(a) Explain the terms ‘self-pollination’ and ‘cross-pollination’?
(b) How do the insects help in cross-pollination?
(c) How is the process of pollination different from fertilization?
(a) (i) Self pollination: When the pollen grains from the anther of a flower are transferred to the stigma of the same flower (or another flower on the same plant), it is called self pollination.
(ii) Cross pollination: When the pollen grains from the anther of a flower on one plant are transferred to the stigma of a flower on another similar plant, it is called cross pollination.
(b) When an insect sits on the flower of a plant for sucking nectar, then the pollen grains from the anther of this flower sticks to its body. And when this insect sits on another flower of another similar plant, then the pollen grains sticking to its body are transferred to the stigma of this second flower. In this way, the insect transfers the pollen grains from the anther of flower in one plant to the stigma of flower in another plant and causes cross pollination.
(c) Pollination: In pollination, the pollens are transferred from anther to the stigma of carpel.
Fertilisation: In fertilisation, the male gamete fuses with the female gamete present in ovule inside the ovary of flower to form a fertilised egg or zygote.