Graft union formation in tomato plants: peroxidase and catalase involvement.
OBJECTIVE
The use of grafted plants in vegetable crop production is now being expanded greatly. However, few data are available on the formation of graft unions in vegetables. In this work, the structural development of the graft union formation in tomato plants is studied, together with the possible relationship with activities of peroxidases and catalases.


METHODS
Tomato (Lycopersicon esculentum Mill.) seedlings of cultivar Fanny were grafted on the rootstock of cultivar AR-9704 using the 'tongue approach grafting' method, and were grown in a crop chamber. A study of the structural development of the graft union and the involvement of peroxidases and catalases in the process of graft formation was carried out during the first stages of the graft union (4, 8 and 15 d after grafting).


RESULTS
Observation of the structure of the graft union showed formation of xylem and phloem vessels through the graft union 8 d after grafting. In addition, root hydraulic conductance, L0, indicate that the graft union is fully functional 8 d after grafting, which coincided with an increase of peroxidase and catalase activities.


CONCLUSIONS
These results suggest that increased peroxidase and catalase activities might be implicated in graft development in tomato plants.
Fernandez-Garcia
Nieves
N
Departamento de Fisiología y Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, CSIC, Aptdo. Correos 164, 30100 Murcia, Spain.
Carvajal
Micaela
M
Olmos
Enrique
E
D001696:Biomechanical Phenomena; D002374:Catalase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008031:Lignin / Q000378:metabolism; D018551:Solanum lycopersicum / Q000201:enzymology* / Q000254:growth & development / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D009195:Peroxidase / Q000378:metabolism*; D018517:Plant Roots / Q000201:enzymology / Q000254:growth & development; D018520:Plant Shoots / Q000201:enzymology / Q000254:growth & development; D013997:Time Factors
D008031:Lignin; D006861:Hydrogen Peroxide; D002374:Catalase; D009195:Peroxidase