INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
A model considering light reabsorption processes to correct in vivo chlorophyll fluorescence spectra in apples
MARÍA E. RAMOS AND M. GABRIELA LAGORIO
Photochemical and Photobiological Sciences
Lugar: Cambridge; Año: 2006 vol. 5 p. 508 - 508
Chlorophyll-a contained in the peel of Granny Smith apples emits .uorescence upon excitation with blue light. The observed emission, collected by an external detector and corrected by its spectral response, is still distorted by light reabsorption processes taking place in the fruit skin and differs appreciably from the true spectral distribution of .uorescence emerging from chlorophyll molecules in the biological tissue. Reabsorption processes particularly affect the ratio of .uorescence intensities at 680 nm and at 730 nm. A model to obtain the correct spectral distribution of the emission, from the experimental .uorescence recorded at a .uorometer detector and corrected for the detector spectral sensitivity, is developed in the present work. Measurements of the whole fruit re.ectance, the peel transmittance and the .esh re.ectance allow the calculation of the reabsorption-corrected spectra. The model is validated by comparing the corrected emission spectra with that obtained for a thin layer of apple-peel-chloroplasts, where no reabsorption takes place. It is recommended to correct distortions in emission spectra of intact fruits due to light reabsorption effects whenever a correlation between the physiological state of the fruit and its .uorescence spectra is investigated.