CORESTA Congress, New Orleans, 2002, APPOST 11

Dry matter production and lead distribution in different tobacco varieties grown in greenhouse in presence of lead

Istituto Sperimentale per il Tabacco, Scafati, Italy
A greenhouse trial was carried out, during year 2000 and replicated in 2001, to evaluate lead distribution and accumulation in tobacco plants experimentally exposed to the heavy metal and to reveal possible differences depending on variety and or type, with the overall aim to obtain knowledge useful to develop agricultural practices which minimize lead content in tobacco. The plants were grown in pots, one plant per pot, subjected to a total of 30 treatments: 6 varieties belonging to 3 tobacco types, 5 salt rates (control; Pb1 = 4g of Pb/kg of peat; Pb2 = 8g of Pb/kg of peat; N1= 3.88g of KNO3/kg of peat (nitrate rate as in Pb1); N2 = 7.76 g of KNO3/kg of peat (nitrate rate as in Pb2) and 10 plants per treatment. The following parameters were collected: height, leaf (5 leaf primings), stalk, and root dry matter production. In both years, the analysis of variance showed a significant effect of salt rate and variety on each parameter (P=0.01). During the vegetative cycle, the plants exposed to lead rates Pb1 and Pb2 exhibited a gradual recovery in growth respect to those of the other treatments. This recovery was more rapid and, almost always, total at Pb1 than Pb2 rate. The results obtained suggested that at lower rate the effect of lead was masked by the concomitant presence of nitrate, while at higher rate the effect of lead became preponderant. The extent of lead effect depended on the parameter considered: the root tissue dry matter was the most affected parameter, while the dry matter production of leaves was the less one. Furthermore, in consequence of the different plant part analysed, the tobacco varieties assayed showed either a ranking order with some correlation to type or a random distribution. Data of lead content in the different part of plant will be presented and discussed."This research was carried out with financial support of the Commission of the European Community, Tobacco and Information and Reserch Fund, project 96/T/35 "Monitoring and minimizing heavy metal contents in tobacco". It does not necessarily reflect the views of the Commission and in no way anticipates its future in this area.