Guerra R.,University of Algarve |
Garde I.V.,University of Algarve |
Antunes M.D.,University of Algarve |
da Silva J.M.,BioFIG |
And 2 more authors.
Scientia Horticulturae | Year: 2012
This study aimed to identify physiological markers in superficially scalded 'Rocha' pear (Pyrus communis L. 'Rocha') that would relate to chlorophyll a fluorescence (CF), allowing a non-invasive diagnosis of the disorder. Conditions chosen before shelf life provided two fruit groups with different developing patterns and severity of superficial scald: T fruit fully developed the disorder in storage, while C fruit developed it progressively throughout shelf life. Principal component analysis (PCA) of all the measured variables, and simple linear correlations among several major parameters and scald index (SI)/shelf life showed that scald and ripening/aging were concurring processes, and that it was not possible to isolate a particular variable that could deliver a direct non-invasive diagnosis of the disorder. For both fruit groups the SI resulted from the balance between the reducing power (OD200) and the content of conjugated trienols (CTos) and α-farnesene (α-Farn) in the fruit peel. At OD200>150 there was a linear relationship between CTos and OD200, suggesting that the level of antioxidants was self-adjusted in order to compensate the CTos level. However, at OD200<150 this relationship disappeared. A consistent linear relationship between CTos and α-Farn existed throughout shelf life in both fruit groups, contrarily to the early storage stage, when those compounds do not relate linearly. The CF variables F0, Fv/Fm, and the colorimetric variables, L* and h° were used in multi-linear regressions with other physiological variables. The regressions were made on one of the fruit groups and validated through the other. Reliable regressions to α-Farn and CTos were obtained (R≈0.6; rmsec≈rmsep). Our results suggest that a model based on CF and colorimetric parameters could be used to diagnose non-invasively both the contents and the relationship between α-Farn and CTos and hence the stage of scald development. © 2011 Elsevier B.V.
Bernal R.A.,BioFIG |
Coradin V.,Laboratorio Of Produtos Florestais |
Camargos J.,Laboratorio Of Produtos Florestais |
Costa C.,Brazilian National Council for Scientific and Technological Development |
IAWA Journal | Year: 2011
Woods from an important group of Lecythidaceae species called "tauari" can hardly be identified in the field by their gross and general features. In this study we show that, when properly delimited to the genera Allantoma, Cariniana and Couratari, wood anatomical characteristics can be used to identify the species known as "tauari", even though it is not possible to separate all species. In addition to anatomical characters, wood colour is an important character to help distinguish species of Cariniana and Allantoma from species of Couratari. Detailed wood anatomical descriptions from "tauari" woods Allantoma, Cariniana and Couratari are given and a table with diagnostic differences is presented. Common characters of this group are axial parenchyma in narrow continuous bands, prismatic crystals in chambered axial parenchyma cells and silica bodies in ray cells. Microscopic features that help in species identification are: fibre pitting (minutely or distinctly bordered), traumatic intercellular canals, average vessel diameter, vessel element length, axial parenchyma strand length, and ray height and width.
Garde I.,FARO |
Antunes M.D.,FARO |
Marques Da Silva J.,BioFIG |
Guerra R.,FARO |
Acta Horticulturae | Year: 2012
This study aimed to test whether the chlorophyll a (Chla) fluorescence determined by a low-cost non-modulated fluorometer could provide fast, reliable and non-invasive estimators of superficial scald in 'Rocha' pear (Pyrus communis L. 'Rocha'). Fruit were harvested before the optimal maturation stage and cold stored under normal atmosphere for 7 months (NA: 0°C, 90-95% RH) and 2 in controlled atmosphere (CA: 0°C, 90-95% RH, 1.5 kPaO2 + 0.5 kPa CO 2) (T), or harvested at the optimal maturation stage and cold stored for 9 months under CA (C). Then, they were transferred to shelf-life conditions (22±2°C, 70% RH) and followed for 7 d. Chla fluorescence, scald index (SI), ripening attributes, α-farnesene, conjugated trienols, and photosynthetic pigments were determined for each pear in both groups. Conditions chosen before shelf-life did not prevent the subsequent ripening of any fruit, but changed dramatically the superficial scald development pattern: in C fruit, the disorder developed progressively during shelf-life, whereas in T fruit, it peaked during storage. C fruit exhibited a significant negative correlation (R=-0.65; p<0.05) between Fv/Fm and scald development, but not with ripening (R=-0.15; p<0.05). As expected, the opposite was observed in T fruit, in which only a low, positive, yet significant correlation was found between Fv/Fm and ripening (R=0.44; p<0.05). The multiple regression approach using Fv/Fm and other Chla fluorescence parameters produced an equation from which we calculated the 'predicted' scald index in C fruit. This correlated clearly (R=0.73; p<0.05) with the real values visually assessed. If color values a*, b* and °Hue were included in this multiple regression, the correlation was significantly enhanced (0.91; p<0.05). Although preliminary, this study has shown that basic Chla fluorescence parameters are valuable estimators of superficial scald in 'Rocha' pear and might be used in the early detection of the disorder.