Description
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We analyze the effect of different variables on the concentrations of 4-Hydroxybenzoic acid (4-HBA), chlorogenic acid (CGA) and quercetin (QUE) in female and hermaphrodite individuals of Opuntia robusta from San Nicolas Tecoaso, Municipality of Singuilucan, Hidalgo State, Central Mexico, using general linear mixed models (GLMM). To analyze the effect of months and age on 4-HBA concentrations, we used the Gamma error distribution (GED) and the inverse link function. For the effect of months on CGA concentrations, we used GED and log link functions. For the effect of cladode age on CGA concentrations, GED and inverse link functions. For the effect of months on QUE concentration, GED and log link functions. For the effect of cladode age on QUE concentration, GED and inverse link function. For the models that related substances with cladode length, width and thickness, we used different models: for 4-HBA concentrations we used a GED with square root link function. For CGA concentrations, GED and identity link function, and for QUE concentrations, GED and inverse link function. To test the effect of cladodes order from soil on the concentrations of the three substances, we used GED and square root link function. To test the effect of the number of cladodes above a given cladode on the concentrations of the three substances, we used GED and inverse link function. We checked the goodness of fit of the linear models (GLMM) by plotting the standardized residuals against fitted values and by normal QQ‐plots, and revised the assumptions of the homoscedasticity, proper distribution used, and independence. We chose the best GLM model used in this study according to the lowest AIC (Akaike, 1974; Akaike, 1987). (2020-08-09) |