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प्रश्न
Briefly discuss any two methods by which plants avoid self-pollination.
उत्तर
The two methods to avoid self-pollination are:
- Dichogamy - In bisexual flowers, anthers and stigma mature at different times. Due to these maturation times, self-pollination is not possible.
- Prepotency - In numerous plants, pollen grains from one flower easily germinate on the stigma of another flower that is genetically distinct, as opposed to pollen grains from the same flower. This prevents self-pollination.
APPEARS IN
संबंधित प्रश्न
A flower of tomato plant following the process of sexual reproduction produces 240 viable seeds.
Answer the following questions giving reasons :
(a) What is the minimum number of pollen grains that must have been involved in the pollination of its pistil?
(b) What would have been the minimum number of ovules present in the ovary?
(c) How many megaspore mother cells were involved?
(d) What is the minimum number of microspore mother cells involved in the above case?
(e) How many male gametes were involved in this case?
Complete the following chart and rewrite.
| Sr.No. | Agencies | type of pollination |
| 1 | Water | .................... |
| 2 | ........................... | Entomophily |
| 3 | Bat | .................... |
| 4 | ....................... | Ornithophily |
(Or)
Explain outbreeding devices in angiospermic plants.
Select and write the most appropriate answer from the given alternatives for the following subquestion:
A versatile anther is an adaptation for _______ type of pollination.
Mention any two contrivances in flowers which favour cross-pollination.
Choose the correct option of the following question:
Type of Interaction where an individual sacrifices its own welfare (life) for the benefit of another animal of its own species is:
Even in absence of pollinating agents seed-setting is assured in ______.
Heterostyly as a contrivance for cross-pollination is found in ______.
Which one of these statements is incorrect?
The following statements seem to describe the water-pollinated submerged plants.
Which type of pollination does Figure 12.1 indicate?
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 | ______ |
