Tag: shoot and root apex

Questions Related to shoot and root apex

Histogen theory was proposed by

  1. Nageli

  2. Schmidt

  3. Hanstein

  4. Wolf


Correct Option: C
Explanation:
  • The shoot apical meristems located at the shoot tip in plants are derived from the apical meristematic tissues according to the histogen theory given by Hanstein in 1868.
  • It consists of three distinct layers:-
1) Dermatogen is the primary meristem that forms the outer most layer of a plant or a plant part and forms the epidermis.
2) Periblem is a primary meristem which is located between the plerome and the dermatogen and it forms the cortex.
3) Plerome is the primary meristem that forms the central core of a plant or plant part which gives rise to the stele (includes the vascular tissue, pith and pericycle).
  • The part of plerome from which vascular tissues are formed is called procambium.
So, the correct answer is 'Hanstein'

According to the concept of waiting meristem, the active region of shoot apex is?

  1. Anneau initial

  2. Meristeme medullaire

  3. Promeristeme sporogene

  4. Promeristeme receptaculaire


Correct Option: A

Match List-I(Region) with List-II(Contribution to) and select the correct answer using the codes given the lists.

List-I(Region) List-II(Contribution)
a. Apical cells of $2$-celled embryo $1$. Emergence of cotyledons
b. Basal cells of $2$-celled embryo $2$. Differentiation of root and shoot
c. Torpedo stage embryo $3$. Root apex and suspensor
d. Globular embryo $4$. Bulk of the embryo proper
  1. A-$1$, B-$2$, C-$3$, D-$4$

  2. A-$1$, B-$3$, C-$2$, D-$4$

  3. A-$4$, B-$2$, C-$4$, D-$1$

  4. A-$4$, B-$3$, C-$2$, D-$1$


Correct Option: A

Consider the following statements.
a. In the roots with endomycorrhizal association, the fungal hyphae penetrate the root cortex and pass through the casparian strip to enter vascular tissue.
b. The globin part of leghemoglobin in nitrogen-fixing root nodules is encoded by the bacterium whereas heme group is synthesized by the host plant.
Which of the statements given is/are correct?

  1. $1$ only

  2. $2$ only

  3. Both $1$ and $2$

  4. Neither $1$ nor $2$


Correct Option: A

Choose the correct answers from the alternatives given.
Which of the following functions is not shared by both the root system and the shoot system of a plant?

  1. Absorb water

  2. Transport water

  3. Transport inorganic nutrients

  4. Transport organic nutrients


Correct Option: A
Explanation:

The root system forms the underground system of the plant that absorbs water from the soil along with various organic and inorganic nutrients. It exerts the root pressure due to which the absorbed water is transported to the shoot system.

The shoot system forms the upper part of the plant part. It transports the absorbed water and nutrients to different plant parts.
Hence, the correct answer is 'Absorb water'.

Which one of the following histogens is present in the roots but Not in the shoots?

  1. Calyptrogen

  2. Dermatogen

  3. Periblem

  4. Plerome


Correct Option: A
The cells of the quiescent centre are characterised by
  1. having dense cytoplasm and prominent nuclei

  2. having light cytoplasm and small nuclei

  3. dividing regularly to add to the corpus

  4. dividing regularly to add to tunica


Correct Option: B
Explanation:

The cells of the quiescent centre are characterised by 'light cytoplasm and small nuclei'.

Choose the correct answers from the alternatives given :
Plant roots function to

  1. anchor the plant

  2. store the products of photosynthesis

  3. produce hormones that stimulate stem growth

  4. all of the above


Correct Option: D
Explanation:

Root is the most important organ of a plant which generally lies below the soil in the vascular plants.

The main functions of the root are:
a. It anchors the plants in soil and thus provides mechanical support to plants to stand upright.
b. Photosynthesis products are usually stored in roots. eg. Raddish, carrots etc.
c. Roots synthesize certain hormone that helps in the growth of the plant.

So the correct answer is "All of the above"

Choose the correct answers from the alternatives given.
When a leaf trace extends from a vascular bundle in a dicot stem, what would be the arrangement of vascular tissues in the veins of the leaf

  1. Xylem would be on top and the phloem on the bottom

  2. Phloem would be on top and the xylem on the bottom

  3. Xylem would encircle the phloem

  4. Phloem would encircle the xylem


Correct Option: A
Explanation:

Vascular bundles are scattered in the spongy parenchyma. These can be seen in the veins and the midrib of the leaves. The dicot leaves possess reticulate venation in which veins form a network. The xylem forms the top layer and phloem is present at the bottom in the arrangement of the vascular tissues. The veins vary in thickness in the reticulate venation.

Hence, the correct answer is 'Xylem would be on top and the phloem on the bottom'.