Effect of Local Heating on Dormant Cambial Cells in the Branches of Lannea coromandelica (Houtt.) Merr

The effect of localized heating on cambial reactivation was investigated in dormant branches of Lannea coromandelica, a deciduous hardwood tree species by histological methods. The heating of young branches during winter for a duration of 10 and 20 days induced mitotic division in the fusiform cambial cells. The area of the branch exposed to heating exhibited wide cambial zone with a few differentiating xylem elements compared to that of non-heating branch. The heat treatment also caused an increase in length of fusiform cambial cells and height of rays. Histochemical studies revealed absence of starch in the xylem elements of heated branches. On the phloem side heating caused the removal of dormancy callose from sieve plates of dormant sieve tube members. The results suggest that localized heating of branches might provide an useful experimental model to understandthe dynamics of cambial reactivation in tropical deciduous tree species.