The effects of nutrient deficiencies on the laser-induced fluorescence spectra of intact corn plants were studied to determine the utility of the LIF technique as a field and remote sensing tool for detection of nutrient deficiencies. A pulsed nitrogen laser emitting at 337 nm was used as the excitation source. The fluorescence maxima in corn were at 440, 690, and 740 nm. A decrease in fluorescence at 690 and 740 nm was observed for those plants deprived of phosphorus, nitrogen, and iron. The absence of nitrogen and iron also caused a small decrease in fluorescence at 440 nm. Plants deprived of calcium, sulfur, and magnesium showed no significant change in fluorescence at any of the bands. The lack of potassium increased the fluorescence at 690 and 740 nm more than threefold along with a small decrease at 440 nm.
Emmett W. Chappelle, James E. McMurtrey III, Frank M. Wood, Jr., and W. Wayne Newcomb, "Laser-induced fluorescence of green plants. 2: LIF caused by nutrient deficiencies in corn," Appl. Opt. 23, 139-142 (1984)