Effect of eggplant, field tomato, datura, orange nightshade and Iranian tobacco rootstocks on iron and chlorophyll concentrations in grafted tomato

Among the most important quality parameters of irrigation water used for greenhouse crops, alkalinity of water is considered critical due to its impact on pH of soil or growing medium solution. In this study, shoot and root Fe contents and SPAD index were investigated in non-grafted and grafted tomato (greenhouse tomato) plants onto five rootstocks (eggplant, datura, orange nightshade, local Iranian tobacco, and field tomato), exposed to 0, 5 and 10 mM NaHCO3 concentration, to determine whether grafting could improve alkalinity tolerance of tomato. Results showed that significant reduction of shoot and root Fe content under high NaHCO3 level was observed in both grafted and ungrafted plants. The highest reduction in the shoot Fe content was observed in control plants (greenhouse tomato) under 10 mM sodium bicarbonate. Values of SPAD index was decreased significantly at 5 and 10 mM NaHCO3 irrespective of rootstock type. Adjusted pH of the solution surrounding the roots in datura rootstock may have possibly a role in the reduction of bicarbonate-induced deleterious effects. Thus, it is concluded that using datura rootstock could improve alkalinity tolerance of tomato plants under NaHCO3 stress.