It's callus tissue forming, but callus formation is neither a precursor nor prerequisite to root formation in Ficus c. Though roots frequently emerge through callus tissue, the formation of roots and callus are quite independent of each other in easy-to-root species like carica. That they often occur simultaneously is attributable to the fact that their cell divisions depend on similar internal plant and cultural/environmental conditions.

Roots are actually more apt to emerge from secondary phloem parenchyma cells than callus. They can also emerge from sites like vascular rays, cambial tissues, and lenticels.

You cannot "force" rooting. You can only provide preferred cultural conditions to the best of your ability and wait. Hopefully the roots will form along with a plumbing connection to leaf buds before rot organisms destroy the hydraulic system. ;o)

Al

With my limitied exeperience, the oberserved formation of callus is consistent with a cutting that will strike roots (not necessarily through the callus.) I have assoicated a cutting that forms a callus with a healthy cutting. I tend to worry about cuttings that don't ... they tend to suffer from rot or other issues.

-Steve

I tend to agree with both Stevec and Tapla, that (1-Stevec)
callus is a VERY good healthy sign (specially against
rotting), and (2-Al), roots do tend to come 'randomly'
from many places (from a healthy twig)...
George (NJ).

Oh yes - it's a very good sign. Callus is living tissue's response to wounding. Any time you take a cutting, the basal end will seal over with a plate of dead cells while the wound seals itself with a corky substance (suberin), which protects the cutting from dessication and disease pathogens. Behind this plate, living cells are beginning to divide into parenchyma cells that form the callus. As this occurs, cells in the (vascular) cambium are dedifferentiation and becoming stem (meristematic) cells. These cells are capable of redifferentiating into any of the plant organs (just like human stem cells) and differentiate into root initials if cultural conditions are favorable for root formation. The cells further organize into root primordia that emerge through stem or callus tissue at the same time vascular conducting tissues (the plumbing) are forming between root primordia and vascular tissues.

Since callus formation simply indicates the presence of viable tissues in the wound area, we can certainly consider it a good sign. I think though, that the two most influential factors in coaxing cuttings to strike are our ability to provide optimal cultural conditions for rooting and the vitality (stored energy level) of the cuttings.

Al

Thank you all.
That is encouraging to know that cutting is alive and doing something (OK if a bit lazy for rooting for a while). A potential rooter is much better than a dead cutting.