NCERT Solutions for Class 9th Science Chapter 11 Let us investigate — Activity 11.6

Book page 215 – 216 Updated on2026-09-08

Q1.

In which treatment(s) do you find the flowers are replaced by fruits?

Answer

Fruits form in every treatment except one — the bud whose stamens were removed and which was then bagged.

Treatment	Could pollen reach the stigma?	Fruit formation (Yes/No)
Flower bud (bagged, stamens intact)	Yes — its own pollen, inside the closed bud	Yes
Flower bud with stamens removed (bagged)	No — no pollen inside, none can enter	No
Flower with stamens removed (bagged)	Yes — it had already pollinated itself while still a bud	Yes
Flower (bagged, stamens intact)	Yes — its own pollen	Yes
Flower without bag	Yes — its own pollen, and visitors could also come	Yes

Why removing the stamens from an open flower is too late: in pea, the petals form a closed keel and the anthers shed their pollen straight onto the stigma while the flower is still a bud. By the time the flower blooms, it has already been pollinated. So the third treatment still gives a pod. Only in a juvenile bud, before the anthers have opened, does removing the stamens actually take the pollen away — and only that treatment fails to give a fruit. The pattern of results is not an accident of the experiment; it is a direct fingerprint of how a pea flower pollinates itself.

Tip: this is why plant breeders emasculate flowers in the bud stage when they want to make a controlled cross. Wait for the flower to open and the plant has already done the job for itself.

Q2.

What can we infer from this activity?

Answer

That the transfer of pollen grains from the anther to the stigma — pollination — is necessary before a fruit can form. Take the pollen away and no fruit appears; leave it, whether the flower is bagged or open, and a fruit does.

Two further conclusions follow from the same table:

The bag itself does not stop fruiting. The bagged flower with stamens intact fruited just as well as the open one, so muslin bagging is not what caused the failure in the emasculated bud.
Pea is normally self-pollinated, and self-pollination happens in the bud. That is the only way an emasculated open flower could still make a pod.

Why pollination alone is not the whole story: pollination only delivers the pollen to the stigma. What actually starts the fruit is what follows — the grain germinates, grows a pollen tube down the style, and the male gamete fuses with the egg cell in the ovule. That fusion is fertilisation. Only then does the ovary begin to enlarge into a fruit and the ovules into seeds. Pollination is the necessary first step, not the finished process.

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