Plant and Animal Tissues — Important Questions

Parenchyma

Step 1: Parenchyma is a type of simple permanent supporting tissue. Step 2: It is composed of large, thin-walled living cells with intercellular spaces. Step 3: One of its main functions is to store food material – for example, potatoes are mainly made of parenchyma cells that store starch. Step 4: Collenchyma provides flexible support; sclerenchyma provides rigid support; xylem transports water. Step 5: Parenchyma is found in the soft parts of plants, including leaves, pith of stems, and roots.

Providing rigid strength and support to the plant

Step 1: Sclerenchyma is a type of simple permanent tissue. Step 2: It is made of long, narrow, and thick-walled cells that are dead at maturity. Step 3: Because the cells are dead and thick-walled, they provide rigid (hard) mechanical and structural support to the plant. Step 4: Sclerenchyma is found in stems and veins of leaves, mostly as fibres. Step 5: Photosynthesis is done by parenchyma (with chloroplasts); transport of water is done by xylem; flexible support is the function of collenchyma.

Xylem

Step 1: Complex permanent tissues are also called vascular or conducting tissues. Step 2: There are two types – xylem and phloem. Step 3: Xylem is formed of thick-walled, tubular, often dead cells placed end to end. Step 4: Xylem transports water and minerals absorbed by the roots upward to the leaves – this is unidirectional (only upward). Step 5: Phloem transports food (not water); collenchyma and parenchyma are simple permanent tissues, not conducting tissues.

Both upward and downward (bidirectional)

Step 1: Phloem is a complex permanent tissue that transports food. Step 2: Food is manufactured in the leaves through photosynthesis. Step 3: This food needs to reach all parts of the plant – both above and below the leaves. Step 4: Therefore, phloem conducts food in both upward and downward directions – this is called bidirectional transport. Step 5: Xylem, in contrast, transports water only upward (unidirectional). Options A and B describe only one direction, which is incomplete.