Which one of the following statements is wrong?
- When pollen is shed at two-celled stage, double fertilization does not take place.
- Vegetative cell is larger than generative cell.
- Pollen grains in some plants remain viable for months.
- Intine is made up of cellulose and pectin.
Answer
(1) When pollen is shed at two-celled stage, double fertilization does not take place.
Solution
As per NCERT, in over 60 per cent of angiosperms pollen grains are shed at the 2-celled stage (vegetative cell + generative cell); the generative cell divides inside the pollen tube to form the two male gametes.
∴ Both male gametes are still delivered into the embryo sac and double fertilisation takes place normally ⇒ statement (1) is wrong.
(2) The vegetative cell is bigger, with abundant food reserve and a large irregular nucleus; the generative cell is small and floats in its cytoplasm — correct.
(3) Pollen of some members of Rosaceae, Leguminosae and Solanaceae remains viable for months — correct.
(4) The inner wall, intine, is a thin continuous layer made of cellulose and pectin — correct.
Answer: (1)