Tag: botany
Questions Related to botany
Two cross-sections of stem and root appear simple, when viewed by naked eye. But under microscope, they can be differentiated by
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Exarch condition of root and stem
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Endarch condition of stem and root
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Endarch condition of root and exarch condition of stem
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Endarch condition of stem and exarch condition of root
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.
In dicot stems, vascular cambium is formed from ________.
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Procambium
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Cambium
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Promeristem
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Protoderm
- The vascular cambium makes up the growth layer in the stems and roots of many plants (in dicots- buttercups etc)
- They are unspecialized cylindrical meristematic cells that divide to form secondary vascular tissues.
- The vascular cambium is derived from the procambium which is present in the vascular bundles and the interfascicular parenchyma cells which are present between the vascular bundles
- So, the correct answer is 'Procambium'
Oldest part of phloem in a dicot stem is situated just.
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Outside vascular cambium
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Inner to primary cortex
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Inner to vascular cambium
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Between periderm and primary cortex
In dicot stem during secondary growth, the oldest part of xylem situated towards outer to the medulla and oldest phloem is situated just towards inner to the primary cortex.
So, the correct option is ‘Inner to primary cortex’.
The endarch condition is characteristic of
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Root
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Stem
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Leaves
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Petiole
A. Root – protoxylem is towards the pericycle and metaxylem is towards the medulla. It is called Exarch.
B. Stem – protoxylem is towards the medulla and metaxylem is towards the pericycle. It is called Endarch.
C. Leaves – the position of protoxylem and metaxylem is not specified.
D. Petiole – the position of protoxylem and metaxylem is not specified.
So, the correct option is ‘stem’.
In dicot stem, the pericycle is?
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Single layered
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Multilayered
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Two layered
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Absent
Pericycle is the outer most part of the stele. In dicot, stem pericycle is, sclerenchymatous, discontinuous, multilayered and present in the form of patches over the vascular bundles.
So, the correct option is ‘Multilayered’.
Annual rings can be useful for indicating age of the tree
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Dicot of equatorial region
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Monocot of equatorial region
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Dicot of temperate region
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Monocot of temperate area
In dicotyledonous trees, growing in temperate regions, due to maximum seasonal variations two types of secondary xylems are formed, spring or early wood and autumn wood or latewood. These two kinds of wood together form into a ring of wood called annual rings. These annual rings are useful in indicating the age of the trees.
So, the correct option is ‘Dicot of temperate regions’.
Cortex lies between
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Epidermis and endodermis
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Endodermis and pith
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Hypodermis and endodermis
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Epidermis and stele
Cortex is middle region of the root and dicot stem, present between epidermis and stele.
So, the correct option is 'epidermis and stele'.
A T.S. of dicot stem shows
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Vascular bundles arranged in a ring
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Scattered vascular bundles
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Closed vascular bundles
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Radial vascular bundles
A.Vascular bundles arranged in a ring – found in T.s. of dicot stem
B.Scattered vascular bundles – found in T.s.of monocot stem
C.Closed vascular bundles – found in T.s.of monocot stem
D.Radial vascular bundles – found in T.s.of dicot and monocot roots.
So, the correct option is ‘Vascular bundles arranged in a ring’.
Major function of cortex is?
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Conduction of water
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Storage of water
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Storage of food
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Strength
A. Conduction of water – xylem conducts water.
B.Storage of water – water storage parenchyma
C.Storage of food – cortex stores reserve food materials.
D. Strength – hypodermis and pericycle in dicot stem provides strength.
So, the correct option is ‘Storage of food’.
Inner-most layer of cortex is
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Pericycle
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Endodermis
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Cutinised
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Suberised
A.Pericycle – outer most part of the stele in roots and dicot stem.
B.Endodermis – innermost part of cortex in roots and dicot stem.
C. Cutinised – The outer walls of stem epidermal cells are cutinized i.e.covered by the cuticle.
D.Suberised – The walls of cork cells are suberized i.e. made up of suberin.
So, the correct option is ‘Endodermis’.