Tag: botany

Questions Related to botany

A typical monocotyledonous root is characterised by -

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Usually more than six xylem bundles

  2. Large and well developed pith

  3. No secondary growth

  4. All of these

Show answer
Correct Option: D
Explanation:
A typical monocotyledonous root can be characterized by: -
1) The xylem shows a polyarch condition where it forms numerous groups or bundles (usually 12 to 21).
2) The cambium is absent in all the stages and there is no secondary thickening in such roots.
3) The pith is large and well developed.
So, the correct answer is 'All of the above'.

Read the following statements :
(i). In monocot root, a large number of vascular bundles are arranged in the form of a ______ around the central ____
(ii). Due to the presence of _, the endodermal cells do not allow wall to wall movement of substances between cortex and pericycle, in a primary dicot root.
(iii). The epidermis of stem of sunflower bears several unbranched _____ hair.
(iv). The central portion of a dicot stem is usually occupied by ______ comprising of thin-walled parenchymatous cells
Select the option that correctly fills the blanks in any two of them.

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. (i) ring, pith; (ii) hypodermis

  2. (ii) Casparian strips; (iii) unicellular

  3. (i) ring, cortex; (iv) vascular bundles

  4. (iii) multicellular; (iv) pith

Show answer
Correct Option: D
Well developed pith is found in
botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Monocot root and monocot stem

  2. Monocot stem and dicot root

  3. Monocot root and dicot stem

  4. Dicot root and dicot stem

Show answer
Correct Option: C
Explanation:

Well developed pith or parenchymatous central region is present in monocot root (maize) and dicot stem (Sunflower). Its a structure of loosely arrannged cells that embeds vascular tissue, it may store food.

So, the correct answer is 'Monocot root and dicot stem'

Polyarch condition is found in

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Monocot root

  2. Dicot root

  3. Monocot stem

  4. Dicot stem

Show answer
Correct Option: A
Explanation:

Monocot root vascular bundles are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Xylem is described as exarch in monocot root. 

Monocot stem vascular bundles are conjoint, collateral and closed with endarch xylem. 
Dicot root vascular bundles are described as radial and tetrarch. There are four bundles each of xylem and phloem occurring alternately. Xylem is described as exarch. 
Dicot stem vascular bundles are eight in number, arranged in form of a broken ring. The vascular bundles are conjoint, collateral and open. Xylem is on the inner surface and phloem on the outer surface. Xylem is described as endarch. 

Passage cells are more distinct in endodermis of

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Dicot stem

  2. Monocot stem

  3. Dicot root

  4. Monocot root

Show answer
Correct Option: D
Explanation:

Passage cells are endodermal cells of older roots, which have retained thin walls and Casparian strips rather than becoming suberized and waterproof like the other cells around them, to continue to allow some symplastic flow to the inside. 

Passage cells function to allow transfer of solutes, such as calcium and magnesium into the stele, in order to eventually reach the transpiration system.
Passage cells are more distinct in endodermis of monocot root and absent in dicot root, monocot stem and dicot stem. Thus, option D is correct.

Polyarch and exarch condition of found in

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Monocot stem

  2. Monocot root

  3. Dicot stem

  4. Dicot root

Show answer
Correct Option: B
Explanation:

Monocot root vascular bundles are radial in arrangement. There are eight bundles each of xylem and phloem. Hence, the condition is described as polyarch. Xylem is described as exarch. 

Monocot stem vascular bundles are numerous in number and the xylem is endarch. 
Dicot stem vascular bundles  are eight in number, arranged in form of a broken ring. The vascular bundles are conjoint, collateral and open. Xylem is on the inner surface and phloem on the outer surface. Xylem is described as endarch. 
Dicot root vascular bundles are described as radial and tetrarch. There are four bundles each of xylem and phloem occurring alternately. Xylem is described as exarch. 

Eustele is characteristic of

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Monocots

  2. Dicots

  3. Pteridophytes

  4. Bryophytes

Show answer
Correct Option: B
Explanation:

Eustele - In this arrangement, the primary vascular tissue consists of vascular bundles, usually in one or two rings around the pith. In addition to being found in stems, the eustele appears in the roots of monocot flowering plants. The vascular bundles in a eustele can be collateral with the phloem on only one side of the xylem or bicollateral with phloem on both sides of the xylem, as in some Solanaceae. So, eustele is the characteristic of monocots and absent in dicots, pteridophytes and bryophytes. 
Thus, the correct answer is option A.

Two cross-sections of stem and root appear similar, when viewed by naked eye. But under microscope, they can be differentiated by

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Exarch condition of root and stem

  2. Endarch condition of stem and root

  3. Endarch condition of root and exarch condition stem

  4. Endarch condition of stem and exarch condition of root

Show answer
Correct Option: D
Explanation:

Endarch is the arrangement in which the protoxylem is directed towards the centre and metaxylem elements towards the periphery. The development of the xylems in this arrangement follows the centrifugal pattern. It is the characteristics of the stem of flowering plants. 

Whereas exarch is the arrangement in which the protoxylem is directed towards the periphery and metaxylem towards the centre. The development of the xylem in this arrangement follows the centripetal pattern. It is the characteristics of roots. Thus, option D is correct.

An example of monocot, fibre yielding plant is

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Cocos

  2. Corchorus

  3. Clematis

  4. Crotalaria

Show answer
Correct Option: A
Explanation:

Cocos nucifera, the coconut palm, is a monocot perennial member of the Arecaceae (palm family), cultivated in tropical areas worldwide for its fruit and fiber. Coir is a natural fibre extracted from the husk of coconut and used in products such as floor mats, doormats, brushes, mattresses, etc. Coir is the fibrous material found between the hard, internal shell and the outer coat of a coconut. Other uses of brown coir are in upholstery padding, sacking and horticulture. Thus, option A is correct. 

Centripetal xylem is found in

botany internal structure of root, stem and leaf internal structure of monocot root internal structure of root(dicot and monocot) anatomy of root

  1. Leaf

  2. Root

  3. Dicot stem

  4. Monocot stem

Show answer
Correct Option: B
Explanation:

Development of xylem from the periphery to the centre is called centripetal xylem. It is found in roots.

So, the correct option is ‘root’.