Correct option is D
Explanation:
The pollen-to-ovule ratio (P:O ratio) in plants reflects their reproductive strategy and is influenced by pollination mechanism and mating system.
Pollination Mechanism and P:O Ratio
- Entomophilous (Insect-Pollinated) species require less pollen since insects efficiently transfer pollen to stigmas.
- Anemophilous (Wind-Pollinated) species require a much higher quantity of pollen because wind dispersal is random and inefficient.
Mating System and P:O Ratio
- Bisexual (Hermaphroditic) Species: Have both male and female reproductive organs in the same plant, leading to efficient pollen use and a lower P:O ratio.
- Dioecious Species: Have separate male and female individuals, requiring a larger amount of pollen to ensure successful fertilization, leading to a higher P:O ratio.
· Anemophilous species produce excessive pollen due to the inefficiency of wind dispersal.
· Dioecious species require even more pollen because male and female individuals are separate, making pollination even less certain.
· This results in the highest pollen-to-ovule ratio, making Anemophilous Dioecious species the most skewed case.
Information Booster:
· Entomophilous dioecious species – Lower P:O ratio since insect pollination is efficient, even in dioecious plants.
· Entomophilous bisexual species – Very low P:O ratio due to self-pollination and targeted pollination.
· Anemophilous bisexual species – High P:O ratio but less than anemophilous dioecious species since pollen can be used more efficiently within the same flower.
