Anatomy of Flowering Plants Test - 86

A.Cork cambium(phellogen) – a ring of meristematic tissue formed by the dedifferentiation of parenchyma present in the cortex of dicot stem. It produces cork or phellem towards the outer side and secondary cortex or phelloderm towards the inner side.

B.Vascular cambium – a ring of meristematic tissue formed by the joining of intra and interfascicular cambia. It produces secondary phloem towards the outer side and secondary xylem towards the inner side.

C.Phloem – food conducting complex tissue.

D.Xylem – water conducting complex tissue.

A.Radial, exarch vascular bundles – dicot root

B.Conjoint vascular bundles – stems

C.Radial, endarch vascular bundles – Not present in any part of the stem.

D.Conjoint, exarch vascular bundles – Not present in any part of the stem.

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.

The inner most part of the cortex in root and dicot stem is endodermis. it is single layered. Cells are barrel shaped and thick walled. On the radial walls and tangential walls, ligno suberised thickenings are present. These are called Casparian thickenings. Some of the endodermal cells lack casparian bands. These are called passage cells. These cells are present opposite to the protoxylem cells. Endodermis acts as check point, and prevents the outflow of water and minerals from the stele into cortex, and also acts as a barrier in the inflow of water and mineral from cortex and stele.

So, the correct option is ‘dicot stems and all types of roots’.

In the stems of dicotyledonous trees growing temperate regions, during secondary growth, vascular cambial ring produces secondary phloem towards the outer side and secondary xylem towards inner side.  When secondary growth is going on, old secondary xylems pushed towards the centre, and young secondary xylems are present nearer to the vascular cambial ring or just inner to the vascular cambial ring.

A.Secondary xylem and secondary phloem – produced by vascular cambium.

B.Cork and secondary cortex – produced by cork cambium.

C. Secondary cortex and phloem – secondary cortex is produced by cork cambium and phloem is produced from procambium.

D. Cork – it is produced by cork cambium

Pericycle is the outer most part of the stele. In dicot root, pericycle is continuous, parenchymatous and single layered.

A.Monocot stem – collateral, conjoint, closed and endarch vascular bundles are present.

B.Monocot root – radial vascular bundles are present.

C.Dicot root – radial vascular bundles are present.

D.Dicot stem – collateral, conjoint, open and endarch vascular bundles are present.

A.Fascicular/intra fascicular cambium – a strip of cambium present between the xylem and phloem.

B.Interfascicular cambium – a strip of cambium present between vascular bundles in dicot stem is called interfascicular cambium.

C.Phellogen – a ring of cambium formed in the cortex of dicot stem due to dedifferentiation of parenchyma is called phellogen or cork cambium.

D.Procambium – primary meristems that forms primary vascular tissues is called procambium.