The condition necessary for reproduction to occur between plants P and Q after pollination is that plants P and Q should be

Step 1: Analyze the question The question asks what must be true of plants P and Q for reproduction to succeed after pollination. Pollination alone (the transfer of pollen to the stigma) does not guarantee reproduction. Fertilisation must also occur.

Step 2: Explain the concept After a pollen grain lands on a stigma:

1. It must recognise and be accepted by the stigma. This is a chemical compatibility check.
2. It then germinates and grows a pollen tube down the style.
3. The male gamete fuses with the ovule's egg cell (fertilisation).

This compatibility exists mainly between plants of the same species. Pollen from a different species is usually rejected, because the stigma does not support its germination and the genetic material is incompatible. Fertilisation therefore fails.

Step 3: Evaluate the options

• A. Of the same species. Correct. Same-species plants have compatible pollen and stigma, so the pollen tube can grow and fertilisation can occur.
• B. Brightly coloured. Colour only helps attract pollinators before pollination. It plays no part in fertilisation afterward.
• C. Well scented. Like colour, scent attracts insects before pollination. It is irrelevant once pollen has landed.
• D. Of different species. Incorrect. Cross-species pollen is usually incompatible, so reproduction normally fails.

Step 4: Answer The correct answer is A. of the same species.

Exam tip: Remember that colour and scent are for attracting pollinators (before pollination), while species compatibility is for fertilisation (after pollination). If a question says "after pollination", think compatibility, pollen tube growth and fertilisation, not attraction.