SECONDARY GROWTH IN ROOTS-2   

We have studied secondary growth in stems first because of the great importance of woody stems and because of their familiarity. You will discover that identical processes occur in roots. There is one important thing to keep in mind as you consider roots. Remember that the procambium forms a solid core of vascular tissue in roots. Thus a pith is generally NOT PRESENT and xylem occupies the center of the root. There are exceptions, of course, but we will concentrate on the most central examples before we venture into the variations.

The Stele of a Typical Dicot Root at the end of
Primary Growth

3-D Representation of a root at the end of
Primary Growth

If Secondary Growth Occurs

The Vascular Cambium remains active between the Phloem & Xylem.

It becomes Continuous because cells of the Pericycle are recruited.

The Vascular Cambium operates the same way as it does in Stems.

The Secondary Xylem in the Roots of herbaceous plants usually contains a lot of Parenchyma while that in trees resembles wood.

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