Grafting to improve nitrogen-use efficiency traits in tobacco plants

Nitrate plays a major role in the yield and quality of tobacco plants. This work explored the nitrogen-use efficiency (NUE) and how it can be affected by grafting. Two experiments were designed: in the first, using six commercial tobacco cultivars, the best cultivar for the NUE was selected and analysed for foliar NO3- content, total N, nicotine and nitrate reductase (NR) activity. The results showed the cultivar H-20 to have the best performance on NUE. It was further featured by the highest NR activity and total N and by the lowest NO3- and nicotine content, resulting in the highest foliar leaf biomass production and quality. In the second experiment it was tested whether the cultivar H-20 could be used as rootstock to improve the NUE of the other cultivars under study. The results showed that the grafted plants had improved the NO3- assimilation with respect to non-grafted plants. Hence grafting tobacco plants can be used as a quick and effective method to improve NUE, which has beneficial implications for human health and for a reduction in environmental pollution. (c) 2006 Society of Chemical Industry.