Relationship between specific leaf area, leaf thickness, leaf water content and SPAD-502 readings in six Amazonian tree species

ArticleinPhotosynthetica 47(2):184-190 · June 2009with74 Reads
DOI: 10.1007/s11099-009-0031-6
Abstract
The aim of this work was to assess the effect of leaf thickness, leaf succulence (LS), specific leaf area (SLA), specific leaf mass (Ws) and leaf water content (LWC) on chlorophyll (Chl) meter values in six Amazonian tree species (Carapa guianensis, Ceiba pentandra, Cynometra spruceana, Pithecolobium inaequale, Scleronema micranthum and Swietenia macrophylla). We also tested the accuracy of a general calibration equation to convert Minolta Chl meter (SPAD-502) readings into absolute Chl content. On average, SPAD values (x) increased with fresh leaf thickness (FLT [μm] = 153.9 + 0.98 x, r 2 = 0.06**), dry leaf thickness (DLT [μm] = 49.50 + 1.28 x, r 2 = 0.16**), specific leaf mass (Ws [g (DM) m−2] = 6.73 + 1.31 x, r 2 = 0.43**), and leaf succulence (LS [g(FM)] m−2 = 94.2 + 1.58 x, r 2 = 0.19**). However, a negative relationship was found between SPAD values and either specific leaf area [SLA (m2 kg−1) = 35.1 − 0.37 x, r 2 = 0.38**] or the leaf water content (LWC [%]= 80.0 − 0.42 x, r 2 = 0.58**). Leaf Chl contents predicted by the general calibration equation significantly differed (p<0.01) from those estimated by species-specific calibration equations. We conclude that to improve the accuracy of the SPAD-502 leaf thickness and LWC should be taken into account when calibration equations are to be obtained to convert SPAD values into absolute Chl content.
    • "This evidence is enhanced by the weak relationship of the digital and spectral indices to SLA. This finding is particularly interesting in the case of LCC (SPAD readings), which has been previously positively correlated with leaf thickness and negatively correlated with SLA in other species (Marenco et al., 2009). "
    [Show abstract] [Hide abstract] ABSTRACT: Maize crop production is constrained worldwide by nitrogen (N) availability and particularly in poor tropical and subtropical soils. The development of affordable high-throughput crop monitoring and phenotyping techniques is key to improving maize cultivation under low-N fertilization. In this study several vegetation indices (VIs) derived from Red-Green-Blue (RGB) digital images at the leaf and canopy levels are proposed as low-cost tools for plant breeding and fertilization management. They were compared with the performance of the normalized difference vegetation index (NDVI) measured at ground level and from an aerial platform, as well as with leaf chlorophyll content (LCC) and other leaf composition and structural parameters. A set of ten hybrids grown under five different nitrogen regimes were tested at the CIMMYT station of Harare (Zimbabwe). Grain yield and leaf N concentration across N fertilization levels were strongly predicted by most of these RGB indices (with R2 ~ 0.7), out performing the prediction power of the NDVI and LCC. RGB indices also outperformed the NDVI when assessing genotypic differences in grain yield and leaf N concentration within a given level of N fertilization. The best predictor of leaf N concentration across the five N regimes was LCC but its performance within treatments was inefficient. The leaf traits evaluated also seemed inefficient as phenotyping parameters. It is concluded that the adoption of RGB-based phenotyping techniques may significantly contribute to the progress of plant breeding and the appropriate management of fertilization.
    Full-text · Article · May 2016
    • "The reduction in light intensity induces an increase in chlorophyll content of leaves (Nobel 2009), which may explain the higher chlorophyll content reported in the study of Coste et al. (2010). Although the maximum values of Chl t found in the present study were lower than the values reported by Coste et al. (2010), they are in agreement with values reported for other tropical trees, for instance, Scleronema micranthum (600 mg m -2 ), Swietenia macrophylla, and Ceiba pentandra (900 mg m -2 Marenco et al. 2009). Additionally, the β values calculated individually for each of the 13 species ranged from 88.2 (Cecropia obtusa) to 299.2 (Eperua falcata), with a large dispersion of data in the SPADi range between 40 and 60, and chlorophyll content between 500 and 1000 mg m -2 (Coste et al. 2010). "
    Full-text · Article · May 2016
    • "The reduction in light intensity induces an increase in chlorophyll content of leaves (Nobel 2009), which may explain the higher chlorophyll content reported in the study of Coste et al. (2010). Although the maximum values of Chl t found in the present study were lower than the values reported by Coste et al. (2010), they are in agreement with values reported for other tropical trees, for instance, Scleronema micranthum (600 mg m -2 ), Swietenia macrophylla, and Ceiba pentandra (900 mg m -2 Marenco et al. 2009). Additionally, the β values calculated individually for each of the 13 species ranged from 88.2 (Cecropia obtusa) to 299.2 (Eperua falcata), with a large dispersion of data in the SPADi range between 40 and 60, and chlorophyll content between 500 and 1000 mg m -2 (Coste et al. 2010). "
    [Show abstract] [Hide abstract] ABSTRACT: Individual leaf area (LA) is a key variable in studies of tree ecophysiology because it directly influences light interception, photosynthesis and evapotranspiration of adult trees and seedlings. We analyzed the leaf dimensions (length - L and width - W) of seedlings and adults of seven Neotropical rainforest tree species (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera and Tabebuia stenocalyx) with the objective to test the feasibility of single regression models to estimate LA of both adults and seedlings. In southern Bahia, Brazil, a first set of data was collected between March and October 2012. From the seven species analyzed, only two (P. cattleyanum and T. stenocalyx) had very similar relationships between LW and LA in both ontogenetic stages. For these two species, a second set of data was collected in August 2014, in order to validate the single models encompassing adult and seedlings. Our results show the possibility of development of models for predicting individual leaf area encompassing different ontogenetic stages for tropical tree species. The development of these models was more dependent on the species than the differences in leaf size between seedlings and adults.
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