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प्रश्न
Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.
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उत्तर
Cross-pollination cannot occur in cleistogamous flowers. Cleistogamous flowers do not open at all. In these flowers, the anthers and stigma are close together; when the anthers dehisce in the flower buds, pollen grains touch the stigma, resulting in pollination. As a result, these flowers are always self-pollinated since they remain closed, and cross pollen cannot land on the stigma. Cleistogamous flowers can pollinate and set seeds without pollinators.
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संबंधित प्रश्न
As a senior biology student you have been asked to demonstrate to the students of secondary level in your school, the procedure(s) that shall ensure cross-pollination in a hermaphrodite flower. List the different steps that you would suggest and provide reasons for each one of them.
Explain the post-pollination events leading to seed production in angiosperms.
A flower of tomato plant following the process of sexual reproduction produces 200 viable seeds.
Answer the following questions giving reasons :
(a) What would have been the minimum number of ovules present in pre-pollinated pistil ?
(b) How many microscope mother cells would minimally be required to produce requisite number of pollen grains ?
(c) How many pollen grains must have minimally pollinated the carple ?
(d) How many male gametes would have used to produce these 200 viable seeds ?
(e) How many megaspore mother cells were required in this process ?
Why angiosperm anthers are called dithecous?
Write two ways in which pollination may occur in plants.
Exine and intine are the parts of
Name of the part of the ovary which gives rise to:
Fruit ______
Coelacanth was caught in South Africa. State the significance of the discovery of Coelacanth in the evolutionary history of vertebrates.
Name the two types of pollination.
What is a flower? Draw a typical flower and label its different parts.
Write different modes of pollination in detail with suitable examples.
What are the adaptations which are required in self-pollinated plants?
Give an account of any two biotic agents for pollination along with their adaptations.
Pollination occurs in ______.
Which of the following pair has haploid structures?
Chief pollinators of agricultural crops are ______.
Which of the following is not a water pollinated plant?
Which of these is a condition that makes flowers invariably autogamous?
In some plants anther and stigma mature at the same time this condition is called ______.
Pollination refers to the ______.
Autogamy can occur in a chasmogamous flower if ______.
Choose the correct statement from the following:
What is ornithophily?
What are the major abiotic factors that influence habitat?
Name the following:
One plant each of Hypohydrophily and epihydrophily.
Complete the following table:
| Sr. | Type of pollination | Agent | Kind of flower | Examples |
| (i) | ______ | Wind | ______ | Maize |
| (ii) | Chiropterophily | ______ | Dull colour, with strong fragrance, abundant nectar | Adansonia |
| (iii) | Entamophily | Insects | ______ | Rose/Jasmine |
| (iv) | Ornithophily | ______ | Brightly coloured, large and showy. They secrete profuse, dilute n ectar | ______ |
Briefly discuss any two methods by which plants avoid self-pollination.
Identify the set of correct statements:
- The flowers of Vallisneria are colourful and produce nectar.
- The flowers of waterlily are not pollinated by water.
- In most of water-pollinated species, the pollen grains are protected from wetting.
- Pollen grains of some hydrophytes are long and ribbon like.
- In some hydrophytes, the pollen grains are carried passively inside water.
Choose the correct answer from the options given below:
