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प्रश्न
Why angiosperm anthers are called dithecous?
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उत्तर
Typical angiosperm anther is broad, terminal and bilobed. Each lobe of the anther has two pollen sacs which fuse (at maturity) to form a single chamber called the thecus, so it is called dithecous.
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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?
Draw a diagram of a section of a megasporangium of an angiosperm and label funiculus, Micropyle, embryosac and nuclleus.
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.
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.
What are the adaptations which are required in self-pollinated plants?
Pollination by water occurs in ______.
Which of the following floral adapation are adapted by hydrophilous flowers?
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 | ______ |
