FIGURE 6.

MS images of selected amino acids in B73 and Mo17 maize root sections grown in 10 mM ammonium ion, either ¹⁴NH₄Cl or ¹⁵NH₄Cl, compared to the control grown in water. The first three sets of images are of the monoisotopes (M peak) containing only ¹²C and ¹⁴N. The last set is of the isotope (M + 1 peak) from ¹⁵NH₄Cl data containing one isotope of either ¹⁵N or ¹³C. The root sections were made at 2 cm below the seed when the root reached the length of 10–11 cm. The numbers below each amino acid label correspond to the maximum intensity scale used to produce false color image. The scale bar is 500 μm.