Effects of NO2and O3Alone or in Combination on Kidney Bean Plants (Phaseolus vulgarisL.): Products of13CO2Assimilation Detected by13C Nuclear Magnetic Resonance

Publisher Website
Google Scholar
Abstract
The effect of exposure of kidney bean primary leaves to NO2 and O3, alone or in combination, on the fate of 13CO2 assimilated by photosynthesis was examined by 13C-NMR. There were more than 70 peaks appearing in the 13C-NMR spectra for substances extracted from leaves with 80% ethanol. The 16 relatively well resolved peaks corresponded to signals from three sugars, two organic acids and four amino acids. These signals were used to estimate pool sizes and l3C incorporation. Exposures to NO2 and O3 increased the amounts of sucrose and fructose, but not the incorporation of the 13C label during 10 min photosynthesis from 13CO2. This suggests the presence of photo-synthetically inactive pools of sucrose and fructose. Amounts of glycine and serine, and 13C incorporation into them, were increased by the exposure to the pollutants. The incorporation of 13C into alanine was stimulated by exposure to NO2, but not by exposure to O3 alone. The present study shows that with only simple procedures of sample preparations 13C-NMR provides information on the products of photosynthesis in leaves stressed by the two air pollutants.