Early Vegetative Growth of Tomato Plants in Media Containing Nitrogen Source as Nitrate, Ammonium, or Various Nitrate?Ammonium Mixtures with Bicarbonate Addition

Abstract

Abstract The effect of various concentrations applied in media with , , or various mixtures of both on the accumulation of biomass and early vegetative growth of tomato (Lycopersicon esculentum Mill.) plants was tested in experiments carried out in hydroponics. The optimum concentration was 5 mM and was similar in all the combinations of the N source applied at 3 mM concentration. The average biomass of -grown plants without reached only 50% of the value for the plants if was used as the N source. With respect to the growth without , the biomass increased by about 160% or 130% with or used as the N source, respectively. The biomass of -grown plants in media with reached only about 42% of the value obtained by plants cultivated in media with and . Similar relations were observed in the size of leaf blades. A simultaneous addition of to the medium containing ameliorated the toxic effects of this compound. The optimum ratio of for the growth of plants was ≤ 1. The use of such proportions of nitrogen (N) forms in the medium stimulated the accumulation of biomass to about 115% of the mass attained by -grown plants. The addition of to the medium containing the N source in the two forms at an optimum ratio stimulated an increase in the biomass of plants by about 180% with respect to plants without . Certain growth parameters calculated, i.e., shoot to root ratio, specific leaf area, and relative growth rate confirm the ameliorating effect of if added to media containing and the stimulating effect of on the biomass production of different organs of the plants.