LICF Spectrum as a Fast Detector of Chlorophyll Damage in Safflower Growing under Mutagenic Stress

The present investigation envisages the in vivo measured laser induced chlorophyll florescence spectra of EMS (Ethyl methane sulphonate) treated safflower leaves. Seeds of safflower were treated with 0.5% EMS for three treatment durations (3h, 5h and 7h) to raise the populations. The effect of EMS treatment on chlorophyll content in the leaves was assessed using laser induced chlorophyll fluorescence (LICF) spectra in the early stage of growth. The LICF spectra of leaves were recorded in the region of 650-780 nm using 405 nm violet laser as excitation source and PMT as detector. The chlorophyll fluorescence spectra with peaks at 685 and 735 nm were used for monitoring the growth of plants after the treatment and were analyzed using Gaussian spectral functions with curve fitted parameters to determine the peak positions, area under the spectral curve and the florescence intensity ratio (FIR) F685/F735. FIR is an indicator of chlorophyll content in mesophyll layer and has inverse relation with chlorophyll content in the plant leaves. As the duration of treatment increased FIR ratio increased with corresponding decrease in the chlorophyll content. Total carotenoids content has also been found to be decreased along with the increment of treatment duration. This change in intensity can be discussed in the light of variation in photosynthetic activity. Thus we demonstrate the use of LICF spectra for early, fast and nondestructive detection of chemical induced chlorophyll reduction in safflower.