Test: Anatomy of Dicotyledonous & Monocotyledonous Plants - ACT MCQ

The ligno suberised thickenings present on the radial and tangential walls of the root endodermal cells are called Casparian bands or Casparian thickenings. Due to the presence of these thickenings, endodermis acts as a barrier for inflow of water and minerals and acts as a check point, prevents the outflow of water and minerals from the stele.
So, the correct option is 'Endodermis of the root'.

Intrafascicular cambium is present between xylem and phloem in dicot stem and roots. It is also termed as fascicular cambium. This meristematic area spreads laterally from each bundle and eventually becomes continuous, forming a complete vascular cambium.

Sieve tube elements are the only plant cells that do not have a nucleus at maturity. These unique cells are found in the phloem tissue and play a vital role in the transportation of organic substances like sugars from leaves to other parts of the plant.

In contrast, cambium cells, cells of pericycle, and xylem parenchyma all have nuclei. Cambium cells are meristematic cells that divide and differentiate into other cell types. Cells of pericycle are responsible for secondary growth in plants. Xylem parenchyma cells, part of the xylem tissue, store food and help in the sideways conduction of water. All of these cells need a nucleus to perform their functions.

In grasses, certain adaxial epidermal cells along the veins modify themselves into large, empty, colourless cells. These are called bulliform cells or motor cells. Bulliform cells help in folding and unfolding of grass leaves.

When the bulliform cells in the leaves have absorbed water and are turgid, the leaf surface is exposed. When they are flaccid due to water stress, they make the leaves curl inwards (inrolling) to minimise water loss (transpiration).

Lateral roots start to develop in the pericycle cells, which is the outermost cell layer in the vascular cylinder. Remember that the xylem and phloem make up the vascular cylinder and that it is found in the center of the root.