BORON EFFECT ON MINERAL NUTRIENTS OF TOBACCO

Abstract

Information on the effect of boron (B) nutrition on nutrient uptake and concentration and biomass production in tobacco plants (Nicotiana tabacumL.) is limited. Thus the aim of this study was to analyze the response of the nutritional state and biomass in tobacco plants administered different B treatments (B1 : 5 μmol/LH₃BO₃, B2 :  10 μmol/LH₃BO₃, B3 :  20 μmol/LH₃BO₃). Tobacco plants were grown under controlled conditions and submitted to regular fertilization with macro- and micro-nutrients. The concentration of the elements organic nitrogen (N), phosphorus (P), potassium (K), sodium (Na), magnesium (Mg), calcium (Ca), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), chloride (Cl), and B were analyzed in roots and leaves. The increase in the B application in the culture medium translated as a progressive accumulation of this element. Similarly, the macronutrients N, P, K, and Na responded positively to the dosage of B, notably increasing in concentration. Nevertheless, Mg responded negatively, declining considerably in concentration in the roots and leaves. The relationship between the elements B and Ca in our experiment can be defined as synergetic, showing a steady accumulation and translocation of Ca as the B dosage increased. The root and foliar concentrations of the micronutrients Fe and Mn also increased with the B dosage, whereas Cu and Zn to a lesser degree diminished in concentration. Finally, the positive effect that increased B application exerted on dry-material production in the roots and leaves could be explained by the general improvement in the nutritional state, particularly of the essential macronutrients N and P.

Acknowledgments