Abstract:

A shoot homoplastic graft in Carya cathayensis was performed and the healing responses were observed with light microscope and transmission electron microscope. The results showed: an isolating layer was firstly formed in the cambium zone in the first three days after grafting, then thickened in the next three days and disaggregated after the contents were absorbed by the callus cells, and at last disappeared on the 12th day. A series of healing responses in callus cells were induced during this process. After grafting, the plasmodesmata of the cells near the grafting face were closed while the others away from the surface were still active in transportation. Cell walls of some cells close to the isolating layer were degraded and the protoplasm was fused. The quantity of organelles such as mitochondria, endoplasmic reticulums and plastids was increased. Many multivesicular bodies and paramural bodies were observed. Starch granules were accumulated at the beginning and disappeared afterward.

Key words: Carya cathayensis, grafting, healing responses, isolating layer, ultrastructure