IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Concentration imaging of chlorophyll, carotenoids and anthocyanins in leaves
Autor/es:
GABRIELA B. CORDON; MARÍA GABRIELA LAGORIO
Lugar:
Mendoza
Reunión:
Congreso; 21st I-APS Conference; 2011
Institución organizadora:
Inter-American Photochemical Society
Resumen:
A computational
vision-methodology to determine the pigments concentration in plant leaves with
spatial resolution from a digital image has been developed. For this purpose,
reflectance spectra of uniformly colored leaves were recorded as a first step. Reflectance
spectra were obtained from 300 to 700 nm, using a spectrophotometer equipped
with an integrating sphere. Barium sulphate was used as 100% reflectance (white
reference). Seven reflectance spectra were averaged for each species and the
resultant spectrum was used for further derivation of colour coordinates (R,
G and B). The selected species were: Hedera
helix, Liquidambar styraciflua, Populus alba, Rosa
sp., Gardenia jasminoides, Schefflera arboricola, Aloysia triphylla and Ficus benjamina. On these leaves,
chlorophyll-a, chlorophyll-b, carotenoids and anthocyanins were quantified as
usual by solvent extraction and subsequent spectrophotometric measurement.
Values for the RGB coordinates were calculated from reflectance spectra, and
they were correlated with the pigment concentrations.
Values for the R component decreased non-linearly as chlorophyll
concentration declined. Values for G component decreased linearly with
chlorophyll content. Values for the B component, on the other hand resulted
insensitive to chlorophyll concentration. An excellent correlation was finally
found for the sum of R and G with the chlorophyll content. Other good correlations were found between the ratio R/G and the proportion
anthocyanins/total chlorophyll and the ratio B/G and the carotenoids content.
On the other hand, images from
another set of colored leaves were captured using a commercial scanner (HP-DeskJet F380 de
Hewlett-Packard) and they were digitally processed to obtain R, G and B
bands. The scanned images
in TIFF format (Tagged Image File Format) with a resolution of 300 ppp and a depth
of 24 bits were digitally processed using the ERDAS IMAGINE 8.4 program. Using
this software the TIFF images were imported to IMG format and they were
subsequently separated in R, G and B bands.
Using the
correlations between the color coordinates (R, G and B) and pigments
concentration, inferred from the homogeneous leaves, the concentration of
pigments per pixel in the other set of leaves were estimated.
The proposed
methodology allows quantifying chlorophyll-a, chlorophyll-b, carotenoids and
anthocyanins in a rapid and non invasive way, thus avoiding destructive solvent
extractions, which requires too much work and time in lab. Additionally, image
analysis shows a great potential due to the low cost of implementation, as it
merely requires a commercial scanner and an image processing program.