Tag: internal structure of stem(dicot and monocot)

In dicot stem during secondary growth, the oldest part of xylem situated towards outer to the medulla and oldest phloem is situated just towards inner to the primary cortex.

So, the correct option is ‘Inner to primary cortex’.

A. Root – protoxylem is towards the pericycle and metaxylem is towards the medulla. It is called Exarch.

B. Stem – protoxylem is towards the medulla and metaxylem is towards the pericycle. It is called Endarch.

C. Leaves – the position of protoxylem and metaxylem is not specified.

D. Petiole – the position of protoxylem and metaxylem is not specified.

So, the correct option is ‘stem’.

Pericycle is the outer most part of the stele. In dicot, stem pericycle is, sclerenchymatous, discontinuous, multilayered and present in the form of patches over the vascular bundles.

So, the correct option is ‘Multilayered’.

In dicotyledonous trees, growing in temperate regions, due to maximum seasonal variations two types of secondary xylems are formed, spring or early wood and autumn wood or latewood. These two kinds of wood together form into a ring of wood called annual rings. These annual rings are useful in indicating the age of the trees.

So, the correct option is ‘Dicot of temperate regions’.

Cortex is middle region of the root and dicot stem, present between epidermis and stele.

So, the correct option is 'epidermis and stele'.

A.Vascular bundles arranged in a ring – found in T.s. of dicot stem

B.Scattered vascular bundles – found in T.s.of monocot stem

C.Closed vascular bundles – found in T.s.of monocot stem

D.Radial vascular bundles – found in T.s.of dicot and monocot roots.

So, the correct option is ‘Vascular bundles arranged in a ring’.

A. Conduction of water – xylem conducts water.

B.Storage of water – water storage parenchyma

C.Storage of food – cortex stores reserve food materials.

D. Strength – hypodermis and pericycle in dicot stem provides strength.

So, the correct option is ‘Storage of food’.

A.Pericycle – outer most part of the stele in roots and dicot stem.

B.Endodermis – innermost part of cortex in roots and dicot stem.

C. Cutinised – The outer walls of stem epidermal cells are cutinized i.e.covered by the cuticle.

D.Suberised – The walls of cork cells are suberized i.e. made up of suberin.

So, the correct option is ‘Endodermis’.

The large sized, slightly raised spots present on the surface of cork, in old dicot stems are called Lenticels. These are involved in the exchange of gases.

The small pores, present on the epidermis of grass leaves are called Hydathodes. In this guard cells are immovable. They perform guttation.

So, the correct option is ‘There is no regulation of their opening and closing’.

A.Apical meristem – meristem present in the apices of plant parts, found in all higher plants.

B.Primary meristem – meristem formed from embryonic tissues or promeristem. eg:Fascicular cambium – found in dicotyledons

C.Secondary meristem – meristem formed by the dedifferentiation of permanent tissues. eg:Inter fascicular cambium, cork cambium- found in dicotyledons

D.Intercalary meristem – meristem present in between permanent tissues, found in monocotyledons

So, the correct option is ‘Primary meristem’.