The reproductive part of flowering plants is the flower. You have already studied the structure and functions of floral parts of Brassica in chapter.
16.2.1 Pollination
The transfer of pollen grains (also called pollen) from anthers of a stamen to the stigma of a carpel of a flower is called pollination.
Types of pollination
There are two types of pollination, self pollination and cross pollination.
“Hay fever, is an allergic response to pollen; which are in the air, and are inhaled by us during inhalation”
The transfer of pollen in the same flower or between two flowers of the same plant is called self pollination.
Cross pollination is the transfer of pollens from one plant to another plant of the same species. The transfer of pollens may be by wind, water or by insects ( or other animals).
The characteristics of wind pollinated, insect pollinated and water pollinated flowers is given in the table 16.1.
Table 16.1 Differences among wind pollinated, insect pollinated and water pollinated flowers.
| Wind pollinated flowers | Insect pollinated flowers | Water pollinated flowers |
| 1. Flowers are small anad without bright coloured petals. | The flowers are large and have brightly coloured petals | The flowers are small and without brightly coloured petals. |
| 2. Pollens produced in enormous numbers and are light in weight. | Pollens are not produced in enormous numbers and are sticky. | The pollen grains neither sink nor float on the surface of water, due to their peculiar specific gravity. They float under water. |
| 3. The flowers have long feathery stigmas. | The stigmas are variously shaped so that pollen grains are attached or entangled there. | The flowers have long stalks. The styles are long and the stigmas are sticky. |
| 4. The filaments of stamens are long and have versatile anthers. | Stamens have short filaments and anthers are not versatile. | Stamens have short filaments and anthers are not versatile. |
| 5. The flowers do not produce nectar. | The flowers produce nectar by glands called nectarines. | Do not produce nectar. |
| 6. Examples are the flowers of maize, wheat and rice. | Examples are the flowers of most dicots e.g. Bougainvillea, rose and calotropis. | Examples are the flowers of plants such as potamogeton and Vallisneria. |
