NCERT Solutions for Class 9th Science Chapter 11 Let us explore — Activity 11.5

Book page 214 – 215 Updated on2026-09-08

Q1.

Record the presence of various floral parts in the different flowers that you collected in Table 11.1.

Answer

Work outward to inward, one whorl at a time, and put a Yes or No against each part. The book has already filled in column A for you — Sepal Yes, Petal Yes, Stamen No, Pistil Yes — which tells you at once that flower A is a female (pistillate) flower, such as a papaya or a pumpkin female flower.

S. No.	Flower parts	A (as printed — a female flower)	B — hibiscus	C — mustard	D — maize male flower
1.	Sepal	Yes	Yes	Yes	No
2.	Petal	Yes	Yes	Yes	No
3.	Stamen	No	Yes	Yes	Yes
4.	Pistil	Yes	Yes	Yes	No

Why a flower can be missing a whorl: the four whorls develop independently, so a plant can leave one out. Where the male and female parts are in separate flowers — as in maize, papaya and pumpkin — self-pollination becomes impossible or difficult, and the plant is pushed towards cross-pollination and therefore towards more variation. Where petals are missing, as in the grasses, it is because the flower is wind-pollinated and has no use for them.

Tip: record the "Other feature(s)" column too — is the stigma sticky or feathery? are the petals fused into a tube? is the anther powdery? Those details are what let you predict the pollinating agent in Question 11 of the exercises.

Q2.

Analyse the function of each part of the flower based on visible characters.

Answer

Every visible character of a flower part points to the job it does. Read the structure and the function follows.

Part	What you can see	Function you can infer
Sepal	Green, thin, flat, tough; outermost; wraps the bud	Protects the bud; being green, it also photosynthesises
Petal	Coloured, large, often scented, nectar at the base	Attracts pollinators and rewards them with nectar
Stamen — filament	Thin stalk holding the anther out and up	Places the anther where a visiting insect or the wind will reach it
Stamen — anther	Swollen, powdery, yellow; powder rubs off on the finger	Produces the pollen grains, which carry the male gametes
Pistil — stigma	At the very top; flat, sticky and/or feathery	Catches and holds pollen; stickiness makes the pollen stay put
Pistil — style	Long thin tube connecting stigma to ovary	The path along which the pollen tube grows down to the ovule
Pistil — ovary	Swollen base; cut it open and small white ovules are inside	Holds the ovules, each containing an egg; later becomes the fruit

Why the stigma sits at the top of a long style: two reasons at once. Raised above the flower it is the first thing an arriving insect or a gust of wind touches, so it intercepts pollen efficiently. And the length of the style acts as a test — only a pollen grain of the right species can grow a tube all the way down it, so unsuitable pollen never reaches the ovule.

Q3.

Cut a transverse and a longitudinal section of the ovary (swollen base of the pistil) and observe it under a dissecting microscope. Draw a diagram of the structure you observed under the microscope.

Answer

Both cuts show the same thing from two directions — a hollow chamber with small white ovules attached to the inner wall by short stalks.

Longitudinal section (L.S.) — cut from the stigma down through the ovary. You see the ovary wall on both sides and a row of ovules standing along the inside, each on a short stalk. In a hibiscus or a pea the ovules are lined up one above the other.
Transverse section (T.S.) — cut across the ovary. You see the ovary in cross-section, divided by partitions into chambers (locules), with ovules in each chamber. A tomato ovary shows two to four chambers; a mustard ovary shows two; a pea pod shows one.

Why you should cut a fruit of the same plant next: the fruit is the ripened ovary and the seeds are the ripened ovules. So the number of chambers and the way the seeds are attached in a tomato fruit is exactly the number of chambers and the way the ovules are attached in a tomato ovary — just larger. Comparing the two, as the chapter's project work asks you to do, is a direct demonstration that the ovary becomes the fruit and the ovule becomes the seed.

Tip: the ovary of a small flower is only a few millimetres across. Use a fresh razor blade, cut with a single stroke rather than sawing, and put a drop of water on the section before looking at it. A jagged, dried-out cut shows nothing.

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