Primary Structure of Plant

Question 1

What is growth?

Answer 1

Growth involves the irreversible increase of dry mass associated with an organism’s development

Question 2

What type of growth do plants undergo

Answer 2

Plants continue growth throughout life and is known as indeterminate growth

Question 3

Describe the primary structure of a root

Answer 3

• Apart from the distribution pattern of xylem and phloem tissue, structures of both monocot and dicot roots are more or less similar.
• The outermost cell layer is epidermis. Some epidermal cells produce finger-like extensions called root hairs
• Epidermis protects the inner parts while root hairs involve in absorption of water and minerals
• Between the epidermis and vascular cylinder, there’s a ground tissue known as the cortex. It is mainly made out of parenchyma cells with intercellular spaces.
• The cortex mainly stores carbohydrates, and transports water and minerals towards the endodermis.
• The innermost single cell layer of the cortex is endodermis.
• Endodermis contains a suberin belt called casparian strip and no intercellular spaces. So, it blocks the cortical apoplast from the vascular apoplast.
• Interior to endodermis, there’s a pericycle containing 2 or 3 parenchyma cell layers. These cells in dicot roots have a meristematic function and involve in the formation of lateral roots, and secondary growth of the root
• Pericycle of monocot roots is not meristematic.
• Inner to the pericycle, there’s vascular tissues as a solid core.
• In dicot roots, xylem can be found in the middle and it’s star shaped in a cross section. Phloem is found in the groove between the arms of xylem.
• In monocot roots, vascular tissue consists of a central core of parenchyma cells surrounded by a ring of alternating xylem and phloem

Question 4

What is the outermost cell layer of the root?

Answer 4

Epidermis

Question 5

What are root hairs?

Answer 5

Some epidermal cells produce finger-like extensions called root hairs

Question 6

What’s the function of epidermis in root?

Answer 6

Protecting the inner parts

Question 7

What’s the function of root hairs in root?

Answer 7

Involve in absorption of water and minerals

Question 8

Where is the cortex located?

Answer 8

Between the epidermis and vascular cylinder

Question 9

Describe the structure of cortex of root

Answer 9

It is made of mostly parenchyma cells with intercellular spaces

Question 10

What is the function of cortex in root?

Answer 10

Storing carbohydrates

Transporting water and minerals towards the endodermis

Question 11

What is the endodermis?

Answer 11

The innermost single cell layer of the cortex

Question 12

What is the casparian strip?

Answer 12

Endodermis contains a suberin belt called casparian strip with no intercellular spaces. Therefore, it blocks cortical apoplast from vascular apoplast

Question 13

What’s the function of casparian strip?

Answer 13

blocking cortical apoplast from vascular apoplast

Question 14

Where is the pericycle located?

Answer 14

Inner to endodermis

Question 15

What is pericycle made of?

Answer 15

2 or 3 parenchyma cell layers

Question 16

What is the function of the parenchyma cells of the pericycle of dicot roots?

Answer 16

These cells in dicot roots have a meristematic function and involve in the formation of lateral roots and secondary growth of the root

Question 17

Is the pericycle in monocot roots meristematic?

Answer 17

No

Question 18

Where is the solid core made of vascular tissues found?

Answer 18

Inner to the pericycle

Question 19

Describe the arrangement of vascular tissues in the core of dicot root

Answer 19

In dicot roots, xylem can be found in the middle and it’s star shaped in a cross-section.

Phloem is located in the groove between the arms of xylem

Question 20

What is the core of monocot roots shaped like?

Answer 20

In monocot roots, vascular tissue consists of a central core of parenchyma cells surrounded by a ring of alternating xylem and phloem

Question 21

What are the differences between dicot root and monocot root?

Answer 21

• Dicot cortex is greater in width.
• Pericycle of dicot roots have a meristematic function at secondary growth. Pericycle of monocot roots is not meristematic.
• In dicot roots, xylem can be found in the middle and it’s star shaped in a cross-section. Phloem is located in the groove between the arms of xylem. In monocot roots, vascular tissue consists of a central core of parenchyma cells surrounded by a ring of alternating xylem and phloem
• In dicot roots, 4 xylem bundles are present. In monocot roots, the no. of xylem bundles is higher than 4
• No pith is present in dicot roots. Pith is present in monocot roots

Question 22

What are the differences of dicot and monocot root regarding the cortex?

Answer 22

Dicot cortex is greater in width.

Question 23

What are the differences of dicot and monocot root regarding the pericycle?

Answer 23

Pericycle of dicot roots have a meristematic function at secondary growth. Pericycle of monocot roots is not meristematic.

Question 24

What are the differences of dicot and monocot root in vascular tissue?

Answer 24

In dicot roots, xylem can be found in the middle and it’s star shaped in a cross-section. Phloem is located in the groove between the arms of xylem. In monocot roots, vascular tissue consists of a central core of parenchyma cells surrounded by a ring of alternating xylem and phloem

In dicot roots, 4 xylem bundles are present. In monocot roots, the no. of xylem bundles is higher than 4

Question 25

What are the differences of dicot and monocot root in pith?

Answer 25

No pith is present in dicot roots. Pith is present in monocot roots

Question 26

Describe the primary structure of a dicot plant stem

Answer 26

• The outermost epidermal cell layer protects the inner parts from desiccations and infections
• The epidermis is interrupted by pores called stomata
• Interior to the epidermis, is cortex, mostly containing parenchyma cells
• Collenchyma cells may also be present just beneath the epidermis, to provide strength
• Sclerenchyma (such as fibers) are also present in the cortex to provide additional support
• Vascular bundles are arranged in a ring
• A vascular bundle contains primary phloem towards the cortex, primary xylem towards the pith and a cambium tissue inbetween.
• Outside vascular bundle, there’s a cluster of sclerenchyma cells
• Inner to vascular bundles, a large pith which is also made of parenchyma cells can be found
• Lateral shoots develop from auxiliary buds

Question 27

What’s the function of the epidermis of the plant stem?

Answer 27

Protecting the inner parts of the stem from desiccation and infection

Question 28

What are the pores the epidermis of the stem is interrupted by?

Answer 28

Stomata

Question 29

What is the cortex of the stem made of?

Answer 29

Mostly parenchyma cells

Question 30

Where can sclerenchyma cells be found in the plant stem?

Answer 30

Just beneath the epidermis

Question 31

What’s the function of collenchyma cells in the plant stem’s cortex?

Answer 31

To provide strength

Question 32

What is the function of sclerenchyma cells in the cortex?

Answer 32

To provide additional support

Question 33

What are the different types of cells found in the stem’s primary structure?

Answer 33

• Interior to the epidermis, is cortex, mostly containing parenchyma cells
• Collenchyma cells may also be present just beneath the epidermis, to provide strength
• Sclerenchyma (such as fibers) are also present in the cortex to provide additional support

Question 34

Describe the nature of vascular bundles in the dicot plant stem

Answer 34

• Vascular bundles are arranged in a ring
• A vascular bundle contains primary phloem towards the cortex, primary xylem towards the pith and a cambium tissue in-between.
• Outside vascular bundle, there’s a cluster of sclerenchyma cells
• Inner to vascular bundles, a large pith which is also made of parenchyma cells can be found

Question 35

Where can parenchyma cells be found in the dicot plant stem?

Answer 35

Cortex and Pith

Question 36

Where do lateral shoots develop from?

Answer 36

Auxiliary buds

Question 37

Describe the primary structure of a monocot stem

Answer 37

• The outermost epidermal cell layer protects the inner parts from desiccations and infections
• The epidermis is interrupted by pores called stomata
• Ground tissue of monocot stem isn’t differentiated to cortex and pith
• Sclerenchyma (such as fibers) are also present to provide additional support
• The vascular bundles are scattered throughout the ground tissue in most monocot stems
• Each vascular bundle is surrounded by sclerenchyma. It consists of a xylem tissue and phloem tissue but no cambium in-between xylem and phloem
• Lateral shoots develop from auxiliary buds

Question 38

What are the special characteristics of the primary structure of the monocot stem?

Answer 38

• Ground tissue of monocot stem isn’t differentiated to cortex and pith
• The vascular bundles are scattered throughout the ground tissue in most monocot stems
• Each vascular bundle is surrounded by sclerenchyma. It consists of a xylem tissue and phloem tissue but no cambium in-between xylem and phloem

Question 39

What are the differences between the monocot stem and dicot stem?

Answer 39

Ground tissue of dicots is differentiated to cortex and pith. In monocot stem, ground tissue isn’t differentiated to cortex and pith.

In dicot stem cortex contains sclerenchyma and collenchyma. In monocot stem, it may contain a few sclerenchyma cells

Vascular bundles are arranged in a ring in dicot stem. Vascular bundles are of the same size, and there’s only a few.

In monocot stems, there are more vascular bundles scattered all over the cortex. They are not of the same size, smaller near the epidermis and larger as they get closer to cortex.

In dicot stem, cambium is present. In monocot stem, cambium is absent

In monocot stem, xylem arranged in V-shape. Lysogenic cavity is absent. In monocot stem, lysogenic cavity is present