Development of tensile strength in conventional and approach grafts in Sedum telephoides

Abstract

Conventional autografts between severed internodes of Sedum telephoides attained a tensile strength of approximately 75 g breaking weight (BW)/mm2 graft area (GA) by 20 days after grafting. Approach grafts between cut surfaces were characterized by a tensile strength of approximately 42 g BW/mm2 GA by 10 days after grafting. Approach grafts in which membrane filters were inserted between the grafting surfaces attained a tensile strength of approximately 10 g BW/mm2 GA by 5 days after grafting. These results indicate that the cell wall deposition responsible for the initial cohesion of the stock and scion contributes approximately 13% of the tensile strength of the graft union in compatible Sedum autografts. Similarly, the interdigitation of callus cells and vascular redifferentiation (and the relatively small amount of wall deposition associated with each) contribute approximately 44 and 43%, respectively, to the tensile strength of the Sedum graft union. The data suggest synergistic interaction between different mechanisms of graft formation.