NCERT Solutions for Class 9th Science Chapter 12 Pteridophyta — In-text Questions
Book page 238 Updated on2026-09-19
Q1.
Look at Fig. 12.11a. What changes do you observe in the plant structure as compared to thallophytes and bryophytes?
Fig. 12.11a, page 238 — redrawn sketch of the textbook photograph of a fern. Unlike a thallophyte or a bryophyte, the fern has true roots, a true stem and true leaves; the young fronds are still coiled up.
Answer
The fern in Fig. 12.11a has, for the first time in the plant kingdom, true roots, a true stem and true leaves. Thallophytes had none of these — only a thallus, an undifferentiated body. Bryophytes had rhizoids and merely stem-like and leaf-like structures. The fern has the real organs.
Thallophyta
Bryophyta
Pteridophyta
Body
Thallus — undifferentiated
Slight differentiation of parts
True roots, stems and leaves
Anchorage
None / holdfast
Rhizoids
True roots that absorb
Vascular tissue
Absent
Absent
Xylem and phloem present
Height possible
Very small, water-supported
A few centimetres
Up to metres — tree ferns exist
Water needed for reproduction
Yes
Yes
Yes — still
Seeds
No
No
No
Why the change is so large: a plant with true roots can pull water from soil that is deeper than its own body, and a plant with a stiff stem can hold its leaves above its neighbours. Neither is possible without a pipe system to move the water up. So the visible change in shape — a taller, upright, divided plant — is really the outward sign of a hidden change: the arrival of vascular tissue.
Q2.
How do you think that the transport of water and food takes place in all parts of these plants?
Answer
Through specialised transport tissue running from root to leaf tip — xylem carrying water upward and phloem carrying food. This is the "one possible explanation" the chapter offers, and it is the correct one.
Why some such tissue is needed at all: in a moss, every cell is within a fraction of a millimetre of the outside, so water reaches it by diffusion. A fern frond may stand 30 cm or more above the soil. Diffusion over that distance is hopelessly slow — the same surface-area-to-volume problem that forces animals to grow blood vessels. A plant that grows tall must therefore build pipes.
What the two tissues do:
Xylem — hollow, dead, thick-walled tubes joined end to end. It carries water and dissolved minerals from the roots upwards, and its lignified walls also stiffen the stem, which is what allows the plant to stand up.
Phloem — living tubes that carry food made in the leaves to every other part, including downwards to the roots, which cannot photosynthesise.
Connect it back: the fern's problem is exactly the problem the animal kingdom keeps meeting later in this chapter. A sponge lets water flow through pores to reach every cell; a bigger animal must build a circulatory system instead. Transport tissue is the plant's version of the same solution.
Q3.
How can you test this explanation?
Answer
Cut a thin cross section of a fern stem and look at it under a microscope. If the explanation is right, the cut surface must show the pipes; if the fern had no transport tissue, the section would be uniform.
Method:
Take a fresh fern stem (rhizome or frond stalk) and cut a very thin transverse slice with a sharp blade — thin enough for light to pass through.
Mount it in a drop of water on a slide, add a coverslip, and examine under the low and then high power of a compound microscope. A permanent slide of a fern stem cross section from the school laboratory works equally well.
Look for groups of thick-walled tubes arranged in bundles.
What you find: Fig. 12.11b shows the result — the cross section carries vascular tissues, xylem and phloem, which transport water and food respectively throughout the plant. The prediction is confirmed.
Why this counts as a test: the explanation made a specific, checkable claim about a structure that had not yet been observed. Looking at the section could have refuted it — a uniform mass of similar cells would have shown the explanation was wrong. That is what makes it a test rather than a demonstration. Making a prediction, then looking, is the whole method the chapter uses again in Activity 12.7.