CASE STUDY OF SECONDARY GROWTH IN ROOT AND STEM
Secondary Growth in Ficus Root
Lenticel
Cork
Cork cambium
Secondary cortex
Secondary phloem
Secondary xylem
Cambium
Primary phloem
Primary xylem
Pith
Fibre
Fig.: T.S. of root of Ficus (diagrammatic)
Cork cambium
Secondary phloem
Secondary xylem
Conjunctive tissue
Medullary ray
Tannin
Cambium
Primary phloem
Pith
Metaxylem
Protoxylem
Fibre
Lenticel
Cork
Contains many layers of thick suberised cells
showing characteristic brick like arrangement
Secondary cortex
Comprises of few layers of parenchymatous cells.
Some cells of this region contain chloroplasts
while a few others show thick walled fibres.
Tannin filled cells are also abundant.
Conjunctive tissue
Fig.: Ficus : Detailed structure of a part of T.S. of root
Thin and thick walled prosenchyma that
generally constitutes conjunctive tissue.
Note: Presence of chloroplast in cortex indicates aerial
nature of root. Abundant secondary xylem and phloem
Primary xylem indicate mechanical function of root.
Secondary Growth in Vitis Stem
Vitis vinifera (grapevine) is a liana type of plant and is appropriate for the study of internal structure of a
typical dicot stem. The transverse section of its stem showing the various parts of both primary and secondary origin is
as follows.