) A, C, B, D
Draw a diagram of a pistil showing pollen tube growth into the ovule and label the following:
Pollen grain, male gamete, female gamete, ovary.
Draw a diagram of the longitudinal section of a flower and label the following parts.
Pollen tube reaches the embryo sac via style.
Give scientific reason.
Fertilization in plants is called double fertilization.
Write the events involved in the sexual reproduction of a flowering plant.
Discuss the first event and write the types.
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.
Antipodal cells are present towards the ______ in an anatropous ovule.
In a flowering plant, archesporium gives rise to ______.
Pollen grains are produced by ______
Which among the following statements are true for unisexual flowers?
- They possess both stamen and pistil
- They possess either stamen or pistil
- They exhibit cross pollination
- Unisexual flowers possessing only stamens cannot produce fruits
Double fertilization is essential for formation of ______.
The pollen tube usually enters the embryo sac ______.
