Laser-induced chlorophyll fluorescence spectra of mung plants growing under nickel stress

The in vivo laser-induced chlorophyll fluorescence (LICF) spectra of mung (Vigna radiata Linn.) for the control, and nickel (a heavy metal)-treated plants were recorded in the region 600-800 nm with two characteristic bands lying at 686 nm and 730 nm using 488 nm argon ion laser line for excitation. The chlorophyll fluorescence intensity ratio (FIR) F680/F730, and peak, positions were calculated by evaluating curve-fitted parameters using Gaussian spectral function. It was found that the FIR decreases with increasing chlorophyll content in case of 0.1 mM nickel-treated plants. When the nickel concentration was raised to 1.0 mM, the FIR showed increasing trends, although it was much less than the control, with decreasing chlorophyll content. Our study demonstrates the use of LICF spectra in the early detection of heavy metal stress impact on crops, particularly mung.