Soil Nitrogen Fertilization Effects on Phytoextraction of Cadmium and Lead by Tobacco (Nicotiana tabacumL.)

Abstract

A greenhouse experiment using 24 plastic pots filled with 6 kg of Pb-and Cd-contaminated soil was carried out. In all 24 pots, soils were heavy metal-contaminated with 10 mg Cd kg −1 soil and 500 mg of Pb kg −1 soil by using CdCl and PbNO 3 . Two-month-old tobacco (Nicotiana tabacum L.) plants were used to extract these heavy metals. Results showed that tobacco is able to remove Cd and Pb from contaminated soils and concentrate them in its harvestable part, that is, it could be very useful in phytoextraction of these heavy metals. Increasing additions of ammonium nitrate to soil (50, 100, and 150 mg N kg −1 soil) significantly (p ≤ .05) increased aboveground Cd and Pb accumulation during a 50-day experimental period, whereas increasing additions of urea to soil (50 and 100 mg N kg −1 soil) did not show these effects at the same significance levels. Increasing additions of ammonium nitrate to soil shows as dry matter increases, both accumulated Cd and accumulated Pb also increase when tobacco plants are growing under Pb-and Cd-contaminated soil conditions. Higher Pb concentrations depress Cd/Pb ratios for concentrations and accumulations, suggesting that Pb negatively affects Cd concentration and/or accumulation.

USO POTENCIAL DEL HUIZACHE (Acacia farnesiana L. Will) EN LA FITORREMEDIACIÓN DE SUELOS CONTAMINADOS CON PLOMO

“…Furthermore, nitrogen could have contributed in the decrease of lead effects (Rodríguez-Ortíz et al, 2006); this is supported with the results of the present study, where an increasing tendency in photosynthetic rate was observed as lead and nitrogen concentrations in substratum increased (Figure 1). Heavy metals accumulation produced oxidative stress and the acclimatization to stress conditions by means of genes induction related with response to oxidative stress can affect the photosynthetic rate (Rossel et al, 2007).…”

“…Sin embargo, la interacción entre esos dos factores fue altamente significativa (P=0.0074) y la media general de tasa fotosintética fue de 17.06 µmol·m Una alta tasa fotosintética en la presencia de altas concentraciones de plomo en el sustrato puede ser indicativo de que el huizache pudo desarrollar mecanismos de defensa, entre los que se pueden encontrar la acumulación de plomo en la pared celular inmovilizando los iones y evitando sus efectos tóxicos o bien mecanismos de detoxificación como se han encontrado en Allium sativum (Jian y Liu, 2010). Además, el nitrógeno pudo haber contribuido a que los efectos del plomo fueran reducidos (Rodríguez-Ortíz et al, 2006), lo cual se confirma con los resultados de este estudio en donde se identificó una tendencia de incremento en la tasa fotosintética a medida que se incrementaron las concentraciones de plomo y de nitrógeno en el sustrato en el que creció el huizache (Figura 1). La acumulación de metales pesados provoca estrés oxidativo y la aclimatación a condiciones de estrés mediante la inducción de genes relacionados con respuesta al estrés oxidativo puede hacer que se altere la tasa fotosintética (Rossel et al, 2007).…”

Effects of municipal waste compost and nitrogen fertilizer on growth and mineral composition of tomato

“…They concluded that such positive effect of N was probably due to the enhancing effect of N on root volume and growth. Rodriguez-Ortiz et al (2006) showed that increase of ammonium nitrate application to soil (50,100, and 150 mg N kg -1 soil) significantly increased the aboveground accumulation of cadmium (Cd) and lead (Pb) in tobacco during a 50-day experimental period. Eriksson (1990) reported that Cd availability in two soils was increased after the application of acidifying N fertilizers.…”

Soil cadmium toxicity and nitrogen deposition differently affect growth and physiology in Toxicodendron vernicifluum seedlings

“…However, LEN cannot attenuate the Cd contents resulting from HCd. This discrepancy may be caused by an increase in the ionic strength of the soil solution and ensuing ion exchange reactions, or by soil acidification (Rodriguez-Ortiz et al 2006). On the other hand, Cd primarily entering the plant tissues from the soil via the root system may be the reason causing a higher proportion of Cd remaining in the roots (Seregin and Ivanov 2001).…”