Question

Derivative of the secondary meristem in the stellar region are
A. Phellem and Phelloderm
B. Alburnum and primary phloem
C. Duramen and alburnum
D. Primary xylem and secondary phloem

Answer 1

The type of meristematic tissue responsible for the secondary growth in plants, which is growth in girth or the thickness of plants is known as secondary meristem. Secondary meristem is opposed to primary meristem which is involved in the primary growth, that is the growth in height or length. Cells that differentiate into the secondary permanent tissues of the plant are formed from secondary meristem.

Complete answer:
Option A. Phellem and Phelloderm: Cells which grows inwards from phellogen are termed as phelloderm and cells that develop outwards from phellogen layer is termed phellem or cork. Phelloderm are composed of living parenchyma cells. Phellem is an air-filled protective tissue present on the outside. Phellem and Phelloderm are not the derivative of secondary meristem in the stellar region.
Hence option A is not correct.
Option B. Alburnum and primary phloem: The outer living layers of the secondary wood of trees is called Alburnum, which is also known as the sapwood. Alburnum helps in transporting minerals and water to the crown of trees. Alburnum or sapwood develops from secondary lateral meristem. But primary phloem develops from provascular tissue.
Hence option B is not correct.
Option C. Duramen and alburnum: Duramen, also known as Heartwood, is the central wood of trees. It is dark in color because the cells usually contain tannins or other substances and sometimes, they are aromatic. Outer living layers of the secondary wood of trees is known as the Alburnum, which is also called sapwood. Both the duramen and alburnum are derivatives of secondary meristem.
Hence option C is the correct answer.
Option D. Primary xylem and secondary phloem: The xylem that is formed during the primary growth from procambium of apical meristems is known as primary xylem. Type of phloem that forms from the vascular cambium during the secondary growth is known as secondary phloem. Since both these are not formed as a derivative of secondary meristem in stellar region.
So, option D is not correct.

So, Option C Duramen and alburnum is the correct answer.

Note:
The duramen or heartwood is mechanically strong, decay resistant, and are less easily penetrated by wood-preservative chemicals than other types of wood. One or more layers of functional and living cells of sapwood are converted periodically into heartwood. The cells of sapwood or alburnum contain more water and lack the deposits of darkly staining chemical substances that are commonly found in heartwood.