CBSE 2025 · Region 6 · Set 1 · Q22 · 3 marks
Flowering plants with hermaphrodite flowers have developed many reproductive strategies to ensure cross-pollination. Study the given outbreeding devices adopted by certain flowering plants and answer the questions that follow. \backslashbox{Stigma}{Pollen grains} Pollen grains of Plant A Pollen grains of Plant B Pollen grains of Plant C Stigma of Plant A × ✓ ✓ Stigma of Plant B ✓ × ✓ Stigma of Plant C ✓ ✓ ×
Note : All plants belong to the same species. × - No pollen tube growth/inhibition of pollen germination on stigma. ✓ - Pollen germination on stigma.(a)Name and define the outbreeding device described in the above table.(b)Explain what would have been the disadvantage to the plant in the absence of the given strategy.
Flowering plants with hermaphrodite flowers have developed many reproductive strategies to ensure cross-pollination. Study the given outbreeding devices adopted by certain flowering plants and answer the questions that follow.
Note : All plants belong to the same species. × - No pollen tube growth/inhibition of pollen germination on stigma. ✓ - Pollen germination on stigma.
| \backslashbox{Stigma}{Pollen grains} | Pollen grains of Plant A | Pollen grains of Plant B | Pollen grains of Plant C |
| Stigma of Plant A | × | ✓ | ✓ |
| Stigma of Plant B | ✓ | × | ✓ |
| Stigma of Plant C | ✓ | ✓ | × |
(a)
Name and define the outbreeding device described in the above table.
(b)
Explain what would have been the disadvantage to the plant in the absence of the given strategy.
Marking-scheme solution
(a)
Self incompatibility ,It is a Genetic mechanism to prevent self-pollen (from the
same flower or other flower of same plant) from fertilising the ovules by inhibiting pollen germination or pollen tube in the pistil/ non-synchronisation of pollen release and stigma receptivity, Either the pollen is released before the stigma becomes receptive or stigma becomes receptive much before the release of pollen
(b)
It would have led to inbreeding depression
Sexual Reproduction in Flowering PlantsPre-fertilisation: Structures and EventsUnderstandshort_answermedium
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CBSE Class 12 Biology past-paper question from the 2025board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.