Question

Why do androecium and gynoecium of the same flower mature at different times?

Answer 1

Hint:Flowers that have both androecium and gynoecium are called hermaphroditic flowers or bisexual flowers. In these flowers as a mechanism of preventing the self-pollination, androecium and gynoecium of the same flower matures at different times.


Complete answer: Androecium is known as the male part of a flower while gynoecium is the female part of a flower. In a bisexual or hermaphrodite flower, when androecium and gynoecium matures at different times, the phenomenon is referred as ‘Dichogamy’. It is nature's mechanism for avoiding self pollination and promoting cross pollination. Self pollination is the transfer of pollen grains from anther to stigma of the same flower or another flower of the same plant. Self pollination isn’t desirable because it doesn’t help in providing variations in the next generation.
Flower arrangement patterns (inflorescence) and other physiological barriers may affect the time at which the androecium and gynoecium mature in the same flower.
If the gynoecium matures early, this condition is known as protogyny
And if androecium matures early this condition is known as protandry.
Both protogyny and protandry leads to cross pollination.

Additional information:
Dichogamy is considered as the maturation of sex organs in plants at different times. In extent it may be complete or partial (incomplete). Dichogamy may be intrafloral or interflora. In former, it exists within a flower, in later; it is expressed among flowers in diclinous species (having the stamens and pistils in separate flowers). It can be interpreted as a floral mechanism favouring cross-pollination. Protandry and protogyny are safeguards against self-pollination.

Note: Dichogamy is a cross-pollination promoting device. In this, the bisexual flower promotes cross-pollination by maturing the carpel and stamen at different times. It is widespread in angiosperms and mainly divided in two main types, protandry and protogyny.