Water and nutrient uptake of grafted tomato plants grown under saline conditions

Tomato seedlings, cvs. Fanny and Goldmar, were grafted on the rootstock cv. AR-9704 using the tongue approach grafting method and were grown in a crop chamber. The response of the grafted varieties to salt exposure (75 mmol L-1 NaCl) was compared with ungrafted plants. Under non saline conditions, root hydraulic conductance (L-0) of both cultivars decreased when they were grafted. When salinity was increased, no significant alteration of L-0 between grafted and ungrafted plants was observed. The L-0 measurements made below and above the graft union, indicated that the graft union was not a barrier to water passage. Salinity treatment significantly increased the percentage of water movement via the apoplastic pathway for grafted and ungrafted plants. Chloride and sodium concentrations in the xylem and leaves of NaCl treated plants were higher in ungrafted than in grafted plants. The small effect of NaCl treatment on grafted plants could indicate that grafting provides a useful tool for increasing the salt stress resistance of plants.