Biology · Anatomy of Flowering Plants · NEET
It comes from two places that join together. First, the conjunctive parenchyma (the tissue between the xylem and phloem) that lies just below the phloem strips becomes meristematic. Then the pericycle cells lying above each protoxylem point also start dividing. These pieces link up into one continuous cambial ring. For NEET, remember the exact wording: 'below the phloem' and 'above the protoxylem'.
It is completely secondary in origin. Unlike the dicot stem (which already has a strip of fascicular cambium from the start), the dicot root has NO cambium in its primary structure. The whole cambium is formed fresh at the time of secondary growth. This is a favourite NEET trap, so lock it in.
The pericycle is the seat of initiation of both lateral roots AND the vascular cambium. During secondary growth, the pericycle cells above the protoxylem points turn meristematic and complete the cambial ring. NCERT states this directly, so NEET can ask 'pericycle gives rise to what?' — answer: lateral roots and vascular cambium.
Because it forms from two parts at different distances from the centre. The conjunctive parenchyma below the phloem lies deeper (closer to the centre), while the pericycle above the protoxylem lies more towards the outside. When these join, the ring is uneven, so it looks wavy. Later, more division makes it round.
In a dicot STEM the cambium is partly primary — the fascicular (intrafascicular) cambium is already present inside the open vascular bundles, and only the interfascicular cambium is added later. In a dicot ROOT there is NO cambium to start with, so it is 100% secondary, formed from conjunctive parenchyma plus pericycle.
Conjunctive tissue (conjunctive parenchyma) is the parenchyma that lies between the xylem and phloem patches in a radial dicot root. During secondary growth, the conjunctive parenchyma below the phloem is the first tissue to become meristematic and start the cambium. NEET 2026 matched 'conjunctive tissue' with 'tissue between xylem and phloem'.
In the dicot root the vascular cambium originates from:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Conjunctive parenchyma below the phloem bundles plus pericycle cells above the protoxylem points, joining into one wavy cambial ring — fully secondary.
No. Monocots normally do not show secondary growth, so no vascular cambium ring forms. This concept is specific to dicot roots (and dicot stems).
Once the ring is complete, it cuts off secondary xylem towards the inside and secondary phloem towards the outside, adding girth to the root.
No. NCERT says the pericycle is the seat of initiation of both lateral roots and the vascular cambium during secondary growth. Both are common NEET one-liners.
