Dicotyledonous Stem

Question 1

What is the outermost protective layer of the dicot stem?

Answer 1

Epidermis.

Question 2

What are two features that the dicot stem epidermis may bear?

Answer 2

Trichomes and a few stomata.

Question 3

Where is the cortex located in a dicot stem?

Answer 3

Between the epidermis and the pericycle.

Question 3

What is the epidermis of a dicot stem covered with?

Answer 3

A thin layer of cuticle.

Question 4

What are the three sub-zones of the dicot stem cortex?

Answer 4

1. Hypodermis [outer]
2. Cortical layers [middle]
3. Endodermis. [inner]

Question 5

Describe the hypodermis of a dicot stem.

Answer 5

A few layers of collenchymatous cells just below the epidermis.

Question 6

What is the function of the hypodermis?

Answer 6

To provide mechanical strength to the young stem.

Question 7

Describe the cortical layers below the hypodermis.

Answer 7

Rounded, thin-walled parenchymatous cells with conspicuous intercellular spaces.

Question 8

What is the endodermis of a dicot stem also called

Answer 8

starch sheath

Question 9

Why is the endodermis of a dicot stem also called the “starch sheath”?

Answer 9

Because its cells are rich in starch grains.

Question 10

Where is the pericycle located in a dicot stem?

Answer 10

On the inner side of the endodermis and above the phloem.

Question 11

In what form is the pericycle found in a dicot stem?

Answer 11

As semi-lunar patches of sclerenchyma.

Question 12

What are “medullary rays”?

Answer 12

Radially placed parenchymatous cells found in between the vascular bundles.

Question 13

What is the characteristic arrangement of vascular bundles in a dicot stem?

Answer 13

They are arranged in a ring.

Question 14

What are the three structural characteristics of a dicot stem vascular bundle?

Answer 14

Conjoint, open, and with endarch protoxylem.

Question 15

What constitutes the pith in a dicot stem?

Answer 15

A large number of rounded, parenchymatous cells with large intercellular spaces.

Question 16

Where is the pith located in the stem?

Answer 16

It occupies the central portion of the stem.