Question

What is a sterile flower?

Answer 1

Hint: The fertility of the flowers is due to its reproductive whorls. The reproductive whorls are the androecium and gynoecium.

Complete answer:
A flower in which essential whorls are non-functional are called sterile flowers. These flowers have staminodes or pistillodes. These flowers never get fertilized. Sterile flowers are often used for artificial selection and they serve as an additional feature to attract pollinating agents towards the plant.

Additional information:
A flower is a modified and condensed shoot; it is the reproductive part of angiosperms. A flower consists of four whorls which are as follows:

> Calyx- It is the first and outermost whorl whose individual members are called sepals. Its function is protection and photosynthesis.

> Corolla- It is the first whorl whose individual members are called petals. Its main function is attracting insects to bring about pollination.

> Androecium- It is the male reproductive whorl whose individual members are stamens. The stamen consists of anther and filament. Pollen grains are produced in anther.

> Gynoecium- it is the female reproductive whorl whose individual members are carpels or pistils. The carpel consists of stigma, style and ovary. The ovary contains ovules. Double fertilization takes place in ovary.

- Calyx and corolla are accessory whorls as they do not take part in reproduction whereas androecium and gynoecium form essential whorls as they take part in reproduction.
- A flower containing all four whorls is called a complete flower and absence of any one or more whorls is an incomplete flower. When the essential whorls are missing, the flower is called neuter.
- A flower in which essential whorls are missing is called neuter. Example- Ray florets of Sunflower. They are called sterile because they lack stamens and carpels. They have colorful petals thus, they help in attracting insects. These insects bring about pollination.

Note: A complete flower will have four whorls named as calyx, corolla, androecium and gynoecium. Calyx and corolla are called accessory or non-essential whorls as they do not take part in pollination while the androecium and gynoecium are called reproductive or essential whorls.