Tag: internal structure of stem(dicot and monocot)

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.

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.

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’.

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’.

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

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’

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

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’.

The corky outer layer of a plant is commonly called the periderm. It has three parts- the cork cambium (phellogen), the cork (phellem), and the secondary cortex (phelloderm). It usually forms as a result of secondary thickening in the case of an injury.

• In vascular plants, the secondary growth occurs due to the activity of the two lateral meristems- the cork cambium and the vascular cambium.
  
• In woody plants, the secondary growth produces wood and gives shapes to the plant with a thickened trunk.
• The secondary growth develops a cork cambium and vascular cambium.
• The cork cambium forms the thickened cork cells which protect the surface of the plant and also reduces water loss.
• Vascular cambium is also known as fascicular cambium which develops within the vascular bundles that produce xylem to the inner side and phloem to the outer side.
• In dicots, the fascicular and interfascicular cambium combine together to form a continuous ring called the vascular cambium.
• So, the correct answer is 'Lateral meristem'