Modeling of the Leaf Area of <i>Maytenus obtusifolia</i> Mart. from Scanned Images

Abstract

The leaf has a vital role in the functions of the plant, being responsible for photosynthesis and gas exchange. Thus, the objective of this study was to fit a mathematical equation model to estimate the leaf area of Maytenus obtusifolia Mart. through the linear dimensions of the leaves. For that, six hundred and fifteen healthy leaves were collected from plants belonging to the Federal University of Espírito Santo, São Mateus Campus, in the municipality of São Mateus, located in the north of the State of Espírito Santo, Brazil. All leaves were digitized and the images processed using the ImageJ® software, obtaining the measurements of the maximum length of the main midrib (L), the maximum width of the leaf blade (W) and the real leaf area (RLA) of each sheet. Subsequently, the product of length and width multiplication (LW) was also obtained. 500 sheets were randomly separated for the generation of models of mathematical equations and their respective coefficient of determination (R 2), where RLA was used as dependent variable as function of L, W or LW as independent variable. Based on the models generated, a 115 leaf sample was used for validation, where the L, W and LW values of this sample were replaced in the adjusted equations, thus obtaining the estimated leaf area (ELA). A comparison of the means of RLA and ELA was performed by Student's t test at 5% probability. We also calculated the mean absolute error (MAE), the root mean square error (RMSE) and the Willmott index (d). The best equation was defined by the following criteria: non-significant values of RLA and ELA averages, R 2 and index d closest to unit, and MAE and RMSE values with greater proximity to zero. The quadratic model equation

MÉTODO NÃO DESTRUTIVO PARA DETERMINAÇÃO DA ÁREA FOLIAR DE Turnera subulata

“…O uso de equações matemáticas para estimar a área foliar já foi relatada na literatura para diversas espécies (POMPELLI et al, 2012;SCHMILDT et al, 2015;MONTOLATTO et al, 2020;OLIVEIRA et al, 2017;OLIVEIRA et al, 2019;OLIVEIRA et al, 2020;SANTOS et al, 2020;TEOBALDELLI et al, 2020), entretanto, não se encontrou estudos que envolvam esta técnica para estimar a área foliar de T. subulata.…”

“…O estudo foi realizado com folhas de Turnera subulata, coletadas no município de São Mateus, Norte do Estado do Espírito Santo, Brasil, localizado a 18º 40' 36'' de latitude Sul e 39º 51' 35'' de longitude Leste. Foram cotadas 450 folhas de diferentes plantas em todos os estados de desenvolvimento que se mostravam ausentes de danos ou ataques de doenças ou pragas (OLIVEIRA et al, 2017).…”

“…De fato, corroborando com os resultados encontrados neste estudo, a combinação de medidas lineares da superfície foliar, se mostrou mais adequada para Jatropha curcas (POMPELLI et al, 2012), Coffea canephora (SCHMILDT et al, 2015), Litchi chinensis Sonn. (OLIVEIRA et al, 2017), Maytenus obtusifolia Mart. (OLIVEIRA et al, 2019), Allagoptera arenaria (OLIVEIRA et al, 2020) e Tabebuia impetiginosa (Mart.)…”

“…(OLIVEIRA et al, 2017), Maytenus obtusifolia Mart. (OLIVEIRA et al, 2019), Allagoptera arenaria (OLIVEIRA et al, 2020) e Tabebuia impetiginosa (Mart.) (SANTOS et al, 2020), sendo essas equações capazes de fornecer com maior exatidão a área foliar destas espécies.…”