Indirect measurement of photosynthetic pigments in the leaves of Jatropha curcas

Abstract

The aim of this work was to generate mathematical models capable of identifying photosynthetic pigments and soluble proteins from the leaves of Jatropha curcas using the relationship between classical readings performed by spectrophotometry and the chlorophyll meter, ClorofiLOG ® 1030. The work was conducted at Embrapa Cotton, in the city of Campina Grande, state of Paraíba, Brazil. For indirect analysis, portable equipment was used to read leaf discs at different stages of development. The chlorophyll in these discs was then determined using a classical method, while the Bradford method was used to determine soluble proteins. The data were subjected to analysis of variance and regression analyses, in which the readings obtained using the portable chlorophyll meter were the dependent variables and the photosynthetic pigments and soluble protein determined by the classical method the independents variables. The results indicated that with the exception of chlorophyll b and soluble protein, the mathematical models obtained with the portable chlorophyll ClorofiLOG ® 1030 can be used to estimate the concentration of photosynthetic pigments with high precision, thus saving time and the chemical reagents required for conventional procedures. Key words: Chlorophyll meter, calibration, chlorophyll, soluble protein ResumoO objetivo do presente trabalho foi gerar modelos matemáticos capazes de reportar os pigmentos fotossintéticos e proteína solúvel nas folhas de Jatropha curcas por meio da relação entre leituras realizadas por espectrofotometria clássica e por clorofilômetro, ClorofiLOG® 1030. O trabalho foi realizado na Embrapa Algodão, na cidade de Campina Grande (PB). Para a análise indireta, foi usado o equipamento portátil para leituras em discos foliares com diferentes estádios de desenvolvimento. A clorofila nestes discos foi então determinada usando o método clássico, enquanto que para a determinação da proteína solúvel utilizou-se a metodologia de Bradford. Os dados foram submetidos a análise de variância e de regressão em que as leituras obtidas com o medidor portátil de clorofila foram as variáveis dependentes e os pigmentos fotossintéticos e de proteínas solúveis, determinadas pelo método clássico foram as variáveis independentes. Os resultados indicaram que, com exceção da clorofila b, e proteína solúvel, os modelos matemáticos obtidos por meio do clorofilômetro portátil ClorofiLOG ® 1030 podem ser utilizados para estimar a concentração dos pigmentos fotossintéticos com alta precisão, poupando tempo e reagentes químicos normalmente utilizados em procedimentos convencionais.

Determination of photosynthetic pigments in fleabane biotypes susceptible and resistant to the Herbicide Glyphosate

“…Brito et al (2011) and Rigon et al (2012Rigon et al ( , 2013) also observed a high correlation coefficient among the methods of determination of pigments in cotton, sesame and jatropha, respectively.…”

“…Hendry and Price (1993) emphasize that the relationship Determination of photosynthetic pigments in fleabane biotypes ... coffee, with coefficients of determination of 0.92. As for Rigon et al (2013), when using the portable ClorofiLOG determiner for the crop of jatropha, obtained a coefficient of determination of 0.73. A high initial development and the total accumulation of photoassimilates for the resistant biotype may involve high interspecific competitive ability for this species.…”

“…Unlike, the portable readers of chlorophyll use non-destructive, simple and instant principles, allowing leaf ontogenetic studies of the crops (Salla et al, 2007). Portable chlorophyll meters are being used successfully in the determination of photosynthetic pigments in different species, as reported by Torres Netto;Campostrini, (2005) in coffee (Coffea arabica); Ciganda et al (2009) in corn (Zea mays); Busato et al (2010) in potato (Solanum tuberosum); Rigon et al (2012Rigon et al ( , 2013 in sesame (Sesamum indicum) and Jatropha (Jatropha curcas); and by Brito et al (2011) …”

Leaf gas exchange and biomass partitioning in Jatropha curcas L. young plants subjected to flooding and drought stresses

“…From the SPAD index values, we have calculated the concentrations of chlorophyll a and b and carotenoids, according to Rigon et al (2013) for J. curcas.…”

Calibration of a multi-species model for chlorophyll estimation in seedlings of Neotropical tree species using hand-held leaf absorbance meters and spectral reflectance

“…Although SPAD-502 measures absorption from leaves at two wavelengths, 660 nm (red) and 940 nm (near-infrared), ClorofiLog measures the absorption at three wavelengths, 635 nm and 660 nm (red) and 880 nm (near infrared - Barbosa et al 2013, Rigoni et al 2013). We expected ClorofiLog, which measures a third wavelength near the second absorption peak of Chl b (642 nm), to provide 832 iForest 9: 829-834 …”