Laser-induced fluorescence spectra were used to characterize the effect of cadmium on the pigment status of the leaves of <i>Cajanus cajan</i> L. Laser-induced fluorescence spectra of untreated as well as cadmium treated (0.01 mM, 0.10 mM, and 1.00 mM) <i>Cajanus cajan</i> L. were recorded using the 355 nm line of a Nd:YAG laser as the excitation source and a monochromator with an intensified charge-coupled device as a detector in the region 400–800 nm. The fluorescence intensity ratios (FIR) of control as well as treated <i>Cajanus cajan</i> L. have been calculated by evaluating curve fitted parameters using a Gaussian spectral function. In addition, some growth parameters, such as photosynthetic pigment content, were also measured. The 355 nm line of the laser-light-excited leaves not only showed a fluorescence emission in the red spectral region (650–800 nm), but also in the blue-green region (400–570 nm). The chlorophyll FIR F690/F740 strongly correlated with the photosynthetic pigment content (total chlorophyll and carotenoids) and its ratio. Consequently, a correlation was also seen between the ratio of the blue-green fluorescence F470/F540 and the photosynthetic pigment content. The results indicated that the plants treated with 0.01 mM of cadmium exhibited better growth, while higher concentrations of cadmium were hazardous for <i>Cajanus cajan</i> L.
Vol. 3, Iss. 5 Virtual Journal for Biomedical Optics
Renu Maurya and R. Gopal, "Laser-Induced Fluorescence Ratios of Cajanus cajan L. Under the Stress of Cadmium and Its Correlation with Pigment Content and Pigment Ratios," Appl. Spectrosc. 62, 433-438 (2008)