Secondary Growth in Roots

The formation of cambium ring in dicot root is same as what we see in the dicot stem.

1. True

2. False

Secondary cortex is also known as______.

1. Bark.

2. Phellem

3. Phellogen

4. Phelloderm.

Secondary growth in dicot stem is possible because of the presence of

1. Xylem

2. Phloem

3. Cambium

4. Medullary rays

1. It is very similar to secondary growth in dicot stem
2. Pericycle cells above metaxylem become meristematic
3. A wavy ring of cambium is formed during the process
4. Cork cambium produces cork outside and secondary cortex inside

What is the fate of primary xylem in a dicot root showing extensive secondary growth?

(a) It is retained in the centre of the axis

(b) It gets crushed

(c) May or may not get crushed

(d) It gets surrounded by primary phloem

The cambium ring at the time of its origin in a dicot root

1. Is completely outside xylem and phloem.

2. Is completely inside xylem and phloem

3. Is internal to phloem and external to xylem.

4. Is external to phloem and internal to xylem.

Why do cells expand?

1. Rhizophora
2. Trope
3. Vanda
4. Asparagus

1. Arctic region
2. Grassland
3. Temperate region
4. All of the above

1. hypodermis
2. pericycle
3. epidermis
4. cortex

1. Position of proto xylem
2. Absence of secondary xylem
3. Absence of secondary phloem
4. Presence of cortex

1. Outer to endodermis and inner to primary cortex
2. External to primary cortex
3. Inner to endodermis and outer to pericycle
4. Inner to endodermis and external to primary phloem

What causes the formation of rings in dicots?

1. Secondary growth of xylem and phloem

2. Differential activity of cambium during different seasons

3. The differential growth of secondary xylem according to season

4. The differential growth of secondary phloem according to season

1. 3
2. 2
3. 4
4. 1

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

1. Reticulate thickening
2. Scalariform pitting
3. Oblique pitting
4. Intervascular pitting

1. It gets surrounded by primary phloem
2. It is retained in the centre of the axis
3. It gets crushed
4. May or may not get crushed

The cambium ring at the time of its origin in a dicot root

1. Is completely outside xylem and phloem.

2. Is completely inside xylem and phloem

3. Is internal to phloem and external to xylem.

4. Is external to phloem and internal to xylem.

1. Cork cambium
2. Vascular cambium
3. Xylem
4. Both a and b

1. Early wood is characterized by large number of xylary elements.
2. Early wood is characterized by vessels with wider cavities.
3. Late wood is characterized by large number of xylary elements.
4. Late wood is characterized by vessels with narrower cavities.

1. Only fascicular cambia
2. Only interfascicular cambia
3. Fascicular cambia and interfascicular cambia
4. Fascicular cambia and Phellogen

The periderm includes:

1. Secondary phloem
2. Cork
3. Cambium
4. All of these

1. a - Pore, b - Secondary cortex, c - Cork cambium, d - Cork, e - Complimentary cells
2. a - Pore, b - Cork cambium, c - Secondary cortex, d - Cork, e - Complimentary cells
3. a - Pore, b - Cork, c - Complimentary cells, d - Cork cambium, e - Secondary cortex
4. a - Pore, b - Complimentary cells, c - Cork, d - Cork cambium, e - Secondary cortex

1. Hypodermis
2. Epidermis
3. Pericycle
4. Cortex

1. Chronology
2. Dendrochronology
3. Ageing and development
4. None of the above

1. Epiphytes
2. Mesophytes
3. Hydrophytes
4. Xerophytes

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Why the roots of fern are known as adventitious roots inspite of having xylem and phloem in them ?