Assimilation of Nitrogen Dioxide in Selected Plant Taxa

Abstract

Abstract The production of a novel “ nitrogen‐dioxide‐philic plant ” that can grow with NO 2 as the sole nitrogen source was investigated as a possible solution to pollution. 217 plant taxa were screened for the assimilation of NO 2 , among them 50 wild herbaceous plants collected from roadsides, 60 cultivated herbaceous plants and 107 cultivated woody plants. It was discovered that the NO 2 ‐derived reduced nitrogen [μg N/mg dry weight] differed by a factor of 657 between the highest ( Eucalyptus viminalis , 6.57) and lowest ( Tillandsia ionantha and T. caputmedusae, 0.01) level in the 217 taxa. The capability of plants to assimilate NO 2 was also found to change in a family‐dependent manner. Compositae, Myrtaceae, Salicaceae and Solanaceae had taxa with high NO 2 assimilation capability, while none of the Gramineae, Theaceae and Rosaceae plants examined showed high NO 2 assimilation capability. The 217 taxa included two species of the Solanaceae family (tobacco and petunia), both of which showed a high NO 2 assimilation and their reduced nitrogen derived from NO 2 was the third and twenty‐sixth highest. This suggested that the Solanaceae family includes plants of high NO 2 assimilation. Therefore, in this study eight taxa of the Solanaceae family and four taxa of other families were investigated for NO 2 assimilation in the same manner as reported previously by the fumigation of plants with 15 N‐labelled NO 2 followed by the mass spectroscopic analysis based upon the reduced nitrogen derived from NO 2 . The eight taxa Solanaceae included tobacco ( Nicotiana tabacum ) and petunia ( Petunia X hybrida ), ground cherry ( Physalis alkekengi var. franchetii ), tomato ( Lycopersicon esculentum ), datura ( Datura innoxia ), potato vine ( Solanum jasminoides ), red pepper ( Capsicum annuum ) and green pepper ( Capsicum annuum var. grossum SENDTN.). The four taxa included two ivy cultivars ( Hedera helix “Pittsburgh” and Hedera helix “Wonder”), an evergreen creeper ( Ficus thunbergii ) and kenaf ( Hibiscus cannabinus ). Among the twelve taxa, kenaf, tobacco and ground cherry showed the highest, second and third highest values, respectively, of reduced nitrogen derived from NO 2 in plants, which reflects the capability to assimilate NO 2 ‐nitrogen. The quantitative significance of these findings is discussed in relation to the reduction of nitrogenous pollution by the atmospheric NO 2 pollution.