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NCERT Solutions for Class 9th Science Chapter 11 .2.2 Sexual reproduction in flowering plants — In-text Questions

Book page 21511 Updated on2026-09-08

Q1.
Can you guess the function of the most attractive part of a flower — the coloured petals?
Answer

The petals attract the pollinator. They make the flower conspicuous from a distance, and in many flowers they also carry the scent glands and hold the nectar at their base.

Why a plant invests so much in petals: the plant cannot move, so its pollen must be carried to another flower's stigma. Wind will do it, but wastefully — a wind-pollinated grass has to release five to ten lakh pollen grains per flower to get 50 – 200 seeds. An insect, by contrast, flies from one flower of the same kind to another, so the pollen it carries has a good chance of arriving somewhere useful. An insect-pollinated sunflower gets 800 – 1,000 seeds from only 20,000 – 40,000 grains. The petals are what buy that accuracy.

Petals also do other jobs: they form a landing platform for the insect, many carry nectar guides — lines or patches that point the visitor to the nectar and, in passing, to the anthers and stigma — and at night they close in some plants and protect the inner parts.

Did you know? Bees see ultraviolet light, which we cannot. Many flowers that look plain yellow to us carry bold ultraviolet patterns that a bee sees as a bull's-eye around the nectar.
Q2.
You have learnt that the transfer of pollen from stamen to stigma is essential for the formation of fruits. How can you investigate it?
Answer

By an experiment that takes away the pollen, or the visitors that carry it, and sees whether fruits still form — which is exactly what Activity 11.6 does on a pea plant.

The design has three moves:

  1. Remove the stamens (emasculation) from some flowers, so that flower can supply no pollen of its own.
  2. Bag with muslin, so no pollen can arrive from outside. Muslin is used rather than polythene because air and light must still pass, otherwise you would be testing suffocation rather than pollination.
  3. Keep controls — a flower bagged with its stamens intact, and a flower left completely open. Without these you could not tell whether a failure was caused by the missing pollen or by the bag itself.
Why only one thing may be changed at a time: a fair test needs every other condition — same plant, same age of flower, same water, same sunlight, same day of counting — to be identical across the treatments. Then any difference in fruit formation can only be due to the one factor you altered, the availability of pollen. This is the logic that will reappear in exercise Questions 10 and 12.
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