Tag: botany

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

In dicot root showing secondary growth, cork is found

  1. External to primary cortex

  2. Inner to epidermis and outer to pericycle

  3. Outer to endodermis and inner to primary cortex

  4. Inner to endodermis and external to primary phloem
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During secondary growth, rupturing of epidermal cell and outer cortex by secondary tissues induces formation of new protective layer, periderm turning the single layered pericycle into multi layered meristem that divides to form cork cambium or phellogen. The cork cambium exhibit meristematic activity and produces cork or phellem towards the periphery and phelloderm on inside, i.e., extrastellar growth. Moving from centre to periphery, a dicot root has pith, secondary xylem, secondary phloem, phelloderm (secondary cortex), phellogen (cork cambium), cork (phellem) and bark. Since, primary cortex is ruptured and is not present in secondary root. Cork is extra stellar tissues which is present outside the stele (vascular bundle, pith and medullary rays surrounded by pericycle) region and hence, cannot be present inner to endodermis.
Thus, the correct answer is option B.

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

Vascular bundles occur in a ring in

  1. Monocot stem

  2. Leaf

  3. Root

  4. Dicot stem
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
 In the dicot stem, the vascular bundles are arranged in a ring, with pith concentrated at the core of the stem, rather than being scattered throughout the plant interior. In dicot stem wedgw shaped, definite and arranged in one or two rings. Vascular bundles are conjoint, collateral and open.
Multiple choice botany internal structure of root, stem and leaf internal structure of dicot stem internal structure of stem(dicot and monocot) anatomy of stem

Well developed pith is found in

  1. Monocot stem and dicot root

  2. Monocot and dicot stems

  3. Dicot stem and dicot root

  4. Dicot stem and monocot root
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The parenchyma in the centre is called as the pith. The term stele included the vascular system, associated tissues and the pith. The protostele is a simple, unbranched, centrally located axial strand of xylem interspersed with phloem. A protostele contains no pith. It is generally found in dicot stems and in most angiosperm monocot roots.

Thus, the correct answer is option D.

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

Collenchyma generally occurs

  1. Scattered in dicot roots

  2. In a ring in monocot roots

  3. In patches under epidermis in dicot stem

  4. In all of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The hypodermis is found below the epidermis in dicot stem and is constituted with angular collenchyma which is 3-5 layered. Pericycle consists of alternately arranged patches of sclerenchyma and parenchyma. 
Thus, the correct answer is option C.

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

The outer cellular complex present on the outside of those stems and roots which have undergone secondary growth is?

  1. Periderm

  2. Epiblema

  3. Phelloderm

  4. Phellogen
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A. Periderm - During secondary growth in both dicot stem and root, multilayered or cellular complex tissue formed in the region of cortex is called Periderm. It is formed towards the outer side of the stem or root.

B.Epiblema – Epidermis with root hairs is called Epiblema.

C. Phelloderm – the parenchymatous formed towards inner side of the cork cambium is called phelloderm or secondary cortex.

D. Phellogen – a ring of meristematic tissue formed by the dedifferentiation of parenchyma present in the general cortex of dicot stem or root is called Phellogen or cork cambium.

So, the correct option is ‘Periderm’.

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

Number of cambial strips in a vascular bundle of Cucurbita stem is?

  1. $1$
  2. $2$
  3. $3$
  4. $4$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In the vascular bundles of Cucurbita stems, a xylem strand and two phloem strands are present on the same radius. So the vascular bundles are called Bicollateral vascular bundles. In these bundles, two strips of cambiua are present in between the xylem and phloem.

So, the correct option is ‘ 2’.

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

In an old stem, the oldest secondary xylem is found just

  1. Inner to vascular cambium

  2. Outside primary xylem

  3. Outside vascular cambium

  4. Inner to phellogen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In dicot stem, during secondary growth, when new secondary xylem formation is going on, oldest secondary xylem appear outside the primary xylem.

So, the correct option is 'Outside primary xylem.

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

Bundle sheath is absent around vascular bundles of.

  1. Dicot stem

  2. Monocot stem

  3. Dicot leaf

  4. Monocot leaf
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The layer with thick walled present around the vascular bundles is called Bundle sheath. It is sclerenchymatous in monocot stem vascular bundles, parenchymatous in dicot leaf and monocot leaf. It is absent in vascular bundles of dicot stem

So, the correct answer is ‘Dicot stem’

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

A dicot in which stem has scattered vascular bundles is

  1. Helianthus

  2. Pepromia

  3. Yucca

  4. Dolichos
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A.Helianthus - a dicot with rings of vascular bundles in the stele. It is called Eustele.

B.Peperomia - a dicot with scattered vascular bundles in the stele. It is called atactostele.
C.Yucca - a monocot with scattered vascular bundles in the stele. It is called Atactostele.
D.Dolichos - a dicot with rings of vascular bundles in the stele. It is called Eustele.
So, the correct option is 'Peperomia'.

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

Endodermis of dicot stem is also called

  1. Bundle sheath

  2. Starch sheath

  3. Mesophyll

  4. Water channel
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In dicot stem, endodermal cells are rich in starch grains. So it is also called endodermoid layer or starch sheath or starch layer.

So, the correct option is ‘Starch sheath’.