Plants can use several mechanisms to reduce the chances of self-fertilization. Which of the following is not one of these mechanisms?
Group of answer choices
A. the formation of dioecious plants
B. stamen and carpels that mature at different times
C. brightly colored bracts that replace petals
D. self-incompatibility
E. anthers and stigma that are structurally arranged to prevent pollen transfer in the same flower
The correct answer is C. brightly colored bracts that replace petals. This is not a mechanism used by plants to reduce the chances of self-fertilization.
To determine which of the given options is not a mechanism used by plants to reduce self-fertilization, let's go through each option and understand what it means:
A. The formation of dioecious plants: Dioecious plants refer to plants that have separate male and female individuals. This means that one plant will only have male flowers and another plant will only have female flowers. This mechanism prevents self-fertilization since the male and female reproductive organs are physically separated. This is a valid mechanism to reduce self-fertilization.
B. Stamen and carpels that mature at different times: Stamen refers to the male reproductive organ, while carpels refer to the female reproductive organ in plants. If stamen and carpels mature at different times, the plant can avoid self-fertilization because the male and female organs will not be simultaneously receptive. This is another valid mechanism to reduce self-fertilization.
C. Brightly colored bracts that replace petals: Bracts are modified leaves that surround and protect flowers. While brightly colored bracts may help attract pollinators like bees or butterflies, they do not directly play a role in preventing self-fertilization. Plants can have colorful bracts and still have mechanisms to reduce self-fertilization. Therefore, option C is the correct answer as it is not a mechanism to reduce self-fertilization.
D. Self-incompatibility: Self-incompatibility is a genetic mechanism in plants that prevents self-fertilization. It occurs when a plant has genetic controls that prevent it from accepting its own pollen. This acts as a defense mechanism to promote outcrossing, where pollen from another plant is required for fertilization. Self-incompatibility is a valid mechanism to reduce self-fertilization.
E. Anthers and stigma that are structurally arranged to prevent pollen transfer in the same flower: Anthers are the male reproductive organs that produce pollen, while the stigma is the female reproductive organ that receives pollen for fertilization. If the anthers and stigma are structurally arranged in a way that prevents pollen transfer within the same flower, it will also reduce the chances of self-fertilization. This is a valid mechanism to reduce self-fertilization.
Therefore, the correct answer is C. Brightly colored bracts that replace petals, as it is not a mechanism used by plants to reduce self-fertilization.