Why is it essential for pollen to land on the stigma of a flower of the same species rather than just any surface, for reproduction to succeed?
Generated by claude-sonnet-4-6 · 2026-06-26 01:06 · grounding rag
Model Answer
Pollen must land on the stigma because it is the specific part of the pistil designed to receive pollen. After landing on a suitable (same-species) stigma, the pollen grain germinates and grows a pollen tube through the style to reach the ovule in the ovary, where fertilisation occurs. On any other surface, this tube cannot form, and fertilisation cannot take place.
Source: Chapter 7, Section 7.3.2 – Sexual Reproduction in Flowering Plants
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Explanation
- The key phrase from the textbook is "suitable stigma" — examiners expect students to use this term and explain why it must be suitable.
- Two points are needed for 2 marks: (1) the stigma is the correct/compatible surface for pollen germination, and (2) only then does the pollen tube grow through the style to fertilise the egg cell in the ovule.
- Avoid vague answers like "only the stigma can receive pollen" — explain the mechanism (pollen tube formation → fertilisation).