Besides phellem and phellogen,the root periderm comprises of:

Which of the following is not formed from the procambium?

Identify $X$ and $Y$ in the given figure.

$I.$ It is resistant to microorganisms
$II.$ It comprises dead elements
$III.$ It comprises highly lignified cell wall
$IV.$ It is the peripheral part
$V.$ It is dark and tough
Which of the above property does not belong to heartwood?

After the secondary growth,the youngest layer of secondary phloem in a dicot stem is located:

In an annual ring,the light coloured part is known as