Question

20. (a) What is pollination? Give its types.
(b) Draw a longitudinal section of female reproductive part of a flower showing germination of pollen grain.
Label on it the following: (i) stigma, (ii) pollen tube with a male germ cell, (iii) female germ cell (egg).​

Answer 1

Answer:

there is two types of pollination:

a

1) self pollination

2) cross pollination

Answer 2

(a) Pollination is when pollen grains from an anther, the male portion of a flower, are transferred to a female part in the flower, known as the stigma. In order for pollination to be successful, the pollen grains transferred must be from a flower of the same species.

After the pollen grains land on the stigma, they create a pollen tube through the length of the style or stalk connecting the stigma and ovary. Once the pollen tube is complete, the pollen grain will send sperm cells from the grain down to the ovary. When the sperm cells reach the ovary and the egg cells, fertilization will occur, which will result in the formation of the seed. The seed will then be released from the parent plant and will be able to grow into a plant and continue the reproductive cycle using the method of pollination.

Types of Pollination

Although all flowering plants rely on pollination for reproduction, there is a variation in how plants pollinate. There are two types of pollination, called self-pollination and cross-pollination.

1. Self-pollination is the more basic type of pollination because it only involves one flower. This type of pollination occurs when pollen grains from the anther fall directly onto the stigma of the same flower. Although this type of pollination is simple and quick, it does result in a reduction in genetic diversity because the sperm and egg cells of the same flower share genetic information.
2. Cross-pollination is a more complex type of pollination that involves the transfer of pollen from the anther of one flower to the stigma of a different flower. This type of pollination results in an increase in genetic diversity because the different flowers are sharing and mixing their genetic information to create unique offspring.

(b) Refer attachment.