Some vascular bundles are described as open because these

Some vascular bundles are described as open because these
  1. are surrounded by pericycle but to endodermis
  2. are capable of producing secondary xylem and phloem
  3. possess conjunctive tissue between xylem and phloem
  4. are not surrounded by pericycle

Solution

In open vascular bundle, cambium is present between xylem and phloem of the same vascular bundle, $e g$, dicot stems. Due to the presence of cambium, secondary growth in stem occurs and secondary permanent tissues (secondary xylem, secondary phloem and vascular rays) are formed.

Asked in: NEET 2011 (Mains)

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