Module: | Pollination & Outbreeding Devices
Q47: Consider the following statements regarding temporal and physical outbreeding devices:
1. Protandry is an outbreeding device where the anthers mature and shed their pollen well before the stigma of the same flower becomes receptive.
2. Protogyny is an outbreeding device where the stigma becomes receptive long after the pollen of the same flower is completely shed.
3. Herkogamy involves the presence of a natural physical or structural barrier between the anther and stigma of the same flower to prevent self-pollination.
Which of the above statements is/are correct?
2. Protogyny is an outbreeding device where the stigma becomes receptive long after the pollen of the same flower is completely shed.
3. Herkogamy involves the presence of a natural physical or structural barrier between the anther and stigma of the same flower to prevent self-pollination.
Which of the above statements is/are correct?
✅ Correct Answer: B
The correct option is B. Statements 1 and 3 are correct, but Statement 2 is incorrect.
To avoid the genetic depression caused by continuous inbreeding, angiosperms utilize various structural and temporal outbreeding devices (dichogamy). Protandry (literally "first male") is a temporal mechanism where pollen is released before the stigma is mature, common in sunflowers and cotton.
Protogyny ("first female") is the exact opposite temporal mechanism.
Statement 2 defines it backward: in protogyny, the stigma matures and becomes fully receptive to foreign pollen much earlier, before the flower's own anthers dehisce and shed pollen (e.g., in Ficus and Aristolochia). Herkogamy, on the other hand, is a physical mechanism.
Even if both organs mature simultaneously, structural barriers, such as the stigma being positioned far above the anthers or possessing a protective flap, make autogamy mechanically impossible.
To avoid the genetic depression caused by continuous inbreeding, angiosperms utilize various structural and temporal outbreeding devices (dichogamy). Protandry (literally "first male") is a temporal mechanism where pollen is released before the stigma is mature, common in sunflowers and cotton.
Protogyny ("first female") is the exact opposite temporal mechanism.
Statement 2 defines it backward: in protogyny, the stigma matures and becomes fully receptive to foreign pollen much earlier, before the flower's own anthers dehisce and shed pollen (e.g., in Ficus and Aristolochia). Herkogamy, on the other hand, is a physical mechanism.
Even if both organs mature simultaneously, structural barriers, such as the stigma being positioned far above the anthers or possessing a protective flap, make autogamy mechanically impossible.