Ecophysiology Responses of Andiroba Seedlings (Carapa Guianensis Aubl.) Under Different Levels of Shading

Abstract

Defining the best conditions for the initial development of native species is one of the significant challenges to forest production. Therefore, this study aimed to evaluate andiroba's physiological behavior and growth (Carapa guianensis Aubl.) seedlings at different shading levels. In a nursery seedling, C. guianensis seedlings grew on 0, 30, 50, and 70% shading, obtained with polyethylene screens. We measured at six plants per treatment. For the physiological data we measurement four times the total chlorophyll content, chlorophyll a/b ratio, maximum photochemical efficiency of photosystem II (Fv/Fm), maximum potential photosynthesis (A), stomatal conductance (gs), transpiration (E), intrinsic water use efficiency (WUEi), and carbon use efficiency (CUE), besides the growth parameters. While for growth rates parameters we developed six evaluation for as leaf area ratio (LAF), relative growth rates (RGR), and net assimilation rate (NAR). Chlorophyll content and Fv/Fm were inversely proportional to the light intensity. The other physiological and growth parameters showed better behavior in shaded environments, emphasizing the 50% treatment, with no significant difference between the 30% shading treatment. Therefore, the C. guianensis seedlings present growth plasticity under different shading levels, and we recommended producing seedlings at 50 or 30% shading.