Question

Duramen is
(a) Sapwood
(b) Heartwood
(c) Bark
(d) Periderm

Answer 1

Hint: It is a dead, central wood of trees that usually contain tannins or other substances that make it dark in color and sometimes aromatic. It is of various colors depending upon the species of the tree.

Complete step by step answer:
Duramen is called the heartwood. After certain years of growth, the xylem elements of the stems of a number of trees develop dark brown coloration, especially in the central or innermost layers. This region comprises a dead element with highly lignified walls and is called heartwood or Duramen.

- Heartwood is mechanically the strong and resistant wood which does not decay easily, and very few wood preservatives penetrate inside it.
- More than one layer of living and functional sapwood cells are periodically converted to heartwood.
- Most of the plants continue to grow throughout their lifetimes, and they grow through the combinations of cell growth and cell divisions.
- The formation of secondary tissues from lateral meristems is called Secondary growth. It increases the diameter of the stem.
- Secondary tissues constitute the bulk of the plant in woody plants.
- They provide protection, support, and conduction of water and nutrients.
- Vascular cambium and cork cambium or phellogen are two types of lateral meristem that togetherly form Secondary tissues.
- Secondary vascular tissues are produced by Vascular cambium while phellogen forms periderm.
So, the correct answer is, ‘Heartwood’.

Note: The outer or peripheral light- colored functional secondary xylem or wood formed during secondary growth in dicotyledonous is called sapwood or laburnum. All tissue present outer to the vascular cambium is called bark. Cork, Cork cambium and secondary xylem is called periderm.