Synchronous Luminescence Spectroscopy: A Powerful Tool for Investigation of Plant Physiology

Abstract

The study of the effect of various stresses like light stress, temperature stress, pollutant stress etc. may be performed using various spectroscopic techniques like absorption spectroscopy, fluorescence spectroscopy, fluorescence kinetics, Fourier Transform Infrared spectroscopy etc. In addition to these techniques the synchronous luminescence technique may be successfully employed to study the effect of stresses on the plant health. In the present attempt we are going to use the synchronous luminescence spectroscopy for the study of plant health and classification. As per our information the type of measurements made by us is the first report of this kind. It is seen that more information can be obtained from the analysis of synchronous luminescence spectra of the plant leaves.

Introduction

The text describes the use of synchronous luminescence spectroscopy as a technique to study plant health and the effects of different stresses on plants. This method records fluorescence by simultaneously scanning excitation and emission wavelengths while maintaining a fixed wavelength difference, allowing detailed analysis of plant pigments and physiological conditions.

Sample Preparation

Healthy leaves from plants grown under natural light, temperature, watering, and environmental conditions were selected from the nursery at Amravati. Typical leaves were used for recording synchronous luminescence spectra.

Experimental Method

The experiment used a SPEX Fluorolog-II spectrofluorometer to measure leaf fluorescence. Key experimental conditions included:

• Simultaneous scanning of excitation and emission monochromators
• Scan speed: 5 nm/s
• Fixed wavelength interval: 20 nm
• Monochromator bandwidth: 2 nm
• Excitation source: 45 W xenon lamp
• Fluorescence collected using an optical fiber arrangement

The emitted fluorescence from the leaf sample was analyzed to obtain synchronous luminescence spectra.

Results and Discussion

Synchronous luminescence spectra were recorded for different plant species. The spectra showed differences in:

• Number of peaks
• Peak intensity
• Peak position
• Peak width
• Additional small peak structures (peaklets)

Most plant leaves exhibited 2–5 narrow spectral bands with major peaks near:

• 366 nm
• 416 nm
• 500 nm
• 677 nm
• 772 nm

A dominant fluorescence peak was observed around 680 nm, associated with plant pigments such as chlorophyll. The main peak position varied between 650–683 nm, with a full width at half maximum (FWHM) of approximately 40–70 nm.

Significance of Findings

The spectral differences among plant species provide information about:

• Pigment composition
• Fluorophore concentration
• Plant physiological condition
• Stress-related changes

The structure and intensity of the peaks, especially the peaklets near the main chlorophyll fluorescence band, contain valuable information about plant health.

Conclusion

It is noticed that each sample of plant leaves from various families and plant types gives the different feature. An attempt can be made to record the synchronous luminescence spectra of all possible samples having some medicinal value or special characteristics such as oil producing plant, poisoning plant etc. and then by differentiating and classifying according to various parameters such as peaklets position, total number of peaks, position and intensity of various peaks in the spectra, full width at half maximum of each peak, the ratio of different peak heights. Some conclusion may be drawn about the position of the plant. An unknown sample may be identified as a medicinal and non medicinal plant. The synchronous luminescence spectroscopy is very much useful in the identification of various plants, which belong to different families, species etc. It is obvious that from the study of synchronous luminescence spectra large amount of information may be provided to the branch of bio-informatics. Synchronous luminescence spectral study also gives good information about leaf structure, degree of stresses and leaf contents. Thus the synchronous luminescence spectroscopy is very powerful tool for investigation of plant physiology.

References

[1] Gupta P.K. and Bhawalkar D. D. Current Sci., vol.,77, No 7, 1999. [2] Wolbarsht M. L., “Laser application in medicine and biology.” Pelenum press NewYork, Vol.1-5, 1991. [3] Gupta P. K., Pradhan A. S., Bhatnagar P. K. Reddy A. R. ‘Medical Physics for Human Health Care’.Scientific Publisher, Jodhapur. [4] Servik-Muraca E, and Benaron D. “ Trends in optics and photonics on Biomedical optical spectroscopy and Diagnostics,” Optical society of America, Washington DC, Vol. 3, 1996. [5] Majumdar S. K., Mohanty S. K., Ghosh N., Gupta P. K. and et al “A Pilot Study on the use of Autofluorescence Spectroscopy for Diagnosis of the cancer Of Human Oral Cavity,” Current Science, Vol. 79, No. 8, pp 1089-1094, 2000. [6] Lang Michael, Lichtenthaler H. K., “Changes in the Blue –Green and Red Fluorescence Emission Spectra of Beech Leaves During the Autumnal Chlorophyll Breakdown,” J. Plant Physiol, Vol. 138, pp. 550-553, 1991. [7] Krause G. H. and Wies E. ‘Chlorophyll Fluorescence and Photosynthesis: The Basics’, Annual Review Plant Physiology, Vol. 42, pp. 313-349, 1991. [8] Gitelson A. A. and Marzlyak M. N., “Signature Analysis of Leaf Reflectance Spectra: Algorithm Development for remote sensing of chlorophyll”, J. Plant Physiol, 148, 494-500, 1996. [9] Gitelson A. A., Buschmann C., Lichtenthaler H. K., “Leaf chlorophyll Fluorescence Corrected for Re-absorption by Means of Absorption and reflectance Measurements”, J. Plant physiology, Vol, 152, pp. 283-296,1998. [10] Lichtenthaler H. K., “ Vegetation stress an Introduction to the stress concept in plants”, J. Plant Physiol., 148, pp. 4-14, 1996.

Copyright

Copyright © 2026 A. D. Suryawanshi, D. D. Suryawanshi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.