Pith cavity occurs in the stem of
- Helianthus
- Zea mays
- Cucurbita
- Dracaena
The Correct Option is C
Solution and Explanation
Top Questions on Secondary Growth
Identify the correct statements:
A. Lenticels are the lens-shaped openings permitting the exchange of gases.B. Bark formed early in the season is called hard bark.C. Bark is a technical term that refers to all tissues exterior to vascular cambium.D. Bark refers to periderm and secondary phloem.E. Phellogen is single-layered in thickness.Choose the correct answer from the options given below:
- NEET (UG) - 2023
- Biology
- Secondary Growth
- Match List - I with List - II.Choose the correct answer from the options given below.
List - 1 List - 1 a Lenticels i Phellogen b Cork cambium ii Suberin deposition c Secondary cortex iii Exchange of gases d Cork iv Phelioderm - NEET (UG) - 2021
- Biology
- Secondary Growth
- Secondary xylem and phloem in dicot stem are produced by
- NEET (UG) - 2018
- Biology
- Secondary Growth
- Plants having little or no secondary growth are
- NEET (UG) - 2018
- Biology
- Secondary Growth
- The vascular cambium normally gives rise to :
- NEET (UG) - 2017
- Biology
- Secondary Growth
Questions Asked in AIIMS exam
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : 02 is liberated in the non-cyclic photophosphorylation.
Reason (R) : Liberation of oxygen is due to photolysis of water.
In the light of the above statements, choose the correct answer from the options given below
- AIIMS - 2019
- Photosynthesis in higher plants
- Match the following column I with column II.
- AIIMS - 2019
- cloning
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : The Cro-Magnon man was the direct ancestor of the living modern man.
Reason (R) : Cro-Magnon man had slightly prognathous face.
In the light of the above statements, choose the correct answer from the options given below
- AIIMS - 2019
- evolution
- Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion: Orbit of a satellite is within the gravitational field of earth whereas escaping is beyond the gravitational field of earth.
Reason: Orbital velocity of a satellite is greater than its escape velocity.
In the light of the above statements, choose the correct answer from the options given below- AIIMS - 2019
- Gravitation
Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion (A) : In eukaryotes, transcription occurs in nucleus.
Reason (R) : In bacteria, transcription and translation occurs in cytoplasm.
In the light of the above statements, choose the correct answer from the options given below
- AIIMS - 2019
- Transcription
Concepts Used:
Secondary Growth
Secondary growth is an increase in girth of thickness of the axis due to activity of lateral meristem. The tissues involved in secondary growth are two lateral meristems are vascular cambium and cork cambium.
Secondary Growth in Stem:
Formation of Cambium Ring-
- The cambium present between the xylem and phloem in vascular bundles is called Fascicular or Interfascicular cambium.
- In secondary growth, few medullary ray cells that are located between vascular bundles also become meristematic, and it is known as Interfascicular cambium.
Formation of the secondary tissues-
- The cambium ring cuts off cells on both sides. It produces secondary phloem outwardly and secondary xylem inwardly.
- The amount of secondary xylem cut off is more than the secondary phloem.
Secondary Growth in Root:
Vascular Cambium-
- The cambium is absent initially but develops later at the time of secondary growth.
- The pericycle cells lying outside the protoxylem and the conjunctive parenchyma cells on the lateral side of the phloem bundle become meristematic to form many cambial strips.
Cork Cambium-
- The cork cambium develops because of the tangential division of cells of the pericycle.
- The activity of cork cambium is like that found in the dicot stem, so it produces cork cells or phellem towards the outside and phelloderm or secondary cortex towards the inside.
Abnormal secondary growth:
- Due to absence of the cambium in monocots, monocots don’t show secondary growth and the vascular system is totally composed of primary tissues.
- The vascular bundles are irregularly scattered in the ground tissues, such that the cortex and other ground tissues can’t be differentiated.
- Dracaena, Yucca, Agave are examples of monocots that exhibit a peculiar type of secondary growth in thickness.