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प्रश्न
Describe an activity to demonstrate phototropism.
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उत्तर
To demonstrate phototropism in plants a sunflower plant is taken and kept in sunlight. It will be observed that the flower head of sunflower will move from east to west along with the movement of Sun. This shows that the flower head of sunflower is positively phototropic and moves in response to sunlight stimulus.
संबंधित प्रश्न
What is the function of a flower?
What is made in anther of a flower?
When an insect sits on the flower of a plant then some particles A present in the top of little stalks in the flower attach to its body hair. When this insect now sits on the flower of another similar plant, then particles A attached to the hair of insect are put on the top of a flask-shaped organ at the centre of flower. The particle A grows a long tube b from the top of flask-shaped organ through which C moves down and reaches the bottom part of flask-shaped organ. Here C fuses with the nucleus of d contained in structure E. the fusion of C and D forms a new cell f which grows and develops into a seed of the plant.
(a) What are particles A? What is the process of transferring A from one flower to another flower of similar plant by the insect known as?
(b) What is the name of tube B?
(c) What is C which moves down through the tube B?
(d) Name D and E.
(e) What is F?
What are the male and female gametes in a flowering plant?
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.
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
Bisexual : Hibiscus : : Unisexual : ___________
Accessory whorls : Calyx and corolla : : essential whorls : ______________
Where is the zygote located in the flower after fertilization?
Triple fusion involves ______.
