Anatomically fairly old dicotyledonous root is distinguished from the dicotyledonous stem by

Anatomically fairly old dicotyledonous root is distinguished from the dicotyledonous stem by
  1. absence of secondary xylem
  2. absence of secondary phloem
  3. presence of cortex
  4. position of protoxylem

Solution

In dicotyledonous root, the condition of xylem is exarch as the protoxylem away from the centre and metaxylem towards the centre. In dicotyledonous stem (eg, Cucurbita), the condition of xylen is endarch as the metaxylem away from the centre and protoxylem towards the centre.

Asked in: NEET 2009 (Screening)

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