Advertisements
Advertisements
Question
Explain the post-pollination events leading to seed production in angiosperms.
Advertisements
Solution
Pollination is the process of transfer of pollen grains from anther to stigma.
-
When the pollen grains fall on the stigma, the pollen tube enters one of the synergids and releases two male gametes.
-
One of the male gametes moves towards the egg cell and fuses with it to form zygote.
-
The other male gamete fuses with the two polar nuclei and forms the primary endosperm nucleus. This is termed as triple fusion.
-
After the triple fusion, the central cell becomes the primary endosperm cell (PEC).
-
The primary endosperm nucleus gives rise to endosperm, while the zygote develops into embryo.
- Seeds are the fertilised ovules that are developed inside a fruit.
- The integuments of ovules harden to form the seed coat, and the micropyle facilitates the entry of oxygen and water into the seed.
APPEARS IN
RELATED QUESTIONS
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.
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?
What are chasmogamous flowers?
Differentiate between the following:
Self pollination and cross pollination.
Type of interaction where an individual sacrifices its own welfare (life) for the benefit of another animal of its own species is ______.
Explain water pollination in detail with its types.
Flowers which have single ovule in the ovary and are packed into inflorescence are usually pollinated by ______.
Advantage of cleistogamy is:
Match the Column I with Column II.
| Column I | Column II |
| A. Pea | (i) Xenogamy |
| B. Jawar | (ii) Epihydrophily |
| C. Maize | (iii) Anemophily |
| D. Vallis | (iv) Bisexual |
| E. Cannabis | (v) Geitonogamy |
Which one of the following flower is hypohydrophilous?
